Method of operating a shift system for a vehicle transmission

Abstract

A method of operating a shift system for a vehicle transmission, comprising: engaging a clutch to operatively couple one of a first gear ratio and a second gear ratio to an input member; and moving a disconnect member from a first disconnect position, in which a disconnectable component is disengaged from the disconnect member, to a second disconnect position, in which the disconnectable component is engaged with the disconnect member, to operatively couple the other of the first gear ratio and the second gear ratio to the input member through a shift assembly. Engaging the clutch and moving the disconnect member is performed such that the clutch is operatively coupled to one of the first gear ratio and the second gear ratio while the shift assembly is operatively coupled to the other of the first gear ratio and the second gear ratio, thereby preventing torque from being transmitted through either of the first gear ratio and the second gear ratio of the vehicle transmission to park the vehicle.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and all the benefits of U.S. Provisional Patent Application No. 62 / 946,156, filed on December 10, 2019, and U.S. Provisional Patent Application No. 63 / 091,794, filed on October 14, 2020, which are expressly incorporated herein by reference in their entireties. Technical Field

[0003] The present invention generally relates to a method of operating a shift system for a vehicle transmission. Background Art

[0004] Conventional vehicles known in the art typically include an engine having a rotational output as a rotational input into a vehicle transmission. The engine is typically an internal combustion engine or an electric engine, and generates a rotational output that is selectively transmitted to a vehicle transmission, which in turn transmits a rotational torque to one or more wheels of the vehicle. The vehicle transmission varies the rotational speed and torque generated by the engine through a series of predetermined gear sets, whereby the change between the gear sets enables the vehicle to travel at different vehicle speeds for a given engine speed. Typically, the engine is an electric engine coupled to a vehicle transmission, which is in an axle connected to the wheels of the vehicle.

[0005] A rotational input into a vehicle transmission typically requires a shift system to selectively transmit torque to components of the vehicle transmission. A typical shift system includes an input member rotatable about an axis (e.g., a rotational output from an engine), a disconnect coupled to the input member, and an output member selectively rotatable about an axis with the input member (e.g., a rotational input to the vehicle transmission). Typically, a shift assembly is also required to selectively rotatably couple the input member and the output member.

[0006] Shift systems known in the prior art often suffer from high drag losses, which reduce the efficiency of torque transfer between the engine and the vehicle transmission. In addition, typical shift systems produce rough engagement between components of the engine and the vehicle transmission by connecting to disconnect members, resulting in vehicle vibration and an uncomfortable driving experience.

[0007] Therefore, it is desirable to provide an improved shifting system for a vehicle transmission. Summary of the invention

[0008] A shifting system for a vehicle transmission includes an input member extending along an axis between a first end and a second end, the second end being spaced apart from the first end. The vehicle transmission has a gear set including a first gear ratio and a second gear ratio different from the first gear ratio. The input member is rotatable about the axis. The shifting system further includes a clutch coupled to the input member. The clutch is configured to selectively allow torque to be transmitted from the input member through one of the first gear ratio and the second gear ratio of the gear set.

[0009] The shift system also includes a disconnect member coupled to the input member. The disconnect member is movable between a first disconnect position and a second disconnect position. The output member is spaced apart from the input member, and the output member is selectively rotatable with the input member about an axis to selectively transmit torque through the other of the first gear ratio and the second gear ratio of the gear set.

[0010] The shift system further includes a shift assembly for selectively rotatably coupling the input member and the output member. The shift assembly includes an input hub coupled to the input member. The input hub has a disconnectable component that can engage with a disconnect member, and when the disconnect member is in a first disconnect position, the disconnectable component of the input hub is separated from the disconnect member, and when the disconnect member is in a second disconnect position, the disconnectable component of the input hub is engaged with the disconnect member.

[0011] The input hub has a clutch engaging member. The shift assembly also includes a plurality of clutch plates, which are coupled to the clutch engaging member of the input hub. The plurality of clutch plates are movable between an engaged position and a disengaged position. In the engaged position, the clutch plates are engaged with each other. In the disengaged position, the clutch plates are disengaged from each other. The shift assembly further includes a clutch plate carrier, which is coupled to the plurality of clutch plates and is coupled to the output member to transfer torque from the clutch engaging member of the input hub to the output member through the plurality of clutch plates and the clutch plate carrier.

[0012] Thus, the shift system results in low belt losses, which increases the efficiency of torque transmission between the engine and the vehicle transmission. In addition, the shift system produces a smooth engagement between the engine and the vehicle transmission through the shift assembly (i.e., through the connection with the disconnect member and the engagement of the plurality of clutch plates), resulting in less vibration and a more comfortable driving experience. In addition, when torque does not need to be transmitted through the shift assembly, the clutch allows the shift system to achieve low rotational losses by rotatably decoupling the shift assembly. The low rotational losses allowed by the combination of the clutch and the shift assembly allow a first gear ratio and a second gear ratio of the vehicle transmission to achieve a net energy savings compared to a single speed transmission.

[0013] In addition, a method of operating a shift system for a vehicle transmission includes the steps of: engaging a clutch to operatively couple one of a first gear ratio and a second gear ratio to an input member. The method also includes the steps of: moving a disconnect member from a first disconnect position, in which a disconnectable component of an input hub is disengaged from the disconnect member, to a second disconnect position, in which the disconnectable component of the input hub is engaged with the disconnect member, to operatively couple the other of the first gear ratio and the second gear ratio to the input member through the shift assembly.

[0014] The steps of engaging the clutch and moving the disconnect member from the first disconnected position to the second disconnected position are performed so that the clutch is operatively coupled to one of the first gear ratio and the second gear ratio while the shift assembly is operatively coupled to the other of the first gear ratio and the second gear ratio, thereby preventing torque from being transmitted through either of the first gear ratio and the second gear ratio of the vehicle transmission to park the vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Other advantages of the present invention will be readily appreciated as they become better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings, wherein:

[0016] Figure 1A is a schematic illustration of a vehicle transmission for a vehicle, the vehicle transmission including a shifting system having: an electric motor; an input member; a clutch rotatably coupled to and disposed about the input member for selectively transmitting torque through a first gear ratio; and a shift assembly coupled to the input member for selectively transmitting torque through a second gear ratio;

[0017] Figure 1B is a schematic illustration of a vehicle transmission including a countershaft with a selectable one-way clutch rotatably coupled to an input member and a shift assembly coupled to the countershaft;

[0018] Figure 2A is a schematic illustration of a vehicle transmission in which a clutch is rotatably coupled to and disposed about a layshaft, and a shift assembly is coupled to an input member;

[0019] Figure 2B is a schematic illustration of a vehicle transmission in which a selectable one-way clutch is rotatably coupled to and disposed about a layshaft, and a shift assembly is coupled to the layshaft;

[0020] Figure 3is a schematic illustration of a shifting schedule for a shifting system of a vehicle transmission, wherein X / X represents a first clutch position, X / O represents a second clutch position, O / O represents a third clutch position, O / X represents a fourth clutch position, DP1 represents a first disconnected position, DP2 represents a second disconnected position, ENG represents an engaged position of a clutch plate of a shift assembly, and D-ENG represents a disengaged position of a clutch plate;

[0021] Figure 4A is a perspective view of a selectable one-way clutch, wherein the selectable one-way clutch is of a fixed variety, and wherein the selectable one-way clutch has: an inner race, an outer race, a plurality of pawls circumferentially spaced from one another, and an actuator ring connected to the pawls;

[0022] Figure 4B is a perspective view of a selectable one-way clutch, wherein the selectable one-way clutch is of a rotary variety;

