WO2018220561A1

WO2018220561A1 - Shift fork lock system for a transmission

Info

Publication number: WO2018220561A1
Application number: PCT/IB2018/053865
Authority: WO
Inventors: Daniel Norheim; Bjørn S. IVERSEN; Kristian Flateland AHLBERG
Original assignee: Ka Group Ag
Priority date: 2017-05-30
Filing date: 2018-05-30
Publication date: 2018-12-06

Abstract

A shift fork lock system for a transmission includes a shift rail extending along a rail axis. The shift rail is movable axially along and rotatably around the rail axis. The shift fork lock system further includes a shift fork having an internal surface defining a bore along the rail axis. The shift rail extends through the bore and is movable axially and rotatably relative to the shift fork when the shift fork is in a decoupled configuration. The shift rail is rotatable to a first rotational position and a coupled configuration such that the shift fork is coupled to and movable with the shift rail along the rail axis. The shift rail is rotatable to a second rotational position and the decoupled configuration such that the shift fork is decoupled from the shift rail to facilitate movement of the shift rail independent of the shift fork along the rail axis.

Description

SHIFT FORK LOCK SYSTEM FOR A TRANSMISSION

RELATED APPLICATIONS

[0001] This application claims priority to and the benefit of U.S. Provisional Patent Application No. 62/512,558, filed on May 30, 2017, the entire contents of which are hereby incorporated by reference.

1. Field of the Invention

[0001] The present disclosure relates to a shift fork lock system for a transmission.

2. Description of Related Art

[0002] Transmissions for vehicles commonly use a multispeed gearset to provide mechanical advantage to rotational motion from an engine to the driven wheels of the vehicle. One example of a multispeed gearset includes gears and rings between the gears that facilitate changing between different gears (or "speeds") of the multispeed gearset.

[0003] To move the rings, the multispeed gearset includes forks that respectively engage the rings. Commonly, the multispeed gearset includes several shafts (each having a shift fork coupled thereto), with shift forks having long extensions from the respective shafts in order to reach the rings. Although effective in facilitating movement of the rings, the shafts and shift forks are space consuming, which results in packaging issues within the transmission. As such, there remains a need to provide an improved mechanism for changing between different gears of a transmission.

SUMMARY OF THE INVENTION AND ADVANTAGES

[0004] The subject invention provides for a shift fork lock system for a transmission, with the shift fork lock system including a shift rail extending along a rail axis. The shift rail is movable axially along and rotatably around the rail axis. The shift rail has an external surface and defines a recess extending below the external surface.

[0005] The shift fork lock system further includes a shift fork defining a bore along the axis. The shift rail extends through the bore. The shift rail is movable axially and rotatably relative to the shift fork when the shift fork is in a decoupled configuration.

[0006] The shift fork lock system further includes a pin coupled to and movable relative to the shift fork. The pin has first and second ends. The first end engages the external surface of the shift rail in the decoupled configuration and is disposed in the recess in a coupled configuration.

[0007] The shift fork lock system further includes a biasing member abutting and biasing the first end of the pin toward the rail axis and a locking plate extending along the rail axis and defining a cavity configured to receive the second end of the pin.

[0008] The shift rail is rotatable to a first rotational position, with the first end of the pin disposed in the recess of the shift rail in the coupled configuration and the second end of the pin spaced from the locking plate such that the shift fork is coupled to and movable with the shift rail along the rail axis. Furthermore, the shift rail is rotatable to a second rotational position, with the first end of the pin engaged with and slidable along the external surface of the shift rail in the decoupled configuration and the second end of the pin disposed in the cavity of the locking plate such that the shift fork is decoupled from the shift rail and retained by the locking plate to facilitate movement of the shift rail independent of the shift fork along the rail axis.

[0009] The subject invention also provides for a shift fork lock system for a transmission, with the shift fork lock system including a shift rail extending along a rail axis. The shift rail is movable axially along and rotatably around the rail axis. The shift rail has a protrusion extending radially from the rail axis to an engagement surface.

[0010] The shift fork lock system further includes a shift fork defining a bore along the axis. The shift rail extends through the bore and is movable axially and rotatably relative to the shift fork when the shift fork is in a decoupled configuration. The shift fork has an external surface and defines first and second voids extending below the external surface. The first and second voids open to one another such that the protrusion is disposed within and movable between the first and second voids.

[0011] The shift fork lock system further includes a locking plate extending along the rail axis and defining a cavity and a pin coupled to and movable relative to the locking plate within the cavity. The pin has first and second ends. The first end engages at least one of the protrusion of the shift rail and the external surface of the shift fork in a coupled configuration and is disposed within the first void of the shift fork in a decoupled configuration.

[0012] The shift fork lock system further includes a biasing member abutting the second end of the pin and biasing the pin toward the rail axis. The shift rail is rotatable to a first rotational position to dispose the protrusion in the first void and in engagement with the shift fork in the coupled configuration. The engagement surface of the protrusion moves the pin away from the rail axis against the bias of the biasing member to slidably dispose the first end of the pin along the external surface and the engagement surface such that the shift fork is coupled to and movable with the shift rail along the rail axis. The shift rail is rotatable to a second rotational position to dispose the protrusion in the second void in the decoupled configuration. The first end of the pin is disposed in the first void and is in engagement with the shift fork. The protrusion is movable within the second void along the rail axis such that the shift fork is decoupled from the shift rail and is retained by the locking plate to facilitate movement of the shift rail independent of the shift fork along the rail axis.

[0013] The subject invention also provides for a shift fork lock system for a transmission, with the shift fork lock system including a shift rail extending along a rail axis. The shift rail is movable axially along and rotatably around the rail axis. The shift rail has an external surface and defines a groove extending below the external surface and having first and second regions. The second region extends further below the external surface than the first region.

[0014] The shift fork lock system further includes a shift fork having an internal surface defining a bore along the rail axis. The shift rail extends through the bore and is movable axially and rotatably relative to the shift fork when the shift fork is in a decoupled configuration. The shift fork defines a detent extending below the internal surface away from the shift rail.

[0015] The shift fork lock system further includes a ball coupled to and movable relative to the shift rail. The ball is disposed in the first region of the groove in a coupled configuration and in the second region of the groove in the decoupled configuration.

[0016] The shift rail is rotatable to a first rotational position with the ball disposed in both the detent and the first region of the groove in the coupled configuration such that the shift fork is coupled to and movable with the shift rail along the rail axis. The shift rail is rotatable to a second rotational position with the ball disposed in the second region of the groove and Tollable along the internal surface of the shift fork such that the shift fork is decoupled from the shift rail to facilitate movement of the shift rail independent of the shift fork along the rail axis.

[0017] Accordingly, the shift fork lock systems provide the advantage of selectively coupling and decoupling the shift fork to shift rail, which in-turn facilitates the disposition of a plurality of shift forks to the shift rail. Disposing the plurality of shift forks on the single shift rail improves the packaging of the shift forks, reduces the weight of the transmission, and uses a common, centralized component coupled to all of the plurality of shift forks that moves the shift forks, which ensures the correct selection of gears of the transmission.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Advantages of the subject invention will be readily appreciated, as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings.

[0019] Figure 1 is a perspective view of a multispeed transmission gearset and shift fork lock system, shown in phantom.

[0020] Figure 2 is a perspective view of a shift fork lock system having shift forks, a locking plate, and a shift rail.

[0021] Figure 3 is a perspective view of the shift fork lock system shown in Figure 2, with the shift forks and the locking plate in phantom.