[0023] Figure 4C yes Figure 4B A cross-sectional view of a selectable one-way clutch;

[0024] Figure 5A is a cross-sectional view of a shift assembly having an apply plate and a plurality of clutch plates with a disconnect member in a first disconnect position wherein the disconnect member is disengaged from an input hub of the shift assembly and the apply plate in a first plate position wherein the plurality of clutch plates are in an engaged position;

[0025] Figure 5B is a cross-sectional view of the shift assembly with the disconnect member in a first disconnect position wherein the disconnect member is separated from the input hub, and the apply plate in a second plate position wherein the plurality of clutch plates are in a disengaged position;

[0026] Figure 5C is a cross-sectional view of the shift assembly with the disconnect member in a second disconnect position, wherein the disconnect member is engaged with the input hub, and the apply plate is in a second plate position, wherein the plurality of clutch plates are in a disengaged position;

[0027] Figure 5D is a cross-sectional view of the shift assembly with the disconnect member in a second disconnect position wherein the disconnect member is engaged with the input hub, and the apply plate in a first plate position wherein the plurality of clutch plates are in an engaged position;

[0028] Fig. 6A is a cross-sectional view of a shift assembly, wherein the disconnect member is a synchronizer, and wherein the disconnect member is in a first disconnect position, wherein the disconnect member is disengaged from the input hub, and the apply plate is in a first plate position, wherein the plurality of clutch plates are in an engaged position;

[0029] Figure 6B is a cross-sectional view of a shift assembly, wherein the disconnect member is a synchronizer, and wherein the disconnect member is in a first disconnect position, wherein the disconnect member is disengaged from the input hub, and the apply plate is in a second plate position, wherein the plurality of clutch plates are in a disengaged position;

[0030] Figure 6C is a cross-sectional view of a shift assembly, wherein the disconnect member is a synchronizer, and wherein the disconnect member is in a second disconnect position, wherein the disconnect member is engaged with the input hub, and the apply plate is in a second plate position, wherein the plurality of clutch plates are in a disengaged position;

[0031] Fig.6D is a cross-sectional view of a shift assembly, wherein the disconnect member is a synchronizer, and wherein the disconnect member is in a second disconnect position, wherein the disconnect member is engaged with the input hub, and the apply plate is in a first plate position, wherein the plurality of clutch plates are in an engaged position;

[0032] Fig. 7A is a cross-sectional view of the shift assembly with the disconnect member in a first disconnect position, wherein the disconnect member is separated from the input hub, and the apply plate is in a first plate position, wherein the plurality of clutch plates are in an engaged position;

[0033] Figure 7B is a cross-sectional view of the shift assembly with the disconnect member in a first disconnect position wherein the disconnect member is separated from the input hub, and the apply plate in a second plate position wherein the plurality of clutch plates are in a disengaged position;

[0034] Figure 7C is a cross-sectional view of the shift assembly with the disconnect member in a second disconnect position, wherein the disconnect member is engaged with the input hub, and the apply plate is in a second plate position, wherein the plurality of clutch plates are in a disengaged position;

[0035] Fig.7D is a cross-sectional view of the shift assembly with the disconnect member in a second disconnect position wherein the disconnect member is engaged with the input hub, and the apply plate in a first disconnect position wherein the plurality of clutch plates are in an engaged position;

[0036] Figure 8 is a flow chart of a method of operating a shifting system, wherein the method is directed to shifting a transfer of torque between a first gear ratio and a second gear ratio; and

[0037] Fig. 9 is a flow chart of a method of operating a shift system, wherein the method is directed to parking a vehicle. DETAILED DESCRIPTION

[0038] Referring to the accompanying drawings, wherein like numerals refer to like parts throughout the several views, Figures 1A to 2B A vehicle transmission 10 is provided in a schematic illustration in FIG. The vehicle transmission 10 has a gear set 12 including a first gear ratio 14 and a second gear ratio 16 different from the first gear ratio 14. Figures 1A to 2B A shifting system 18 for a vehicle transmission 10 is shown in FIG.

[0039] The shift system 18 includes an input member 20 extending along an axis A between a first end 22 and a second end 24, the second end 24 being spaced apart from the first end 22. The input member 20 is rotatable about the axis A. As a non-limiting example, the input member 20 may be a shaft or a gear. The shift system 18 also includes a clutch 25 coupled to the input member 20. The clutch 25 is configured to selectively allow torque to be transmitted from the input member 20 through one of the first gear ratio 14 and the second gear ratio 16 of the gear set 12. The clutch 25 may be of various clutch types and configurations, which are described in further detail below. It is noteworthy that, although not required, the clutch 25 may be a selectable one-way clutch 26. The selectable one-way clutch 26 is rotatably coupled to the input member 20, and the selectable one-way clutch 26 may be in a first clutch position (in a Figure 3 Indicated as X / X), the second clutch position (in Figure 3 Indicated as X / O) and the third clutch position (in Figure 3 Move between (indicated as O / O).

[0040] In the first clutch position X / X, if Figure 3 As shown in , the selectable one-way clutch 26 is configured to allow torque to be transmitted from the input member 20 through one of the first gear ratio 14 and the second gear ratio 16 of the gear set 12 in the first rotational direction D1 or the second rotational direction D2 opposite to the first rotational direction. In the first clutch position X / X, the selectable one-way clutch 26 is in a locked / locked configuration. In this locked / locked configuration, torque can be transmitted from the input member 20 through one of the first gear ratio 14 and the second gear ratio 16 in the first rotational direction D1. It will also be understood that torque can be transmitted to the input member 20 through one of the first gear ratio 14 and the second gear ratio 16 in the second rotational direction D2. In other words, in the first clutch position X / X, torque can be transmitted in either the first rotational direction D1 or the second rotational direction D2. It will be understood that the first rotational direction D1 may be a clockwise direction and the second rotational direction D2 may be a counterclockwise direction. Alternatively, it will be understood that the first rotational direction D1 may be a counterclockwise direction and the second rotational direction D2 may be a clockwise direction.

[0041] In the second clutch position X / O, if Figure 3As shown in , the selectable one-way clutch 26 is configured to allow torque to be transmitted from the input member 20 through one of the first gear ratio 14 and the second gear ratio 16 of the gear set 12 in the first rotational direction D1, and prevent torque from being transmitted from the input member 20 through one of the first gear ratio 14 and the second gear ratio 16 of the gear set 12 in the second rotational direction D2. In the second clutch position X / O, the selectable one-way clutch 26 is in a locked / free configuration. In this locked / free configuration, torque can be transmitted from the input member 20 through one of the first gear ratio 14 and the second gear ratio 16 in the first rotational direction D1. However, torque is prevented from being transmitted to the input member 20 through one of the first gear ratio 14 and the second gear ratio 16 in the second rotational direction D2. This locked / free configuration is typically referred to as over-running the selectable one-way clutch 26, and assists in shifting the transmission of torque: from or through the first gear ratio 14 to the second gear ratio 16, or through the second gear ratio 16 to the first gear ratio 14. Therefore, the second clutch position X / O can be referred to as shift ready.

[0042] In the third clutch position O / O, if Figure 3 As shown in , the selectable one-way clutch 26 is configured to prevent torque from being transmitted from the input member 20 through one of the first gear ratio 14 and the second gear ratio 16 of the gear set 12 in either the first rotational direction D1 or the second rotational direction D2. In the third clutch position O / O, the selectable one-way clutch 26 is in a free / free configuration. In the free / free configuration, torque is prevented from being transmitted from the input member 20 through one of the first gear ratio 14 and the second gear ratio 16 in the first rotational direction D1. In the free / free configuration, torque is also prevented from being transmitted to the input member 20 through one of the first gear ratio 14 and the second gear ratio 16 in the second rotational direction D2. The free / free configuration limits band losses on the shift system 18 by rotatably decoupling one of the first gear ratio 14 and the second gear ratio 16 from the input member 20.

[0043] The shift system 18 also includes a disconnect member 28 coupled to the input member 20. The disconnect member 28 can be in a first disconnect position DP1 (eg, Figure 3 , 5A , 5B, 6A, 6B, 7A and 7B) and the second disconnection position DP2 (as shown in Figure 3 , 5C, 5D, 6C, 6D, 7C and 7D). The shift system 18 also includes an output member 30 that is spaced apart from the input member 20 and is selectively rotatable with the input member 20 about the axis A to selectively transmit torque through the other of the first gear ratio 14 and the second gear ratio 16 of the gear set 12.

[0044] The shift system 18 further includes a shift assembly 32 for selectively rotatably coupling the input member 20 and the output member 30. The shift assembly 32 includes an input hub 34 coupled to the input member 20. The input hub 34 has a disconnectable component 36 that can engage with the disconnect member 28, and when the disconnect member 28 is in the first disconnect position DP1, the disconnectable component 36 of the input hub 34 is separated from the disconnect member 28, and when the disconnect member 28 is in the second disconnect position DP2, the disconnectable component 36 of the input hub 34 is engaged with the disconnect member 28.

[0045] The disconnect member 28 rotatably disconnects the input member 20 and the disconnectable component 36, thereby rotatably disconnecting the input member 20 and the input hub 34. In one embodiment, the disconnect member 28 is a disconnect clutch. Alternatively, in another embodiment, the disconnect member 28 is a synchronizer. In the embodiment in which the disconnect member 28 is a synchronizer, the synchronizer may have: a synchronizer ring, a synchronizer cone, a synchronizer hub, and a synchronizer sleeve. In yet another embodiment, the disconnect member 28 is a dog clutch.

[0046] The input hub 34 has a clutch engaging member 38. The shift assembly 32 includes a plurality of clutch plates 40 coupled to the clutch engaging member 38 of the input hub 34. The plurality of clutch plates 40 are movable between an engaged position ENG and a disengaged position D-ENG. In the engaged position ENG, as shown in FIG. Figure 3 , 5A , 5D, 6A, 6D, 7A and 7D, the clutch plates 40 are engaged with each other. In the disengaged position D-ENG, as shown in FIG. Figure 3 , 5B , 5C, 6B, 6C, 7B and 7C, the clutch plates 40 are separated from each other. The shift assembly 32 also includes a clutch plate carrier 42, which is coupled to the plurality of clutch plates 40 and is coupled to the output member 30 to transfer torque from the clutch engaging part 42 of the input hub 34 to the output member 30 through the plurality of clutch plates 40 and the clutch plate carrier 42.

[0047] The shift system 18 results in low shift losses, which increases the efficiency of torque transfer between the engine and the vehicle transmission 10. In addition, the shift system 18 produces a smooth engagement between the engine and the vehicle transmission 10 through the shift assembly 32 (i.e., through the connection with the disconnect 28 and the engagement of the plurality of clutch plates 40), resulting in less vibration and a more comfortable driving experience. In addition, the clutch 26 allows the shift system 18 to achieve low spin losses by rotationally decoupling the shift assembly 32 when torque does not need to be transferred through the shift assembly 32. The low spin losses allowed by the combination of the clutch 26 and the shift assembly 32 allow the first gear ratio 14 and the second gear ratio 16 of the vehicle transmission 10 to achieve a net energy savings compared to a single speed transmission.

[0048] As discussed above, it will be appreciated that the clutch 25 can be a variety of clutch types and configurations. In a non-limiting example, the clutch 25 can be a selectable one-way clutch 26. However, in other non-limiting examples, the clutch 25 can be another shift assembly as described herein, can be a dry friction clutch, can be a wet friction clutch, can be a single plate clutch, can be a multi-plate clutch, can be a cone clutch, can be a dog clutch, or can be a centrifugal clutch.

[0049] It will be understood that the engine may be an internal combustion engine or may be an electric engine. It will also be understood that the engine may be coupled to the rear axle of the vehicle. In one embodiment, the engine is an electric engine and is rotatably coupled to the rear axle of the vehicle and is configured to rotate the rear axle of the vehicle to propel the vehicle.

[0050] like FIG. 4A to FIG. 4C As shown in FIG. 1 , the selectable one-way clutch 26 may have an inner race 44 and an outer race 46 disposed around the inner race 44. In other words, the inner race 44 and the outer race 46 may be concentric with each other. In one embodiment, as shown in FIG. Figure 1A and Figure 1B As shown in FIG. 1 , the inner race 44 and the outer race 46 of the selectable one-way clutch 26 can be disposed about the input member 20 and axially aligned with the input member 20. The inner race 44 of the selectable one-way clutch 26 can be rotatably coupled with the input member 20. In a non-limiting example, the inner race 44 can be splined to the input member 20 such that rotation of the input member 20 causes rotation of the inner race 44 of the selectable one-way clutch 26. Additionally or alternatively, the inner race 44 of the selectable one-way clutch 26 can be bolted to the input member 20 or otherwise mechanically fastened to the input member 20.

[0051] The selectable one-way clutch 26 may also have at least one pawl 48 disposed between the inner race 44 and the outer race 46. The pawl 48 selectively rotatably couples the inner race 44 and the outer race 46. In a non-limiting example, the pawl 48 may rotatably engage both the inner race 44 and the outer race 46 to prevent relative rotation between the inner race 44 and the outer race 46. It will be understood that the pawl 48 may allow a rotational coupling between the inner race 44 and the outer race 46 in a first rotational direction D1 while preventing a rotational coupling between the inner race 44 and the outer race 46 in a second rotational direction D2. Alternatively, it will be understood that the pawl 48 may allow a rotational coupling between the inner race 44 and the outer race 46 in a second rotational direction D2 while preventing a rotational coupling between the inner race 44 and the outer race 46 in the first rotational direction D1. The pawl 48 may also prevent or allow a rotational coupling between the inner race 44 and the outer race 46 in both the first rotational direction D1 and the second rotational direction D2.

[0052] The at least one pawl 48 may be further defined as a plurality of pawls 50 circumferentially spaced from one another. The selectable one-way clutch 26 may further include an actuator ring 52 coupled to the plurality of pawls 50 for selectively rotatably locking the inner race 44 and the outer race 46 together. The actuator ring 52 may be in physical contact with the pawls 50 such that movement of the actuator ring 52, such as rotation of the actuator ring 52, results in movement of the pawls 50, such as rotation of the pawls 50. The actuator ring 52 may be electrically actuated by a small electric motor or solenoid. The small electric motor or solenoid may be coupled to the outer race 46 of the selectable one-way clutch 26. It will also be understood that the actuator ring 52 may be hydraulically, pneumatically, or otherwise actuated.

[0053] The shift assembly 32 may further include a biasing member 54 coupled to the plurality of clutch plates 40 to bias the plurality of clutch plates 40 toward the engagement position ENG. In other words, in the engagement position ENG, the plurality of clutch plates 40 may be normally closed and at rest. Because the plurality of clutch plates 40 of the stationary shift assembly 32 are in the engagement position ENG due to the biasing member 54 biasing the plurality of clutch plates 40 toward the engagement position ENG, the shift assembly 32 is energy efficient, and therefore, the shift system 18 is also energy efficient. In other words, because power from an electronic actuator or a hydraulic actuator is not required to maintain the plurality of clutch plates 40 in the engagement position ENG, the shift assembly 32 is energy efficient, and therefore, the shift system 18 is energy efficient.