[0022] Figure 4 is a section view of the shift fork lock system shown in Figure 3.

[0023] Figure 5A is a cross-sectional perspective view of the shift fork lock system taken along line 5-5 in Figure 4 showing a pin in a coupled configuration.

[0024] Figure 5B is a cross-sectional perspective view of the shift fork lock system taken along line 5-5 in Figure 4 showing the pin in a decoupled configuration.

[0025] Figure 6 is a perspective view of a shift fork lock system showing a bottom wall having an arcuate configuration.

[0026] Figure 7 is a cross-sectional perspective view of the shift fork lock system taken along line 7-7 in Figure 6. [0027] Figure 8 is a perspective view of a shift fork lock system showing a locking plate defining a cavity having longitudinal and lateral regions.

[0028] Figure 9A is a cross-sectional perspective view of the shift fork lock system taken along line 9-9 in Figure 8 showing a pin in a coupled configuration.

[0029] Figure 9B is a cross-sectional perspective view of the shift fork lock system taken along line 9-9 in Figure 8 showing the pin in a decoupled configuration.

[0030] Figure 10 is a perspective view of a shift fork lock system having shift forks each defining first and second voids, a locking plate, and a shift rail.

[0031] Figure 11 is a perspective view of the shift forks and the shift rail shown in Figure 10, with one of the shift forks coupled to the shift rail in a coupled configuration.

[0032] Figure 12 is a perspective view of the shift forks and the shift rail shown in Figure 10, with one of the shift forks coupled to the shift rail in the coupled configuration and moved away from the other shift forks along the rail axis.

[0033] Figure 13 is a cross-sectional perspective view of a shift fork lock system showing a shift forks defining detents, a shift rail defining a groove, and balls.

[0034] Figure 14 is a perspective view of the shift fork lock system shown in Figure 13, with the shift forks in phantom.

[0035] Figure 15 is a perspective view of the shift rail of the shift fork lock system shown in Figure 13.

[0036] Figure 16 is a cross-sectional perspective view of the shift fork lock system taken along line 16-16 in Figure 14. DETAILED DESCRIPTION OF THE INVENTION

[0037] Referring now to the drawings, where like numerals indicate like or corresponding parts throughout the several views, a transmission for a vehicle is generally shown in Figure 1. While the transmission is adapted for use with vehicles such as automotive passenger or commercial vehicles, it will be appreciated that the transmission could be used in connection with any type of vehicle, such as heavy-duty trucks, trains, airplanes, ships, construction vehicles or equipment, military vehicles, or any other type of vehicle that utilizes a transmission or torque transfer system.

[0038] The transmission includes a multispeed transmission gearset 22 that transmits and provides mechanical advantage to rotational motion from a prime mover of the vehicle (such as an engine or a motor) to a driven wheel of the vehicle. One example of a multispeed transmission gearset 22 is shown in Figure 1. The gearset 22 includes a first shaft 24, a second shaft 26, a plurality of gears 28 coupled to or otherwise supported by the shafts 24, 26, and rings 30 interposed between certain gears 28 to facilitate changing between different gears (or "speeds") of the multispeed transmission gearset 22.

[0039] The transmission further includes a shift fork lock system 32, 72, 104 that facilitates shifting between the gears 28 of the multispeed transmission gearset 22. As will be appreciated from the subsequent description below, the shift fork lock system 32, 72, 104 of the present invention is adapted for use with any suitable type of multispeed transmission that adjusts rotational speed and torque between the first shaft 24 and the second shaft 26. By way of non-limiting example, the multispeed transmission could be a conventional automatic that employs a torque converter, a modern automatic that employs one or more electronically and/or hydraulically actuated clutches, or a conventional manual with a manually actuated clutch. [0040] In Figure 1, the shift fork lock system 32, 72, 104 is shown in phantom and illustrates the general location of the shift fork lock system 32, 72, 104 in the transmission and the general engagement of the shift fork lock system 32, 72, 104 with the multispeed transmission gearset 22. As such, all of the embodiments of the shift fork lock system 32, 72, 104 described herein may be adapted for use with the multispeed transmission gearset 22 shown in Figure 1. Furthermore, all of the embodiments of the shift fork lock system 32, 72, 104 described herein may be modified for use with any multispeed transmission gearset not explicitly shown herein.

[0041] As shown in Figure 1, the multispeed transmission gearset 22 includes at least one ring 30 and the shift fork lock system 32, 72, 104 includes at least one shift fork 40, 80, 116 coupled to the ring 30. The ring 30 (sometimes referred to as a "collar," a "synchronizer," or a "synchro") moves concurrently with the shift fork 40, 80, 116 to facilitate selectively coupling and decoupling gears 28 of the gearset 22 to shift between transmission "speeds".

[0042] The present invention provides an embodiment of the shift fork lock system 32 that includes a shift rail 34 extending along a rail axis Rl, as shown in Figures 2-9B. The shift rail 34 is movable axially along and rotatably around the rail axis Rl. The shift rail 34 has an external surface 36 and defines a recess 38 extending below the external surface 36, as shown in Figure 3-7, 9A, and 9B.

[0043] The shift fork lock system 32 further includes a shift fork 40 defining a bore 42 along the axis. The shift rail 34 extends through the bore 42. The shift rail 34 is movable axially and rotatably relative to the shift fork 40 when the shift fork 40 is in a decoupled configuration. [0044] The shift fork lock system 32 further includes a pin 44 coupled to and movable relative to the shift fork 40. The pin 44 has first and second ends 46, 48. The first end 46 engages the external surface 36 of the shift rail 34 in the decoupled configuration and is disposed in the recess 38 in a coupled configuration.

[0045] The shift fork lock system 32 further includes a biasing member 50 abutting and biasing the first end 46 of the pin 44 toward the rail axis Rl and a locking plate 52 extending along the rail axis Rl and defining a cavity 54 configured to receive the second end 48 of the pin 44.

[0046] The shift rail 34 is rotatable to a first rotational position, with the first end 46 of the pin 44 disposed in the recess 38 of the shift rail 34 in the coupled configuration and the second end 48 of the pin 44 spaced from the locking plate 52 such that the shift fork 40 is coupled to and movable with the shift rail 34 along the rail axis Rl. Furthermore, the shift rail 34 is rotatable to a second rotational position, with the first end 46 of the pin 44 engaged with and slidable along the external surface 36 of the shift rail 34 in the decoupled configuration and the second end 48 of the pin 44 disposed in the cavity 54 of the locking plate 52 such that the shift fork 40 is decoupled from the shift rail 34 and retained by the locking plate 52 to facilitate movement of the shift rail 34 independent of the shift fork 40 along the rail axis Rl.

[0047] Said differently, when the shift rail 34 is moved to the first rotational position, the shift fork 40 is coupled to and moves with shift rail 34 along the rail axis Rl. When the shift rail 34 is moved to the second rotational position, the shift fork 40 is coupled to the locking plate 52 and remains stationary with the locking plate 52 as the shift rail 34 moves along the rail axis Rl. Accordingly, rotation of the shift rail 34 between the first and second rotational positions allow for selective engagement and axial movement of the shift fork 40 to shift between transmission "speeds".

[0048] As shown in the Figures 2-4 and 6-8, the shift fork 40, the pin 44, the biasing member 50, the recess 38, and the cavity 54 may be further defined as a plurality of shift forks 40, a plurality of pins 44, a plurality of biasing members 50, a plurality of recesses 38, and a plurality of cavities 54 individually corresponding to one another, with each of the shift forks 40 configured to alternate between coupled and decoupled configurations. More specifically, as shown in Figure 1 , the plurality of shift forks 40 may each individually engage a respective ring 30. As shown in Figures 2-4 and 6-8, the plurality of shift forks 40 may each be alternated between the coupled and decoupled configurations independent of one another. As such, one or more of the shift forks 40 may be in the coupled configuration for a given rotation of the shift rail 34 and one or more of the shift forks 40 may be in the decoupled configuration for a given rotation of the shift rail 34. Therefore, depending on the rotation of the shift rail 34 certain shift fork(s) 40 may move axially with the shift rail 34 to move the respective ring(s) 30 of the transmission while certain shift fork(s) 40 may be retained by the locking member to prevent movement of the respective ring(s) 30 of the transmission. The description below describes one shift fork 40 and the mechanisms through which shift fork 40 alternates between the coupled and decoupled configurations. One having skill in the art will appreciate that the description may be applicable to each of the plurality of shift forks 40.

[0049] In the embodiment shown in Figures 2-9B, the locking plate 52 is fixed along the rail axis Rl. However, one having skill in the art will appreciate may be configured to move along the rail axis Rl (either with the shift rail 34 or independent of the shift rail 34). [0050] The recess 38 of the shift rail 34 may be defined by a pair of side walls 56 extending below the external surface 36 that are spaced from and facing one another and a bottom wall 58 extending between the pair of side walls 56. In the embodiments shown in Figures 3-7, 9A, and 9B, the pair of side walls 56 extend orthogonal to the rail axis Rl to abut the pin 44 and couple the shift fork 40 with the shift rail 34 as the shift rail 34 moves along the rail axis Rl. Said differently, the side walls 56 present an engagement surface to contact the pin 44 and move the shift fork 40 with the shift rail 34 along the rail axis Rl. However, one having skill in the art will appreciate that the side walls 56 may be arranged in non-orthogonal configurations and still facilitate movement of the shift fork 40 with the shift rail 34. As shown in the Figures, the side walls 56 are generally planar; however, the side walls 56 may curved, angular, or any other suitable configuration for abutting the pin 44.

[0051] As shown in Figures 4, 6, and 8, the first end 46 of the pin 44 may have a first width Fl and the pair of side walls 56 may be spaced from one another a second width SI substantially equal to the first width Fl for reducing free play between the pin 44 and the shift rail 34 as the shift rail 34 moves along the rail axis Rl. Said differently, the pin 44 may have limited spacing from the side walls 56 when disposed in the recess 38 to limit the length of movement of the shift rail 34 along the rail axis Rl before contact is made between the pin 44 and the side walls 56. However, on the other hand, the pin 44 may be spaced from the side walls 56 to create free play between the pin 44 and the shift rail 34 if free play is desired.

[0052] As shown in Figures 4, 6, 9A, and 9B, the bottom wall 58 may extend between first and second recess ends 60, 62 orthogonal to the side walls 56. The bottom wall 58 may transition into the external surface 36 at the first and second recess ends 60, 62 for moving the first end 46 of the pin 44 between the recess 38 in the first rotational position and the external surface 36 in the second rotational position. As such, the first end 46 of the pin 44 (biased by the biasing member 50) slides along the bottom wall 58. If the shift rail 34 is rotated from the first rotational position to the second rotational position, the first end 46 slides along bottom wall 58 to either first recess end 60 or the second recess end 62 and onto the external surface 36 of the shift rail 34. If the shift rail 34 is rotated from the second rotational position to the first rotational position, the first end 46 slides along external surface 36 and down the bottom wall 58 at either first recess end 60 or the second recess end 62 into the recess 38.

[0053] The first rotational position of the shift rail 34 corresponds to any rotational position of the shift rail 34 where the first end 46 of the pin 44 is disposed between the pair of side walls 56. Said differently, the first rotational position corresponds to any rotational position of the shift rail 34 where the first end 46 of the pin 44 is disposed along the bottom wall 58 between the first and second recess ends 60, 62. Likewise, second rotational position corresponds to any rotational position of the shift rail 34 where the first end 46 of the pin 44 engages the external surface 36 of the shift rail 34. As such, the first and second rotational positions of the shift rail 34 merely describe a rotational position that correspond to the coupled and decoupled configurations, respectively. Furthermore, referring to the first and second rotational positions of the shift rail 34 is applied individually to each of the plurality of shift forks 40. Said differently, the shift rail 34 may be in the first rotational position for one or more of the shift forks 40 that is in the coupled configuration and may be simultaneously in the second rotational position for one or more of the shift forks 40 that is in the decoupled configuration, as shown in Figures 3, 4, and 6-9B.

[0054] The bottom wall 58 may have a planar configuration between the first and second recess ends 60, 62, as shown in Figures 3-5B. Alternatively, the bottom wall 58 may have an arcuate configuration between the first and second recess ends 60, 62, as shown in Figures 6 and 7. The arcuate configuration between the first and second recess ends 60, 62 increases exponentially increases the bias exerted on the pin 44 by the biasing member 50 as the shift rail 34 is rotated from the first rotational position to the second rotational position which may provide what is commonly referred to as haptic feedback that may be detected by an operator or a computer system. The haptic feedback serves to clearly distinguish the first and second rotational positions. Furthermore, as shown in Figures 6 and 7, the arcuate configuration may shorten the length between first and second recess ends 60, 62 compared to the planar configuration so as to shorten the rotational positions the shift rail 34 that define the first rotational position and the coupled configuration. One having skill in the art will appreciate that the bottom wall 58 may have any suitable configuration for defining the recess 38 of the shift rail 34.

[0055] As shown in Figures 3 -7, the shift fork 40 may define a hole 64 transverse to the rail axis Rl and may open towards each of the shift rail 34 and the locking plate 52. The pin 44 may extend through and be movable within the hole 64. Said differently, the pin 44 may slide within the hole 64 toward and away from each of the shift rail 34 and the locking plate 52. The second end 48 of the pin 44 and the cavity 54 of the locking plate 52 may have opposing cross- sectional configurations such that the second end 48 of the pin 44 is movable into the cavity 54 and engages the locking plate 52 during movement of the shift rail 34 along the rail axis Rl. Said differently, the pin 44 may have limited spacing from the locking plate 52 within the cavity 54 to limit movement between the shift fork 40 and the locking plate 52. More specifically, the shift fork 40 may frictionally engage the shift rail 34 within the bore 42 such that the shift fork 40 may move with the shift rail 34 along the rail axis Rl, even in the decoupled configuration. As such, limiting the spacing between the pin 44 and the locking plate 52 within the cavity 54 limits undesired movement of the shift fork 40 with the shift rail 34 along the rail axis Rl. However, on the other hand, the pin 44 may be spaced from the locking plate 52 within the cavity 54 to create free play between the pin 44 and the shift rail 34 if free play is desired.

[0056] The pin 44 may be movable orthogonal to the rail axis Rl between the coupled and decoupled configurations, as shown in Figures 3-9B. As shown in Figures 3-7, the pin 44 may move linearly between the coupled and decoupled configurations. Each of the pin 44 and the shift fork 40 may have a bias surface 66, with the bias surfaces 66 spaced from and facing one another and with the biasing member 50 abutting and biasing the bias surfaces 66 away from one another. As such, the biasing member 50 pushes against each of the pin 44 and the shift fork 40, and biases the pin 44 linearly toward the rail axis Rl.