[0054] The shift assembly 32 may further include an apply plate 56 coupled to the biasing member 54. The apply plate 56 may be movable between a first plate position, in which the plurality of clutch plates 40 are in the engaged position ENG, and a second plate position, in which the apply plate 56 is engaged with the biasing member 54 and the plurality of clutch plates 40 are in the disengaged position D-ENG.

[0055] In one embodiment, the apply plate 56 and the disconnect member 28 are movable independently of each other. The apply plate 56 can be moved from the first plate position to the second plate position, causing the plurality of clutch plates 40 to move from the engaged position ENG to the disengaged position D-ENG, regardless of whether the disconnect member 28 is in the first position, the disconnect position DP1, or the second disconnect position DP2, and without affecting the position of the disconnect member 28. Similarly, the disconnect member 28 can be moved from the first disconnect position DP1 to the second disconnect position DP2, causing the input hub 34 to be engaged, regardless of whether the apply plate 56 is in the first plate position or the second plate position, and without affecting the position of the apply plate 56.

[0056] In embodiments where the apply plate 56 and the disconnect member 28 are movable independently of each other, the shift system 18 may further include: a first actuator coupled to the disconnect member 28 to move the disconnect member 28 from the first disconnect position DP1 to the second disconnect position DP2 independently of the apply plate 56; and a second actuator coupled to the apply plate 56 to move the apply plate 56 from the first plate position to the second plate position independently of the disconnect member 28. It will be understood that the first actuator and the second actuator may be movable by, but not limited to, mechanical actuation, electrical actuation, hydraulic actuation, or pneumatic actuation.

[0057] In some embodiments, when the disconnect piece 28 is in the second disconnect position DP2 and the apply plate 56 is in the first plate position, the input member 20 is rotatably coupled to the output member 30. In other words, the input member 20 can be rotatably coupled to the output member 30 when the apply plate 56 is in the first plate position, in which the biasing member 54 can bias the plurality of clutch plates 40 toward the engaged position ENG, and when the disconnect piece 28 is in the second disconnect position DP2, in which the disconnect piece 28 is engaged with the input hub 34. In these positions, torque can be transmitted from the input member 20 to the output member 30 through the input hub 34, the plurality of clutch plates 40, and the clutch plate carrier 42.

[0058] In some embodiments, when the disconnect member 28 is in the first disconnect position DP1 and / or when the apply tab 56 is in the second tab position, the input member 20 is rotationally decoupled from the output member 30. In other words, either when the disconnect member 28 is in the first disconnect position DP1, or when the apply tab 56 is in the second tab position, or when the disconnect member 28 is in the first disconnect position DP1 and the apply tab 56 is in the second tab position, the input member 20 is rotationally decoupled from the output member 30. In these positions, torque cannot be transmitted from the input member 20 to the output member 30.

[0059] Only when the disconnect member 28 is in the second disconnect position DP2 and the apply plate 56 is in the first plate position, in the embodiment in which the input member 20 is rotatably coupled to the output member 30, the disconnect member 28 and the plurality of clutch plates 40 are arranged in series with each other. In other words, if the disconnect member 28 is in the first disconnect position DP1 in which the disconnect member 28 is separated from the input hub 34, or the apply plate 56 is in the second plate position in which the plurality of clutch plates 40 are separated, the input member 20 is rotatably decoupled from the output member 30. Therefore, when arranged in series, the disconnect member 28 must be engaged with the input hub 34, and the plurality of clutch plates 40 must be engaged with each other to directly transmit torque from the input member 20 to the output member 30.

[0060] The disconnectable component 36 of the input hub 34 and the clutch engaging component 42 of the input hub 34 may be integral with each other. Alternatively, the disconnectable component 36 of the input hub 34 and the clutch engaging component 42 of the input hub 34 may be separate components. In some embodiments, the clutch engaging component 42 of the input hub 34 may be rotatably connected to the disconnectable component 36 of the input hub 34 by using a key, a tab, or a bolt. It will be understood that the input hub 34 may be more than two components and may include a third component or more to transfer torque from the input member 20 to the plurality of clutch plates 40.

[0061] In some embodiments, 5A to 6D As shown in , the shift assembly 32 further includes an intermediate application plate 58, which is coupled to the application plate 56 so that the application plate 56 is disposed between the intermediate application plate 58 and the biasing member 54. The application plate 56 can be contacted by the intermediate application plate 58 in the first plate position to engage the plurality of clutch plates 40. In this embodiment, the intermediate application plate 58 transmits force to the application plate 56, and thus to the biasing member 54, so that the biasing member 54 moves and causes the plurality of clutch plates 40 to be in the disengaged position D-ENG. It will be understood that the intermediate application plate 58 can also be generally referred to as a release plate.

[0062] Although not required, the shift assembly 32 may further include a support ring 60 disposed between the biasing member 54 and the clutch engaging member 42 to support the plurality of clutch plates 40. The support ring 60 may be disposed about the axis A and may be rotatable with either the input member 20 or the output member 30. FIG. 7A to FIG. 7D As shown in FIG. 8 , the support ring 60 may be spaced apart from the plurality of clutch plates 40 along the axis A and may be rotatably coupled to the clutch plate carrier 42 .

[0063] In some embodiments, FIG. 7A to FIG. 7D As shown in , the biasing member 54 is spaced apart from the clutch engaging component 42 of the input hub 34 and the clutch plate carrier 42 along the axis A, so that the clutch engaging component 42 of the input hub 34 is disposed between the biasing member 54 and the clutch plate carrier 42. In this embodiment, the support ring 60 is disposed between the biasing member 54 and the plurality of clutch plates 40, and between the biasing member 54 and the clutch engaging component 42 of the input hub 34.

[0064] In other embodiments, FIG. 7A to FIG. 7D , the clutch engaging component 42 of the input hub 34 is spaced apart from the biasing member 54 and the clutch plate carrier 42 along the axis A, such that the biasing member 54 is disposed between the clutch engaging component 42 of the input hub 34 and the clutch plate carrier 42. In this embodiment, the support ring 60 is disposed between the biasing member 54 and the clutch engaging component 42.

[0065] In some embodiments, the biasing member 54 is a Belleville spring. However, it will be understood that the biasing member 54 can be any type of spring, including but not limited to a wave spring, a coil spring, and a conical spring.

[0066] like 5A to 6D , the output member 30 may be spaced apart from the input member 20 along the axis A. In embodiments where the output member 30 is spaced apart from the input member 20 along the axis A, the input member 20 may be a shaft and the output member 30 may also be a shaft. In this embodiment, the output member 30 may be the sole output of the shift system 18 .

[0067] It will be understood that in 5A to 6D In the embodiment illustrated in FIG. 1 , the apply plate 56 can be translated along the axis from the first plate position to the second plate position to translate the biasing member 54 along the axis. In doing so, the plurality of clutch plates 40 move from the engaged position ENG to the disengaged position D-ENG.

[0068] like FIG. 7A to FIG. 7DAs shown in , the output member 30 may be radially spaced from the input member 20 and disposed around the input member 20. In embodiments where the output member 30 is radially spaced from the input member 20 and disposed around the input member 20, the output member 30 may be one of at least two outputs of the shift system 18. Another output other than the output member 30 itself may be the input member 20. In other words, if the disconnect member 28 is in the first disconnect position DP1 or the apply plate 56 is in the second plate position, the input member 20 may still be capable of transmitting torque. It will be understood that in embodiments where the output member 30 is radially spaced from the input member 20 and disposed around the input member 20, the output member 30 may be a gear.