[0057] Alternatively, the pin 44 may move pivotally between the coupled and decoupled configurations, as shown in Figures 8-9B. The pin 44 may be pivotally coupled to the shift fork 40 away from the first end 46. The pin 44 is shown to pivot about an axis substantially parallel to the rail axis Rl ; however, the pin 44 may pivot about an axis in any position relative to the rail axis Rl that facilitates movement of the pin 44 between the coupled and decoupled configurations. When the shift rail 34 is in the first rotational position, the first end 46 of the pin 44 is pivoted down into the recess 38 in the coupled configuration. When the shift rail 34 is the second rotational position, the first end 46 of the pin 44 is pivoted by engagement with the external surface 36 of the shift rail 34 and slides along the external surface 36.

[0058] Each of the pin 44 and the locking plate 52 may have the bias surface 66, with the bias surfaces 66 spaced from and facing one another and with the biasing member 50 abutting and biasing the bias surfaces 66 away from one another. As shown in Figures 9A and 9B, the bias surface 66 of the pin 44 is at the second end 48, with the pin 44 pivotally coupled between the first and second ends 46, 48. One having skill in the art will appreciate that the bias surface 66 of the pin 44 may be anywhere on the pin 44 spaced from the pivot axis to facilitate rotation about the pivot axis.

[0059] The biasing member 50 may be further defined as a pair of biasing members 50 abutting and biasing opposing sides of the pin 44 to facilitate pivoting of the pin 44 in a first rotational direction and a second rotational direction opposite the first rotational direction while maintaining biasing of the first end 46 of the pin 44 toward the rail axis Rl. As such, the first end 46 of the pin 44 is biased into the recess 38 when the shift rail 34 is in the first rotational position.

[0060] As shown in Figures 8-9B, the cavity 54 may include a longitudinal region 68 extending along the rail axis Rl and a lateral region 70 extending from the longitudinal region 68 orthogonal to the rail axis Rl. The second end 48 of the pin 44 is disposed in the longitudinal region 68 of the cavity 54 and is spaced from the locking plate 52 along the rail axis Rl in the coupled configuration such that the shift fork 40 is coupled to and movable with the shift rail 34 along the rail axis Rl. The second end 48 of the pin 44 is disposed in the lateral region 70 of the cavity 54 and engages the locking plate 52 along the rail axis Rl in the decoupled configuration such that the shift fork 40 is decoupled from the shift rail 34 and retained by the locking plate 52 to facilitate movement of the shift rail 34 independent of the shift fork 40 along the rail axis Rl. Furthermore, the longitudinal region 68 of the cavity 54 may have a length LI along the rail axis Rl, with the length LI being sufficient to facilitate desired movement of the shift fork 40 with the shift rail 34 along the rail axis Rl in the coupled configuration. [0061] Accordingly, the lateral region 70 of the cavity 54 allows movement of the pin 44 therein as the shift rail 34 rotates between the first and second rotational positions. Movement of the shift rail 34 along the rail axis Rl when the pin 44 is in the lateral region 70 (i.e., the decoupled configuration with the shift rail 34 in the second rotational position) causes the pin 44 to engage the locking plate 52 retains the shift fork 40 along the rail axis Rl.

[0062] Furthermore, the longitudinal region 68 of the cavity 54 allows movement of the pin 44 therein as the shift rail 34 moves along the rail axis Rl (with the pin 44 in the coupled configuration and the shift rail 34 in the first rotational position). The longitudinal region 68 is sufficient to facilitate desired movement of the shift fork 40 along the rail axis Rl in the coupled configuration. Desired movement of the shift rail 34 may be moving the shift fork 40 and corresponding ring 30 to shift between transmission "speeds". Rotation of the shift rail 34 toward the second rotational position causes the pin 44 to engage the locking plate 52, which prevents further undesired rotation to the second rotational position and the decoupled configuration.

[0063] As shown in Figure 8, the longitudinal and lateral regions 68, 70 may cross one another to form a generally "T" shaped configuration. As such, in the coupled configuration, the shift fork 40 may move according to the longitudinal region 68 fore and aft of the lateral region 70 (i.e., the region for coupling and decoupling the shift fork 40), which increases the range of movement of the corresponding ring 30 to shift between transmission "speeds". The extension of the lateral region 70 to the left and right of the longitudinal region 68 allows for transition to the decoupling configuration in both the left and right portions of the lateral region 70. As such, the shift rail 34 may be rotated to two separate second rotational positions (i.e., one in the left portion of the lateral region 70 and one in the right portion of the lateral region 70) for transitioning the pin 44 to the decoupled configuration.

[0064] The present invention also provides an embodiment of the shift fork lock system 72 that includes a shift rail 74 extending along a rail axis R2 as shown in Figures 10-12. The shift rail 74 is movable axially along and rotatably around the rail axis R2. The shift rail 74 has a protrusion 76 extending radially from the rail axis R2 to an engagement surface 78.

[0065] The shift fork lock system 72 further includes the shift fork 80 defining a bore 82 along the axis. The shift rail 74 extends through the bore 82 and is movable axially and rotatably relative to the shift fork 80 when the shift fork 80 is in a decoupled configuration. The shift fork 80 has an external surface 84 and defines first and second voids 86, 88 extending below the external surface 84. The first and second voids 86, 88 open to one another such that the protrusion 76 is disposed within and movable between the first and second voids 86, 88.

[0066] As shown in Figure 10, the shift fork lock system 72 further includes a locking plate 90 extending along the rail axis R2 and defining a cavity 92 and a pin 94 coupled to and movable relative to the locking plate 90 within the cavity 92. The pin 94 has first and second ends 96, 98. The first end 96 engages at least one of the protrusion 76 of the shift rail 74 and the external surface 84 of the shift fork 80 in a coupled configuration and is disposed within the first void 86 of the shift fork 80 in a decoupled configuration.

[0067] The shift fork lock system 72 further includes a biasing member 100 abutting the second end 98 of the pin 94 and biasing the pin 94 toward the rail axis R2. The shift rail 74 is rotatable to a first rotational position to dispose the protrusion 76 in the first void 86 and in engagement with the shift fork 80 in the coupled configuration. The engagement surface 78 of the protrusion 76 moves the pin 94 away from the rail axis R2 against the bias of the biasing member 100 to slidably dispose the first end 96 of the pin 94 along the external surface 84 and the engagement surface 78 such that the shift fork 80 is coupled to and movable with the shift rail 74 along the rail axis R2. The shift rail 74 is rotatable to a second rotational position to dispose the protrusion 76 in the second void 88 in the decoupled configuration. The first end 96 of the pin 94 is disposed in the first void 86 and is in engagement with the shift fork 80. The protrusion 76 is movable within the second void 88 along the rail axis R2 such that the shift fork 80 is decoupled from the shift rail 74 and is retained by the locking plate 90 to facilitate movement of the shift rail 74 independent of the shift fork 80 along the rail axis R2.

[0068] Said differently, when the shift rail 74 is moved to the first rotational position, the shift fork 80 is coupled to and moves with shift rail 74 along the rail axis R2. When the shift rail 74 is moved to the second rotational position, the shift fork 80 is coupled to the locking plate 90 and remains stationary with the locking plate 90 as the shift rail 74 moves along the rail axis R2. Accordingly, rotation of the shift rail 74 between the first and second rotational positions allow for selective engagement and axial movement of the shift fork 80 to shift between transmission "speeds".

[0069] As shown in Figure 10, the protrusion 76, the shift fork 80, the pin 94, the biasing member 100, and the cavity 92 may be further defined as a plurality of the protrusions 76, a plurality of shift forks 80, a plurality of pins 94, a plurality of biasing members 100, and a plurality of cavities 92 individually corresponding to one another. Each of the shift forks 80 are configured to alternate between coupled and decoupled configurations. More specifically, as shown in Figure 1 , the plurality of shift forks 80 may each individually engage a respective ring 30. As shown in Figure 10, the plurality of shift forks 80 may each be alternated between the coupled and decoupled configurations independent of one another. As such, one or more of the shift forks 80 may be in the coupled configuration for a given rotation of the shift rail 74 and one or more of the shift forks 80 may be in the decoupled configuration for a given rotation of the shift rail 74. Therefore, depending on the rotation of the shift rail 74 certain shift fork(s) 80 may move axially with shift rail 74 to move the respective ring(s) 30 of the transmission while certain shift fork(s) 80 may be retained by the locking member to prevent movement of the respective ring(s) 30 of the transmission. The description below describes one shift fork 80 and the mechanisms through which shift fork 80 alternates between the coupled and decoupled configurations. One having skill in the art will appreciate that the description may be applicable to each of the plurality of shift forks 80.

[0070] In the embodiment shown in Figure 10, the locking plate 90 is fixed along the rail axis R2. However, one having skill in the art will appreciate may be configured to move along the rail axis R2 (either with the shift rail 74 or independent of the shift rail 74).

[0071] The first void 86 of the shift fork 80 may be defined by a pair of side walls 102 extending below the external surface 84 that are spaced from and facing one another. In the embodiments shown in Figures 10-12, the pair of side walls 102 extend orthogonal to the rail axis R2 to abut the protrusion 76 in the first rotational position and the first end 96 of the pin 94 in the second rotational position. Said differently, the side walls 102 present an engagement surface to contact the protrusion 76 and move the shift fork 80 with the shift rail 74 along the rail axis R2 in the first rotational position or the first end 96 of the pin 94 and retain the shift fork 80 with the locking plate 90 in the second rotational position. However, one having skill in the art will appreciate that the side walls 102 may be arranged in non-orthogonal configurations and still facilitate movement of the shift fork 80 with the shift rail 74 in the first rotational position and retention of the shift fork 80 with the locking plate 90 in the second rotational position. As shown in the Figures, the side walls 102 are generally planar; however, the side walls 102 may curved, angular, or any other suitable configuration for abutting the protrusion 76 and the pin 94.

[0072] As shown in Figure 10, the protrusion 76 may have a first width F2 and the pair of side walls 102 may be spaced from one another a second width S2 substantially equal to the first width F2 for reducing free play between the shift fork 80 and the shift rail 74 as the shift fork 80 moves with the shift rail 74 along the rail axis R2. Said differently, the protrusion 76 may have limited spacing from the side walls 102 when disposed in the first void 86 to limit the length of movement of the shift rail 74 along the rail axis R2 before contact is made between the protrusion 76 and the side walls 102. However, on the other hand, the protrusion 76 may be spaced from the side walls 102 to create free play between the shift fork 80 and the shift rail 74 if free play is desired.

[0073] As shown in Figure 10, the first end 96 of the pin 94 may have a third width T2 substantially equal to the second width S2 between the pair of side walls 102 for reducing free play between the shift fork 80 and the locking plate 90 as the shift rail 74 moves independent of the shift fork 80 along the rail axis R2. Said differently, the pin 94 may have limited spacing from the side walls 102 when disposed in the first void 86 to limit the between the shift fork 80 and the locking plate 90. More specifically, the shift fork 80 may frictionally engage the shift rail 74 within the bore 82 such that the shift fork 80 may move with the shift rail 74 along the rail axis R2, even in the decoupled configuration. As such, limiting the spacing between the pin 94 and the side walls 102 limits undesired movement of the shift fork 80 with the shift rail 74 along the rail axis R2. However, on the other hand, the pin 94 may be spaced from the side walls 102 to create free play between the pin 94 and the shift rail 74 if free play is desired. [0074] The first rotational position of the shift rail 74 corresponds to any rotational position of the shift rail 74 where the protrusion 76 is disposed between the pair of side walls 102. Likewise, the second rotational position corresponds to any rotational position of the shift rail 74 where the first end 96 of the pin 94 is disposed between the pair of side walls 102. As such, the first and second rotational positions of the shift rail 74 merely describe a rotational position that correspond to the coupled and decoupled configurations, respectively. Furthermore, referring to the first and second rotational positions of the shift rail 74 is applied individually to each of the plurality of shift forks 80. Said differently, the shift rail 74 may be in the first rotational position for one or more of the shift forks 80 that is in the coupled configuration and may be simultaneously in the second rotational position for one or more of the shift forks 80 that is in the decoupled configuration, as shown in Figure 10.

[0075] As shown in Figure 11, the second void 88 may have a length L2 along the rail axis R2. The length L2 is sufficient to facilitate desired movement of the shift rail 74 independent of the shift fork 80 along the rail axis R2 in the decoupled configuration. Desired movement of the shift rail 74 may be moving another shift fork 80 and corresponding ring 30 to shift between transmission "speeds".

[0076] The second void 88 may be further defined as a pair of second voids 86, 88 on opposing sides of the first void 86. The first void 86 opens into each of the pair of second voids 86, 88 such that the protrusion 76 is disposed within and movable between the first void 86 and each of the pair of the second voids 86, 88. The protrusion 76 is disposed in either of the pair of second voids 86, 88 in the second rotational position of the shift rail 74. Said differently, the shift rail 74 may be rotated to two separate second rotational positions (i.e., the protrusion 76 disposed in either of the pair of second voids 86, 88) for transitioning the shift fork 80 to the decoupled configuration.

[0077] As shown in Figure 10, the pin 94 and the cavity 92 of the locking plate 90 may have opposing cross-sectional configurations such that the pin 94 is movable within the cavity 92 and engages the locking plate 90 during movement of the shift rail 74 along the rail axis R2 independent of the shift fork 80 when the first end 96 of the pin 94 is disposed within the first void 86 of the shift fork 80. Said differently, the pin 94 may have limited spacing from the locking plate 90 within the cavity 92 to limit movement between the shift fork 80 and the locking plate 90. More specifically, the shift fork 80 may frictionally engage the shift rail 74 within the bore 82 such that the shift fork 80 may move with the shift rail 74 along the rail axis R2, even in the decoupled configuration. As such, limiting the spacing between the pin 94 and the locking plate 90 within the cavity 92 limits undesired movement of the shift fork 80 with the shift rail 74 along the rail axis R2. However, on the other hand, the pin 94 may be spaced from the locking plate 90 within the cavity 92 to create free play between the pin 94 and the shift rail 74 if free play is desired.

[0078] The pin 94 may be movable within the cavity 92 of the locking plate 90 orthogonal to the rail axis R2, as shown in Figure 10. Furthermore, the pin 94 may move linearly within the cavity 92 of the locking plate 90. The biasing member 100 may abut and bias each of the pin 94 and the locking plate 90. As such, the biasing member 100 pushes against each of the pin 94 and the locking plate 90, and biases the pin 94 linearly toward the rail axis R2. One having skill in the art will appreciate that the biasing member 100 may abut the pin 94 and any other fixed component to bias the pin 94 linearly toward the rail axis R2. [0079] The present invention also provides an embodiment of the shift fork lock system 104 that includes a shift rail 106 extending along a rail axis R3, as shown in Figures 13- 16. The shift rail 106 is movable axially along and rotatably around the rail axis R3. The shift rail 106 has an external surface 108 and defines a groove 110 extending below the external surface 108 and having first and second regions 112, 114, as shown in Figure 16. The second region 114 extends further below the external surface 108 than the first region 112.