[0069] It will be understood that in FIG. 7A to FIG. 7D , the biasing member 54 may pivot about a pivot point of the biasing member 54 as the section of the apply plate 56 closest to the input member 20 translates along the axis A. In doing so, the section of the apply plate 56 farthest from the input member 20 moves away from the plurality of clutch plates 40, and the plurality of clutch plates 40 moves from the engaged position ENG to the disengaged position D-ENG. It will be appreciated that a pivot point is shown, and the biasing member 54 may pivot at the pivot point where both the support ring 60 and the additional back plate contact the biasing member 54. The contact areas of the support ring 60 and the additional back plate where the support ring 60 and / or the additional back plate contact the biasing member 54 may be hardened to prevent wear.

[0070] In some embodiments, Figure 3 As shown in , the selectable one-way clutch 26 can be further moved to a fourth position, wherein the selectable one-way clutch 26 is configured to allow torque to be transmitted from the input member 20 through one of the first gear ratio 14 and the second gear ratio 16 of the gear set 12 in the second rotational direction D2, and prevent torque from being transmitted from the input member 20 through one of the first gear ratio 14 and the second gear ratio 16 of the gear set 12 in the first rotational direction D1. In these embodiments, the selectable one-way clutch 26 is typically referred to as a four-mode clutch. It will also be understood that the selectable one-way clutch 26 can also be referred to as a multi-mode clutch module. Examples of multi-mode clutch modules are described in U.S. Patent Nos. 9,151,345 (filed on June 2, 2014 and issued on October 6, 2015) and 9,726,236 (filed on January 27, 2014 and issued on August 8, 2017), the disclosures of which are incorporated by reference in their entirety.

[0071] The selectable one-way clutch 26 can be moved to the fourth clutch position (in Figure 3In an embodiment (denoted as O / X in the figure), the shift system 18 can allow regeneration of the electric motor. More specifically, the shift system 18 can allow regenerative braking. Torque can be transmitted from one of the first gear ratio 14 and the second gear ratio 16 to the electric motor through the selectable one-way clutch 26 and / or the shift assembly in the fourth clutch position O / X. In this case, the electric motor can be a generator that converts the rotational movement of the input member 20 into electrical energy.

[0072] The vehicle transmission may also include a layshaft 62 that is spaced apart from the input member 20 and rotatable about the second axis CA. It will be appreciated that the layshaft 62 may also be referred to as a layshaft 62. The clutch 26 may be configured to transfer torque from the input member 20 to the layshaft 62 through the first gear ratio 14. The shift assembly 32 may be configured to transfer torque from the output member 30 to the layshaft 62 through the second gear ratio 16. It will be appreciated that the output member 30 may be a shaft, a gear, or even the layshaft 62 itself.

[0073] It will be understood that if Figure 1A and 1B As shown in FIG, the inner race 44 and the outer race 46 of the selectable one-way clutch 26 can be disposed around the input member 20 and axially aligned with the input member 20. It will also be understood that in embodiments where the inner race 44 and the outer race 46 of the selectable one-way clutch 26 are disposed around the input member 20 and axially aligned with the input member 20, the shift assembly 32 can be either Figure 1A is coupled to the input member 20 as shown in Figure 1B 6 and 7. As shown in FIG.

[0074] In another embodiment, Figure 2A and 2B As shown in , the inner race 44 and the outer race 46 of the selectable one-way clutch 26 are disposed about and axially aligned with the countershaft 62. In this embodiment, the input member 20 extends directly from the engine to the shift assembly 32. However, it will be understood that in either or both of the embodiments in which the selectable one-way clutch 26 is disposed about and axially aligned with the input member 20 or the embodiments in which the selectable one-way clutch 26 is disposed about and axially aligned with the countershaft 62, the input member 20 can be solid, unitary and one-piece. It will also be understood that in the embodiments in which the inner race 44 and the outer race 46 of the selectable one-way clutch 26 are disposed about and axially aligned with the countershaft 62, the shift assembly 32 can either be as Figure 2A is coupled to the input member 20 as shown in Figure 2B 6 and 7. As shown in FIG.

[0075] A method 100 of operating the shift system 18 is also provided. The method 100 includes the step 102 of moving the selectable one-way clutch 26 from a first clutch position X / X to a second clutch position X / O, in which the selectable one-way clutch 26 is configured to allow torque to be transmitted from the input member 20 through one of the first gear ratio 14 and the second gear ratio 16 in a first rotational direction D1 or a second rotational direction D2 opposite the first rotational direction, and in which the selectable one-way clutch 26 is configured to allow torque to be transmitted from the input member 20 through one of the first gear ratio 14 and the second gear ratio 16 in the first rotational direction D1 and prevent torque from being transmitted from the input member 20 through one of the first gear ratio 14 and the second gear ratio 16 in the second rotational direction D2. Figure 3 Step 102 of moving the selectable one-way clutch 26 from a first clutch position X / X to a second clutch position X / O is indicated in FIG. 1 by a shift schedule, in particular by elements A and B.

[0076] The method 100 further includes step 104 of moving the plurality of clutch plates 40 from an engaged position ENG in which the clutch plates 40 are engaged with each other to a disengaged position D-ENG in which the clutch plates 40 are disengaged from each other. Figure 3 Step 104 of moving the clutch plate 40 from the engaged position ENG to the disengaged position D-ENG is indicated in FIG. 1 by the shifting schedule, in particular by the element C.

[0077] The method 100 further includes a step 106 of moving the disconnect member 28 from a first disconnect position DP1 in which the disconnectable component 36 of the input hub 34 is separated from the disconnect member 28 and a second disconnect position DP2 in which the disconnectable component 36 of the input hub 34 is engaged with the disconnect member 28. Figure 3 The step 106 of moving the disconnecting member 28 from the first disconnecting position DP1 to the second disconnecting position DP2 is indicated in FIG. 1 by the shifting pattern, in particular by the element D.

[0078] The method 100 further includes step 108 of moving the selectable one-way clutch 26 from the second clutch position X / O to a third clutch position O / O in which the selectable one-way clutch 26 is configured to prevent torque from being transmitted from the input member 20 through one of the first gear ratio 14 and the second gear ratio 16 in either the first rotational direction D1 or the second rotational direction D2 to shift torque from being transmitted from the input member 20 through one of the first gear ratio 14 and the second gear ratio 16 to being transmitted from the input member 20 through the other of the first gear ratio 14 and the second gear ratio 16. Figure 3Step 108 of moving the selectable one-way clutch 26 from the second clutch position X / O to the third clutch position O / O is indicated in FIG. 1 by the shift schedule, in particular by the element F.

[0079] In one embodiment, the step 102 of moving the selectable one-way clutch 26 from the first clutch position X / X to the second clutch position X / O precedes the step 104 of moving the plurality of clutch plates 40 from the engaged position ENG to the disengaged position D-ENG. In addition, the step 104 of moving the plurality of clutch plates 40 from the engaged position ENG to the disengaged position D-ENG may precede the step 106 of moving the disconnecting member 28 from the first disconnecting position DP1 to the second disconnecting position DP2. In this way, the disconnecting member 28 may smoothly engage the disconnectable component 36 of the input hub 34 because the clutch plates 40 in the disengaged position D-ENG rotatably decouple the input member 20 from the output member 30.