[0080] As shown in Figure 13 and 16, the shift fork lock system 104 further includes the shift fork 116 having an internal surface 118 defining a bore 120 along the rail axis R3. The shift rail 106 extends through the bore 120 and is movable axially and rotatably relative to the shift fork 116 when the shift fork 116 is in a decoupled configuration. The shift fork 116 defines a detent 122 extending below the internal surface 118 away from the shift rail 106.

[0081] The shift fork lock system 104 further includes a ball 124 coupled to and movable relative to the shift rail 106. The ball 124 is disposed in the first region 112 of the groove 110 in a coupled configuration and in the second region 114 of the groove 110 in the decoupled configuration.

[0082] The shift rail 106 is rotatable to a first rotational position with the ball 124 disposed in both the detent 122 and the first region 112 of the groove 110 in the coupled configuration such that the shift fork 116 is coupled to and movable with the shift rail 106 along the rail axis R3. The shift rail 106 is rotatable to a second rotational position with the ball 124 disposed in the second region 114 of the groove 110 and Tollable along the internal surface 118 of the shift fork 116 in the decoupled configuration such that the shift fork 116 is decoupled from the shift rail 106 to facilitate movement of the shift rail 106 independent of the shift fork 116 along the rail axis R3. Said differently, when the shift rail 106 is moved to the first rotational position, the shift fork 116 is coupled to and moves with shift rail 106 along the rail axis R3. Accordingly, rotation of the shift rail 106 between the first and second rotational positions allow for selective engagement and axial movement of the shift fork 116 to shift between transmission "speeds".

[0083] As shown in Figures 13 and 14, the shift fork 116, the ball 124, and the groove 110 may be further defined as a plurality of shift forks 116, a plurality of balls 124, and a plurality of grooves 110 individually corresponding to one another, with each of the shift forks 116 configured to alternate between coupled and decoupled configurations. More specifically, as shown in Figure 1 , the plurality of shift forks 116 may each individually engage a respective ring 30. As shown in Figure 13, the plurality of shift forks 116 may each be alternated between the coupled and decoupled configurations independent of one another. As such, one or more of the shift forks 116 may be in the coupled configuration for a given rotation of the shift rail 106 and one or more of the shift forks 116 may be in the decoupled configuration for a given rotation of the shift rail 106. Therefore, depending on the rotation of the shift rail 106 certain shift fork(s) 116 may move axially with shift rail 106 to move the respective ring(s) 30 of the transmission while certain shift fork(s) 116 may not move with the shift rail 106 to prevent movement of the respective ring(s) 30 of the transmission. The description below describes one shift fork 116 and the mechanisms through which shift fork 116 alternates between the coupled and decoupled configurations. One having skill in the art will appreciate that the description may be applicable to each of the plurality of shift forks 116.

[0084] As shown in Figures 13-16, the groove 110 of the shift rail 106 may be defined by a pair of side walls 126 extending below the external surface 108 that are spaced from and facing one another and a bottom wall 128 extending between the pair of side walls 126. In the embodiment shown in Figures 13-16, the pair of side walls 126 extend orthogonal to the rail axis R3 to abut the ball 124 and couple the ball 124 to the shift rail 106 along the rail axis R3. Said differently, the side walls 126 present an engagement surface to contact the ball 124 and move the ball 124 with the shift rail 106 along the rail axis R3. However, one having skill in the art will appreciate that the side walls 126 may be arranged in non-orthogonal configurations and still facilitate movement of the ball 124 with the shift rail 106. As shown in the Figures, the side walls 126 are generally planar; however, the side walls 126 may curved, angular, or any other suitable configuration for abutting the ball 124.

[0085] As shown in Figure 13, the ball 124 may have a first width F3 and the pair of side walls 126 may be spaced from one another a second width S3 substantially equal to the first width F3 for reducing free play between the ball 124 and the shift rail 106 as the shift rail 106 moves along the rail axis R3. Said differently, the ball 124 may have limited spacing from the side walls 126 when disposed in the groove 110 to limit the length of movement of the shift rail 106 along the rail axis R3 before contact is made between the ball 124 and the side walls 126. However, on the other hand, the ball 124 may be spaced from the sidewalls to create free play between the ball 124 and the shift rail 106 if free play is desired.

[0086] As shown in Figures 13 and 16, the detent 122 of the shift fork 116 may be defined by a detent wall 130 configured to surround the ball 124. The ball 124 abuts each of the side walls 126 and the detent wall 130 in the coupled configuration when the shift rail 106 is in the first rotational position to couple the shift fork 116 with the shift rail 106 as the shift rail 106 moves along the rail axis R3. In the embodiment shown in Figures 13 and 16, the detent wall 130 of the shift fork 116 has a conical configuration that transitions to the internal surface 118 of the shift fork 116 for movement of the ball 124 to the internal surface 118 in the second rotational positon of the shift rail 106 and the detent 122 in the first rotational position. As such, if the shift rail 106 is rotated from the first rotational position to the second rotational position, the ball 124 rolls along the detent wall 130 and onto the internal surface 118 of the shift fork 116 and disposed in the second region 114 of the groove 110. The ball 124 rolls along the internal surface 118 of the shift fork 116 within the second region 114 of the groove 110 as the shift rail 106 moves along the rail axis R3, independent of the shift fork 116. If the shift rail 106 is rotated from the second rotational position to the first rotational position, the ball 124 rolls along the internal surface 118 of the shift fork 116 and down the detent wall 130 into the detent 122. Furthermore, the bottom wall 128 may extend toward the external surface 108 of the shift rail 106 in the first region 112 of the groove 110 to define a ridge 132 (as shown in Figure 16), with the ball 124 sitting on the ridge 132 and disposed within the first region 112 of the groove 110 in the coupled configuration. The ridge 132 positions and retains the ball 124 in the detent 122. With the ball 124 retained in the detent 122, the ball 124 engages each of the detent wall 130 of the shift fork 116 and the side walls 126 of the shift rail 106 to couple the shift fork 116 to the shift rail 106 as the shift rail 106 moves along the rail axis R3.

[0087] The first rotational position of the shift rail 106 corresponds to any rotational position of the shift rail 106 where the ball 124 is disposed in the detent 122 and between the pair of side walls 126 of the groove 110. Likewise, second rotational position corresponds to any rotational position of the shift rail 106 where the ball 124 engages the internal surface 118 of the shift fork 116. As such, the first and second rotational positions of the shift rail 106 merely describe a rotational position that correspond to the coupled and decoupled configurations, respectively. Furthermore, referring to the first and second rotational positions of the shift rail 106 is applied individually to each of the plurality of shift forks 116. Said differently, the shift rail 106 may be in the first rotational position for one or more of the shift forks 116 that is in the coupled configuration and may be simultaneously in the second rotational position for one or more of the shift forks 116 that is in the decoupled configuration, as shown in Figure 13.

[0088] As shown in Figure 16, the second region 114 of the groove 110 may be further defined as a pair of second regions 114 on opposing sides of the first region 112. The first region 112 opens into each of the pair of second regions 114 such that the ball 124 is disposed within and movable between the first region 112 and each of the pair of the second regions 114. The ball 124 is disposed in either of the pair of second regions 114 in the second rotational position of the shift rail 106. Said differently, the shift rail 106 may be rotated to two separate second rotational positions (i.e., the ball 124 disposed in either of the pair of second regions 114) for transitioning the shift fork 116 to the decoupled configuration.

[0089] As shown in Figure 13, the shift fork lock system 104 may further include a locking plate 134 extending along the rail axis R3 and defining a hole 136. Furthermore, the shift fork lock system 104 may further include a slide rail 138 extending along the rail axis R3 parallel to the shift rail 106. The slide rail 138 is adjacent the locking plate 134, with the locking plate 134 disposed between the slide rail 138 and the shift rail 106. The slide rail 138 is pivotally coupled to the shift rail 106. The slide rail 138 moves with the shift rail 106 along the rail axis R3. The shift rail 106 rotates independent of the slide rail 138 about the rail axis R3 between the first and second rotational positions.

[0090] The shift fork 116 defines a second detent 140 extending away from the locking plate 134. The second detent 140 corresponds to the hole 136 of the locking plate 134. The slide rail 138 defines a cavity 142 opening toward and corresponding with the hole 136 of the locking plate 134. [0091] The shift fork lock system 104 further includes a second ball 144. The second ball 144 is disposed in at least one of the hole 136, the second detent 140, and the cavity 142. When the shift rail 106 is in the second rotational position, the second ball 144 is disposed in the second detent 140 of the shift fork 116 and the hole 136 of the locking plate 134. The second ball 144 engages each of the shift fork 116 and the locking plate 134 as the shift rail 106 moves along the rail axis R3. The locking plate 134 retains the shift fork 116 and facilitates movement of the shift rail 106 independent of the shift fork 116 along the rail axis R3.

[0092] When the shift rail 106 moves from the second rotational position to the first rotational position, the second ball 144 moves entirely into the cavity 142 of the slide rail 138. The locking plate 134 may have a taper in the hole 136 to facilitate movement of the second ball 144 up the taper into the cavity 142. Alternatively, the second ball 144 may have a diameter greater than a diameter of the hole 136, which facilitates the second ball 144 rolling up the locking plate 134 through the hole 136 into the cavity 142. With the second ball 144 disposed in the cavity 142, the second ball 144 may roll along the locking plate 134 as the shift rail 106 moves along the rail axis R3. The shift fork 116 is disconnected from the locking plate 134 and is coupled to the shift rail 106 in the coupled configuration as described in detail above.

[0093] As shown in Figure 13, the shift fork 116, the second ball 144, and the hole 136, and the cavity 142 may be further defined as a plurality of shift forks 116, a plurality of second balls 144, a plurality of holes 136, and a plurality of cavities 142 individually corresponding to one another, with each of the shift forks 116 configured to alternate between coupling and decoupling with the locking plate 134.

[0094] The invention has been described in an illustrative manner, and it is to be understood that the terminology that has been used is intended to be in the nature of words of description rather than of limitation. As is now apparent to those skilled in the art, many modifications and variations of the subject invention are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims, wherein reference numerals are merely for convenience and are not to be in any way limiting, the invention may be practiced otherwise than as specifically described.

Claims

CLAIMS What is claimed is:

1. A shift fork lock system for a transmission, said shift fork lock system comprising:

a shift rail extending along a rail axis, with said shift rail movable axially along and rotatably around said rail axis, and with said shift rail having an external surface and defining a recess extending below said external surface;

a shift fork defining a bore along said rail axis, with said shift rail extending through said bore and with said shift rail movable axially and rotatably relative to said shift fork when said shift fork is in a decoupled configuration;

a pin coupled to and movable relative to said shift fork, with said pin having first and second ends, and with said first end engaging said external surface of said shift rail in said decoupled configuration and disposed in said recess in a coupled configuration;

a biasing member abutting and biasing said first end of said pin toward said rail axis; and a locking plate extending along said rail axis and defining a cavity configured to receive said second end of said pin;

wherein said shift rail is rotatable to a first rotational position with said first end of said pin disposed in said recess of said shift rail in said coupled configuration and said second end of said pin spaced from said locking plate such that said shift fork is coupled to and movable with said shift rail along said rail axis; and

wherein said shift rail is rotatable to a second rotational position with said first end of said pin engaged with and slidable along said external surface of said shift rail in said decoupled configuration and said second end of said pin disposed in said cavity of said locking plate such that said shift fork is decoupled from said shift rail and retained by said locking plate to facilitate movement of said shift rail independent of said shift fork along said rail axis.

2. The shift fork lock system as set forth in claim 1, wherein said recess of said shift rail is defined by a pair of side walls extending below said external surface that are spaced from and facing one another and a bottom wall extending between said pair of side walls.

3. The shift fork lock system as set forth in claim 2, wherein said pair of side walls extend orthogonal to said rail axis to abut said pin and couple said shift fork with said shift rail as said shift rail moves along said rail axis.

4. The shift fork lock system as set forth in claim 3, wherein said first end of said pin has a first width and said pair of side walls are spaced from one another a second width substantially equal to said first width for reducing free play between said pin and said shift rail as said shift rail moves along said rail axis.

5. The shift fork lock system as set forth in claim 3, wherein said bottom wall extends between first and second recess ends orthogonal to said side walls, with said bottom wall transitioning into said external surface at said first and second recess ends for moving said first end of said pin between said recess in said first rotational position and said external surface in said second rotational position.

6. The shift fork lock system as set forth in claim 5, wherein said bottom wall has a planar configuration between said first and second recess ends.

7. The shift fork lock system as set forth in claim 5, wherein said bottom wall has an arcuate configuration between said first and second recess ends.

8. The shift fork lock system as set forth in claim 1, wherein said shift fork defines a hole transverse to said rail axis and opening towards each of the shift rail and the locking plate, with said pin extending through and movable within said hole.

9. The shift fork lock system as set forth in claim 1, wherein said second end of said pin and said cavity of said locking plate have opposing cross-sectional configurations such that said second end of said pin is movable into said cavity and engages said locking plate during movement of said shift rail along said rail axis.

10. The shift fork lock system as set forth in claim 1, wherein said pin is movable orthogonal to said rail axis between said coupled and decoupled configurations.

11. The shift fork lock system as set forth in claim 10, wherein said pin moves linearly between said coupled and decoupled configurations.

12. The shift fork lock system as set forth in claim 11, wherein each of said pin and said shift fork has a bias surface, with said bias surfaces spaced from and facing one another and with said biasing member abutting and biasing said bias surfaces away from one another.

13. The shift fork lock system as set forth in claim 10, wherein said pin moves pivotally between said coupled and decoupled configurations.

14. The shift fork lock system as set forth in claim 13, wherein each of said pin and said locking plate has a bias surface, with said bias surfaces spaced from and facing one another and with said biasing member abutting and biasing said bias surfaces away from one another.

15. The shift fork lock system as set forth in claim 13, wherein said biasing member is further defined as a pair of biasing members abutting and biasing opposing sides of said pin to facilitate pivoting of said pin in a first rotational direction and a second rotational direction opposite said first rotational direction while maintaining biasing of said first end of said pin toward said rail axis.

16. The shift fork lock system as set forth in claim 13, wherein said cavity includes a longitudinal region extending along the rail axis and a lateral region extending from the longitudinal region orthogonal to the rail axis, with said second end of said pin disposed in said longitudinal region of said cavity and spaced from said locking plate along said rail axis in said coupled configuration such that said shift fork is coupled to and movable with said shift rail along said rail axis, and with said second end of said pin disposed in said lateral region of said cavity and engaging said locking plate along said rail axis such that said shift fork is decoupled from said shift rail and retained by said locking plate to facilitate movement of said shift rail independent of said shift fork along said rail axis.