[0080] In addition, the step 106 of moving the disconnect member 28 from the first disconnect position DP1 to the second disconnect position DP2 may precede the step 108 of moving the selectable one-way clutch 26 from the second clutch position X / O to the third clutch position O / O. The method 100 may further include the step 110 of: Figure 3 In the embodiment indicated by the shifting pattern (particularly by element E), the plurality of clutch plates 40 are moved from the disengaged position D-ENG to the engaged position ENG. In other words, the clutch plates 40 can be reengaged. In an embodiment in which the clutch plates 40 are normally closed, the step 110 of moving the clutch plates 40 from the disengaged position D-ENG to the engaged position ENG causes the clutch plates 40 to be stationary and the torque can be transmitted to the other of the first gear ratio 14 and the second gear ratio 16 through the shift assembly 32. In this way, the torque is allowed to be transmitted to the other of the first gear ratio 14 and the second gear ratio 16 through the shift assembly 32. As discussed above in step 108, the selectable one-way clutch 26 can then be moved from the second clutch position X / O to the third clutch position O / O to rotatably decouple the input member 20 from the selectable one-way clutch 26 and prevent the torque from being transmitted through one of the first gear ratio 14 and the second gear ratio 16.

[0081] The step 106 of moving the disconnecting member 28 from the first disconnecting position DP1 to the second disconnecting position DP2 may precede the step 110 of moving the plurality of clutch plates 40 from the disengaged position D-ENG to the engaged position ENG. In other words, the disconnecting member 28 may be engaged with the disconnectable component 36 of the input hub 34 before the clutch plates 40 are reengaged. Reengaging the clutch plates 40 after the disconnecting member 28 is in the second disconnecting position DP2 allows the input member 20 and the output member 30 to be smoothly rotatably coupled, thus allowing torque to be transmitted through the other of the first gear ratio 14 and the second gear ratio 16. Figure 3 The shift schedule in indicates by element A that torque is allowed to be transmitted through one of the first gear ratio 14 and the second gear ratio 16 , and by element G that torque is allowed to be transmitted through the other of the first gear ratio 14 and the second gear ratio 16 .

[0082] It will be appreciated that one of the first gear ratio 14 and the second gear ratio 16 may be the first gear ratio 14 or the second gear ratio 16. It will also be appreciated that the other of the first gear ratio 14 and the second gear ratio 16 may be the first gear ratio 14 or the second gear ratio 16. In other words, the selectable one-way clutch 26 may be configured to transmit torque through the first gear ratio 14, or may be configured to transmit torque through the second gear ratio 16. Thus, the shift assembly 32 may be configured to transmit torque through the corresponding first gear ratio 14 or the second gear ratio 16. In embodiments where the selectable one-way clutch 26 is configured to transmit torque through the first gear ratio 14, the shift assembly 32 is configured to transmit torque through the second gear ratio 16. Alternatively, in embodiments where the selectable one-way clutch is configured to transmit torque through the second gear ratio 16, the shift assembly 32 is configured to transmit torque through the first gear ratio 14. It will also be appreciated that the torque multiplication or torque reduction through the first gear ratio 14 may be higher or may be lower than the torque multiplication or torque reduction through the second gear ratio 16.

[0083] The method 200 of operating the shift system 18 for the vehicle transmission 10 includes the step 202 of engaging the clutch 25 to operatively couple one of the first gear ratio 14 and the second gear ratio 16 to the input member 20, as determined by Figure 3denoted by elements A and B in . The method 200 further includes a step 204 of moving the disconnecting member 28 from a first disconnecting position DP1 to a second disconnecting position DP2, wherein the disconnectable component 36 of the input hub 34 is disengaged from the disconnecting member 28, and wherein the disconnectable component 36 of the input hub 34 is engaged with the disconnecting member 28 to operatively couple the other of the first gear ratio 14 and the second gear ratio 16 to the input member 20 through the shift assembly 32. The step 204 of moving the disconnecting member 28 from the first disconnecting position DP1 to the second disconnecting position DP2 is indicated by Figure 3 The element PS in is indicated and is referred to herein as a “park shift”.

[0084] Steps 202, 204 of engaging the clutch 25 and moving the disconnect member 28 from the first disconnect position DP1 to the second disconnect position DP2 are performed such that the clutch 25 is operatively coupled to one of the first gear ratio 14 and the second gear ratio 16 while the shift assembly 32 is operatively coupled to the other of the first gear ratio 14 and the second gear ratio 16, thereby preventing torque from being transmitted through either of the first gear ratio 14 and the second gear ratio 16 of the vehicle transmission 10 to park the vehicle. The results of steps 202, 204 of engaging the clutch 25 and moving the disconnect member 28 from the first disconnect position DP1 to the second disconnect position DP2 are as follows: Figure 3 The element P in is indicated and is referred to herein as “parked” or “parked”.

[0085] The method 200 may also be performed such that: when the clutch 25 is operatively coupled to one of the first gear ratio 14 and the second gear ratio 16 while the shift assembly 32 is operatively coupled to the other of the first gear ratio 14 and the second gear ratio 16, torque is prevented from being transmitted from the input member 20 or the output member 30 through either of the first gear ratio 14 and the second gear ratio 16. In other words, the method 200 may prevent torque from being transmitted from the input member 20 to the output member 30 through either of the first gear ratio 14 and the second gear ratio 16. In addition, the method 200 may prevent torque from being transmitted from the output member 30 to the input member 20 through either of the first gear ratio 14 and the second gear ratio 16. In this way, the method 200 may rotationally lock the input member 20 and the output member 30 relative to each other.

[0086] In one embodiment, the first gear ratio 14 and the second gear ratio 16 are opposing one another. In other words, torque transfer through the first gear ratio 14 prevents torque transfer through the second gear ratio 16, and torque transfer through the second gear ratio 16 prevents torque transfer through the first gear ratio 14. In addition, when the clutch 25 is operatively coupled to one of the first gear ratio 14 and the second gear ratio 16 while the shift assembly 32 is operatively coupled to the other of the first gear ratio 14 and the second gear ratio 16, there may be no relative motion between the input member 20 and the output member 30.

[0087] When the clutch 25 is operatively coupled to one of the first gear ratio 14 and the second gear ratio 16 while the shift assembly 32 is operatively coupled to the other of the first gear ratio 14 and the second gear ratio 16, the method 200 can result in no relative motion between the clutch 25 and the shift assembly 32. In other words, throughout the period during which the vehicle is held in park, the clutch 25 and the shift assembly 32 can be static relative to each other. The clutch 25 is statically held in engagement, and the shift assembly 32 is statically held so that the clutch plate 40 is in the engaged position and the disconnect member 28 is in the second disconnected position DP2.

[0088] The clutch 25 can be disposed about the input member 20 and at least partially rotatably coupled to the input member 20, as shown in FIG1. ​​In embodiments where the clutch 25 has an inner race 44 and an outer race 46, particularly in embodiments where the clutch 25 is a selectable one-way clutch 26, the inner race 44 can be rotatably coupled to the input member 20. The inner race 44 can be splined, bolted, or otherwise mechanically fixed to the input member 20 such that the inner race 44 is rotatably coupled to the input member 20. However, the outer race 46 can be selectively rotatably fixed to the inner race 44 by a pawl 48 or a plurality of pawls 50.

[0089] In embodiments where the vehicle transmission 10 includes a countershaft 62, the clutch 25 may be disposed about the countershaft 62 and at least partially rotatably coupled to the countershaft 62, as shown in FIG. 2. In embodiments where the clutch 25 has an inner race 44 and an outer race 46, particularly in embodiments where the clutch 25 is a selectable one-way clutch 26, the inner race 44 may be rotatably coupled to the countershaft 62. The inner race 44 may be splined, bolted, or otherwise mechanically fixed to the countershaft 62 such that the inner race 44 is rotatably coupled to the countershaft 62. However, the outer race 46 may be selectively rotatably fixed to the inner race 44 by a pawl 48 or a plurality of pawls 50.

[0090] The disconnect member 28 may be disposed around the input member 20 and axially aligned with the input member 20. In this embodiment, the shift assembly 32 may be axially aligned with the input member 20, and the input member 20 may directly transfer torque through the shift assembly 32 without requiring additional components to transfer torque from the input member 20 to the shift assembly 32. In addition, since the disconnect member 28 is disposed around the input member 20 and axially aligned with the input member 20, the size of the vehicle transmission 10 may be reduced.

[0091] The plurality of clutch plates 40 may be axially spaced apart from the disconnect member 28 such that the disconnect member 28 is disposed between the first gear ratio 14 and the plurality of clutch plates 40. Although not required, the arrangement between the plurality of clutch plates 40, the disconnect member 28, and the first gear ratio 14 results in efficient use of space within the vehicle transmission 10 because both the first gear ratio 14 and the disconnect member 28 may be partially disposed around the input member 20, and the plurality of clutch plates 40 may be disposed proximate one of the first end 22 and the second end 24 of the input member 20.

[0092] The second gear ratio 16 may be axially spaced from the disconnect 28 such that the disconnect 28 is disposed between the first gear ratio 14 and the second gear ratio 16. Although not required, the arrangement between the disconnect 28, the first gear ratio 14, and the second gear ratio 16 results in the disconnect 28, as a component of the shift assembly 32, being able to assist in being operatively coupled to one of the first gear ratio 14 and the second gear ratio 16 while the clutch 25 is operatively coupled to the other of the first gear ratio 14 and the second gear ratio 16, thereby preventing torque from being transmitted through either of the first gear ratio 14 and the second gear ratio 16 of the vehicle transmission 10 to park the vehicle.

[0093] like Figure 3 Indicated by element C, method 200 may further include step 206: moving the plurality of clutch plates from a disengaged position D-ENG in which the clutch plates 40 are disengaged from each other to an engaged position ENG in which the clutch plates 40 are engaged with each other. Figure 3Indicated by element PS in the figure, the step 206 of moving the plurality of clutch plates 40 from the disconnected position D-ENG to the engaged position ENG may precede the step 204 of moving the disconnect member 28 from the first disconnected position DP1 to the second disconnected position DP2. By moving the clutch plates 40 from the disconnected position D-ENG to the engaged position ENG, torque may be transmitted through the shift assembly 32 when the disconnect member 28 is in the second disconnected position DP2. Alternatively, it will be understood that moving the disconnect member 28 from the first disconnected position DP1 to the second disconnected position DP2 may precede the step of moving the plurality of clutch plates 40 from the disconnected position D-ENG to the engaged position ENG. By moving the disconnect member 28 from the first disconnected position DP1 to the second disconnected position DP2 before the plurality of clutch plates 40 are moved from the disconnected position D-ENG to the engaged position ENG, upon completion of the step 206 of moving the clutch plates 40 from the disconnected position D-ENG to the engaged position ENG, the other of the first gear ratio 14 and the second gear ratio 16 is operatively coupled through the shift assembly 32.

[0094] It will be appreciated that the clutch 25 used in the method 200 may be a selectable one-way clutch 26. However, it will also be appreciated that the clutch 25 may be any of the clutches disclosed herein, including but not limited to: another shift assembly as described herein, a dry friction clutch, a wet friction clutch, a single plate clutch, a multi-plate clutch, a cone clutch, a dog clutch, or a centrifugal clutch.

[0095] In an embodiment where the clutch 25 is a selectable one-way clutch 26, the step 202 of engaging the clutch 25 to operatively couple one of the first gear ratio 14 and the second gear ratio 16 to the input member 20 can be further defined as a step 208 of moving the selectable one-way clutch 26 from the third clutch position O / O to the first clutch position X / X, as Figure 3 denoted by elements G to P in . It will be appreciated that in embodiments where the clutch 25 is a selectable one-way clutch 26, the step 202 of engaging the clutch 25 may be further defined as a step 210 of moving the selectable one-way clutch 26 from a third clutch position O / O to a second clutch position X / O, and from the second clutch position X / O to the first clutch position X / X. In other words, the selectable one-way clutch 26 may be in a free / free configuration, moved to a locked / free configuration, and then moved to a locked / locked configuration. In the locked / locked configuration, one of the first gear ratio 14 and the second gear ratio 16 is operatively coupled to the selectable one-way clutch 26.

[0096] In an embodiment where the clutch 25 is a selectable one-way clutch 26, the step 210 of moving the selectable one-way clutch 26 from the third clutch position O / O to the second clutch position X / O and from the second clutch position X / O to the first clutch position X / X may precede the step 204 of moving the disconnect member 28 from the first disconnect position DP1 to the second disconnect position DP2. In other words, although not required, the selectable one-way clutch 26 may be in a locked / free configuration and moved to the locked / locked position before moving the disconnect member 28 from the first disconnect position DP1 to the second disconnect position DP2. Therefore, in this embodiment, the selectable one-way clutch 26 is operably coupled to one of the first gear ratio 14 and the second gear ratio 16 before the shift assembly 32 is operably coupled to the other of the first gear ratio 14 and the second gear ratio 16. However, it will be understood that the shift assembly 32 may be operably coupled to one of the first gear ratio 14 and the second gear ratio 16 before the selectable one-way clutch 26 is operably coupled to the other of the first gear ratio 14 and the second gear ratio 16. To this end, the disconnect member 28 may be moved from the first disconnect position DP1 to the second disconnect position DP2 before moving the selectable one-way clutch 26 from the second clutch position X / O to the first clutch position X / X.

[0097] It will be appreciated that the step 206 of moving the plurality of clutch plates 40 from the disengaged position D-ENG to the engaged position ENG may be before the step 210 of moving the selectable one-way clutch 26 from the third clutch position O / O to the second clutch position X / O and from the second clutch position X / O to the first clutch position X / X. As discussed above, in the engaged position ENG, the plurality of clutch plates 40 may be normally closed and stationary. However, the disconnect member 28 may be stationary in either the first disconnected position DP1 or the second disconnected position DP2. Therefore, when the disconnect member 28 is in the first disconnected position DP1 and the plurality of clutch plates 40 are in the engaged position ENG, the shift assembly 32 may be stationary.

[0098] Thus, before the selectable one-way clutch 26 moves from the second clutch position X / O to the first clutch position X / X (i.e., from a locked / free configuration to a locked / locked configuration), the shift assembly 32 can be placed stationary, thereby operably coupling one of the first gear ratio 14 and the second gear ratio 16 to the selectable one-way clutch 26. With the disconnect member 28 in the first disconnect position DP1 and the selectable one-way clutch 26 in the first clutch position X / X (i.e., a locked / locked configuration), the vehicle is in either first gear or second gear.

[0099] The vehicle may then be placed at rest so that the vehicle has no forward or reverse movement. The method 200 may then be employed, including a parking shift through step 204 by moving the disconnect member 28 from the first disconnect position DP1 to the second disconnect position DP2, so that the vehicle is parked as a result. The disconnect member 28 may be moved from the first disconnect position DP1 to the second disconnect position DP2 without having to move the plurality of clutch plates 40 from the engaged position ENG to the disengaged position D-ENG before moving the disconnect member 28 from the first disconnect position DP1 to the second disconnect position DP2, because the vehicle is stationary.