17. The shift fork lock system as set forth in claim 16, wherein said longitudinal region of said cavity has a length along said rail axis, with said length being sufficient to facilitate desired movement of said shift fork with said shift rail along said rail axis in said coupled configuration.

18. The shift fork lock system as set forth in claim 1, wherein said locking plate is fixed along said rail axis.

19. The shift fork lock system as set forth in claim 1, wherein said shift fork, said pin, said biasing member, said recess, and said cavity are further defined as a plurality of shift forks, a plurality of pins, a plurality of biasing members, a plurality of recesses, and a plurality of cavities individually corresponding to one another, with each of said shift forks configured to alternate between coupled and decoupled configurations.

20. A shift fork lock system for a transmission, said shift fork lock system comprising:

a shift rail extending along a rail axis, with said shift rail movable axially along and rotatably around said rail axis, and with said shift rail having a protrusion extending radially from said rail axis to an engagement surface;

a shift fork defining a bore along said axis, with said shift rail extending through said bore and said shift rail movable axially and rotatably relative to said shift fork when said shift fork is in a decoupled configuration, with said shift fork having an external surface and defining first and second voids extending below said external surface, and with said first and second voids open to one another such that said protrusion is disposed within and movable between said first and second voids;

a locking plate extending along said rail axis and defining a cavity;

a pin coupled to and movable relative to said locking plate within said cavity, with said pin having first and second ends, and with said first end engaging at least one of said protrusion of said shift rail and said external surface of said shift fork in a coupled configuration and disposed within said first void of said shift fork in a decoupled configuration; and

a biasing member abutting said second end of said pin and biasing said pin toward said rail axis;

wherein said shift rail is rotatable to a first rotational position to dispose said protrusion in said first void and in engagement with said shift fork in said coupled configuration, with said engagement surface of said protrusion moving said pin away from said rail axis against said bias of said biasing member to slidably dispose said first end of said pin along said external surface and said engagement surface such that said shift fork is coupled to and movable with said shift rail along said rail axis; and

wherein said shift rail is rotatable to a second rotational position to dispose said protrusion in said second void in said decoupled configuration, with said first end of said pin disposed in said first void and in engagement with said shift fork and said protrusion movable within said second void along said rail axis such that said shift fork is decoupled from said shift rail and retained by said locking plate to facilitate movement of said shift rail independent of said shift fork along said rail axis.

21. The shift fork lock system as set forth in claim 19, wherein said first void of said shift fork is defined by a pair of side walls extending below said external surface that are spaced from and facing one another.

22. The shift fork lock system as set forth in claim 20, wherein said pair of side walls extend orthogonal to said rail axis to abut said protrusion in said first rotational position and said first end of said pin in said second rotational position.

23. The shift fork lock system as set forth in claim 22, wherein said protrusion has a first width and said pair of side walls are spaced from one another a second width substantially equal to said first width for reducing free play between said shift fork and said shift rail as said shift fork moves with said shift rail along said rail axis.

24. The shift fork lock system as set forth in claim 22, wherein said first end of said pin has a third width substantially equal to said second width between said pair of side walls for reducing free play between said shift fork and said locking plate as said shift rail moves independent of said shift fork along said rail axis.

25. The shift fork lock system as set forth in claim 20, wherein said second void has a length along said rail axis, with said length being sufficient to facilitate desired movement of said shift rail independent of said shift fork along said rail axis in said decoupled configuration.

26. The shift fork lock system as set forth in claim 20, wherein said second void is further defined as a pair of second voids on opposing sides of said first void, with said first void opening into each of said pair of second voids such that said protrusion is disposed within and movable between said first void and each of said pair of said second voids, and with said protrusion disposed in either of said pair of second voids in said second rotational position of said shift rail.

27. The shift fork lock system as set forth in claim 20, wherein said pin and said cavity of said locking plate have opposing cross-sectional configurations such that said pin is movable within said cavity and engages said locking plate during movement of said shift rail along said rail axis independent of said shift fork when said first end of said pin is disposed within said first void of said shift fork.

28. The shift fork lock system as set forth in claim 20, wherein said pin is movable within said cavity of said locking plate orthogonal to said rail axis.

29. The shift fork lock system as set forth in claim 28, wherein said pin moves linearly within said cavity of said locking plate.

30. The shift fork lock system as set forth in claim 20, wherein said locking plate is fixed along said rail axis.

31. The shift fork lock system as set forth in claim 20, wherein said protrusion, said shift fork, said pin, said biasing member, and said cavity are further defined as a plurality of said protrusions, a plurality of shift forks, a plurality of pins, a plurality of biasing members, and a plurality of cavities individually corresponding to one another, with each of said shift forks configured to alternate between coupled and decoupled configurations.

32. A shift fork lock system for a transmission, said shift fork lock system comprising:

a shift rail extending along a rail axis, with said shift rail movable axially along and rotatably around said rail axis, said with shift rail having an external surface and defining a groove extending below said external surface and having first and second regions, with said second region extending further below said external surface than said first region;

a shift fork having an internal surface defining a bore along said rail axis, with said shift rail extending through said bore and said shift rail movable axially and rotatable relative to said shift fork when said shift fork is in a decoupled configuration, and with said shift fork defining a detent extending below said internal surface away from said shift rail; and

a ball coupled to and movable relative to said shift rail, with said ball disposed in said first region of said groove in a coupled configuration and in said second region of said groove in said decoupled configuration;

wherein said shift rail is rotatable to a first rotational position with said ball disposed in both said detent and said first region of said groove in said coupled configuration such that said shift fork is coupled to and movable with said shift rail along said rail axis; and

wherein said shift rail is rotatable to a second rotational position with said ball disposed in said second region of said groove and Tollable along said internal surface of said shift fork in said decoupled configuration such that said shift fork is decoupled from said shift rail to facilitate movement of said shift rail independent of said shift fork along said rail axis.

33. The shift fork lock system as set forth in claim 32, wherein said groove of said shift rail is defined by a pair of side walls extending below said external surface that are spaced from and facing one another and a bottom wall extending between said pair of side walls.

34. The shift fork lock system as set forth in claim 33, wherein said pair of side walls extend orthogonal to said rail axis to abut said ball and couple said ball to said shift rail along said rail axis.

35. The shift fork lock system as set forth in claim 34, wherein said detent of said shift fork is defined by a detent wall configured to surround said ball, with said ball abutting each of said side walls and said detent wall in said coupled configuration when said shift rail is in said first rotational position to couple said shift fork with said shift rail as said shift rail moves along said rail axis.

36. The shift fork lock system as set forth in claim 34, wherein said detent wall of said shift fork has a conical configuration that transitions to said internal surface of said shift fork for movement of said ball to said internal surface in said second rotational positon of said shift rail and said detent in said first rotational position.

37. The shift fork lock system as set forth in claim 32, wherein said bottom wall extends toward said external surface of said shift rail in said first region of said groove to define a ridge, with said ball sitting on said ridge and disposed within said first region of said groove in said coupled configuration.

38. The shift fork lock system as set forth in claim 32, wherein said second region of said groove is further defined as a pair of second regions on opposing sides of said first region, with said first region opening into each of said pair of second regions such that said ball is disposed within and movable between said first region and each of said pair of said second regions, and with said ball disposed in either of said pair of second regions in said second rotational position of said shift rail.