[0100] More specifically, because no torque is transmitted to one of the first gear ratio 14 and the second gear ratio 16 through the selectable one-way clutch 26, the disconnect member 28 can be moved from the first disconnect position DP1 to the second disconnect position DP2, and the other of the first gear ratio 14 and the second gear ratio 16 can be operably coupled through the shift assembly 32. When both the first gear ratio 14 and the second gear ratio 16 are operably coupled to the selectable one-way clutch 26 and the shift assembly 32, respectively, since torque cannot be transmitted through any one of the first gear ratio 14 and the second gear ratio 16 or through both of the first gear ratio 14 and the second gear ratio 16, the vehicle is parked, and movement of the vehicle is prevented. In other words, because the vehicle cannot be in the first gear and the second gear at the same time when torque is transmitted through any one of the first gear ratio 14 and the second gear ratio 16, the vehicle is prevented from moving when parked.

[0101] The present invention has been described in an illustrative manner, and it will be understood that the terminology used is intended to have the nature of words of description rather than limitation. In light of the above teachings, many modifications and variations of the present invention are possible, and the present invention may be practiced in ways other than those specifically described.

Claims

1. A method of operating a shifting system for a vehicle transmission, the vehicle transmission having: a gear set including a first gear ratio and a second gear ratio, wherein the vehicle transmission is disposed in a vehicle, and wherein the shifting system comprises: an input member extending along a first axis between a first end and a second end spaced from the first end, wherein the input member is rotatable about the first axis; a clutch coupled to the input member and configured to selectively allow torque to be transferred from the input member through one of the first gear ratio and the second gear ratio of the gear set; a disconnect member coupled to the input member; an output member spaced apart from the input member, the output member selectively rotatable with the input member about the first axis to selectively transmit torque through the other of the first gear ratio and the second gear ratio of the gear set; and a shift assembly to selectively rotatably couple the input member and the output member, the shift assembly comprising: an input hub coupled to the input member, wherein the input hub has a disconnectable component engageable with the disconnect member, and wherein the input hub has a clutch engaging component; a plurality of clutch plates coupled to the clutch engaging component of the input hub; and a clutch plate carrier coupled to the plurality of clutch plates and coupled to the output member to transfer torque from the clutch engaging component of the input hub to the output member through the plurality of clutch plates and the clutch plate carrier, the method comprising: engaging the clutch to operatively couple one of the first gear ratio and the second gear ratio to the input member; and moving the disconnect member from a first disconnect position in which the disconnectable component of the input hub is disengaged from the disconnect member to a second disconnect position in which the disconnectable component of the input hub is engaged with the disconnect member to operatively couple the other of the first gear ratio and the second gear ratio to the input member through the shift assembly; wherein the steps of engaging the clutch and moving the disconnect member from the first disconnected position to the second disconnected position are performed such that the clutch is operatively coupled to one of the first gear ratio and the second gear ratio while the shift assembly is operatively coupled to the other of the first gear ratio and the second gear ratio, thereby preventing torque from being transmitted through either of the first gear ratio and the second gear ratio of the vehicle transmission to park the vehicle.

2. The method of claim 1 , wherein the clutch is operatively coupled to one of the first gear ratio and the second gear ratio while the shift assembly is operatively coupled to the other of the first gear ratio and the second gear ratio, preventing torque from being transmitted from either the input member or the output member through either the first gear ratio and the second gear ratio.

3. A method according to any one of the preceding claims, wherein torque transfer through the first gear ratio prevents torque transfer through the second gear ratio, and torque transfer through the second gear ratio prevents torque transfer through the first gear ratio.

4. The method of any one of claims 1 and 2, wherein there is no relative motion between the input member and the output member when the clutch is operatively coupled to one of the first gear ratio and the second gear ratio while the shift assembly is operatively coupled to the other of the first gear ratio and the second gear ratio.

5. The method of any one of claims 1 and 2, wherein there is no relative motion between the clutch and the shift assembly when the clutch is operatively coupled to one of the first gear ratio and the second gear ratio while the shift assembly is operatively coupled to the other of the first gear ratio and the second gear ratio.

6. The method of any one of claims 1 and 2, wherein the clutch is disposed about the input member and is at least partially rotatably coupled to the input member.

7. The method of any one of claims 1 and 2, wherein the vehicle transmission includes a layshaft spaced apart from the input member and rotatable about a second axis, wherein the clutch is disposed about the layshaft and is at least partially rotatably coupled to the layshaft.

8. The method of any one of claims 1 and 2, wherein the disconnect element is disposed about the input member and is axially aligned with the input member.

9. The method of any one of claims 1 and 2, wherein the plurality of clutch plates are axially spaced apart from the disconnect member such that the disconnect member is disposed between the first gear ratio and the plurality of clutch plates.

10. The method of any one of claims 1 and 2, wherein the second gear ratio is axially spaced from the disconnect member such that the disconnect member is disposed between the first gear ratio and the second gear ratio.

11. The method of any one of claims 1 and 2, wherein the shift assembly includes a biasing member coupled to the plurality of clutch plates and configured to bias the plurality of clutch plates toward an engaged position in which the clutch plates engage one another.

12. The method according to any one of claims 1 and 2, further comprising the steps of: The plurality of clutch plates are moved from a disengaged position in which the clutch plates are disengaged from one another, to an engaged position in which the clutch plates are engaged with one another.

13. The method according to claim 12, wherein: The step of moving the multiple clutch plates from the disengaged position to the engaged position precedes the step of moving the disconnect member from the first disconnected position to the second disconnected position, or the step of moving the disconnect member from the first disconnected position to the second disconnected position precedes the step of moving the multiple clutch plates from the disengaged position to the engaged position.

14. The method of any one of claims 1 and 2, wherein the clutch is a selectable one-way clutch movable between: a first clutch position wherein the selectable one-way clutch is configured to allow torque to be transmitted from the input member through one of the first gear ratio and the second gear ratio of the gear set in either a first rotational direction or a second rotational direction opposite the first rotational direction; a second clutch position wherein the selectable one-way clutch is configured to allow torque to be transferred in the first rotational direction from the input member through one of the first gear ratio and the second gear ratio of the gear set and to prevent torque from being transferred in the second rotational direction from the input member through one of the first gear ratio and the second gear ratio of the gear set; as well as A third clutch position wherein the selectable one-way clutch is configured to prevent torque from being transmitted from the input member through one of the first gear ratio and the second gear of the gear set in either the first rotational direction or the second rotational direction.

15. The method according to claim 14, wherein: The step of engaging the clutch to operatively couple one of the first gear ratio and the second gear ratio to the input member is further defined as moving the selectable one-way clutch from the third clutch position to the first clutch position.

16. The method according to claim 15, wherein: Engaging the clutch to operatively couple one of the first gear ratio and the second gear to the input member is further defined by moving the selectable one-way clutch from the third clutch position to the second clutch position and from the second clutch position to the first clutch position.

17. The method according to claim 16, wherein: The step of moving the disconnect member from the first disconnect position to the second disconnect position is preceded by the step of moving the selectable one-way clutch from the third clutch position to the second clutch position and from the second clutch position to the first clutch position.

18. The method according to claim 14, further comprising the steps of: The multiple clutch plates are moved from a disengaged position in which the clutch plates are disengaged from each other to an engaged position in which the clutch plates are engaged with each other, wherein the step of moving the multiple clutch plates from the disengaged position to the engaged position is preceded by the step of moving the selectable one-way clutch from the third clutch position to the second clutch position and from the second clutch position to the first clutch position.

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