Dual clutch multi-speed transmission

A transmission includes an input member, an output transfer gear, first and second shaft members, first and second counter shaft members, a plurality of co-planar gear sets, and a plurality of torque transmitting devices. The torque transmitting devices include a plurality of synchronizer assemblies and a dual clutch assembly. The transmission is operable to provide at least one reverse speed ratio and a plurality of forward speed ratios between the input member and the output member.

TECHNICAL FIELD

The present disclosure relates to transmissions and more particularly to a compact, dual clutch multiple speed transmission having three axes to establish five or more gear speeds.

BACKGROUND

A typical multiple speed transmission having countershafts and co-planar gear sets uses countershaft gears with a different, dedicated gear pair or set to achieve each forward speed ratio. Accordingly, the total number of gears required in this typical design is two times the number of forward speeds, plus three for reverse. This necessitates a large number of required gear pairs, especially in transmissions that have a relatively large number of forward speed ratios.

While current transmissions achieve their intended purpose, the need for new and improved transmission configurations which exhibit improved performance, especially from the standpoints of efficiency, responsiveness and smoothness and improved packaging, primarily reduced size and weight, is essentially constant. Accordingly, there is a need in the art for a transmission having improved packaging while providing desirable gear ratios and torque ranges.

SUMMARY

The present invention provides a transmission having an input member, an output member, first and second shaft members, first and second countershaft members, a plurality of co-planar gear sets, and a plurality of torque transmitting devices. The torque transmitting devices include a plurality of synchronizer assemblies and a dual clutch assembly. The transmission is operable to provide at least one reverse speed ratio and a plurality of forward speed ratios between the input member and the output member.

In one aspect of the present invention, the transmission includes five co-planar gear sets.

In yet another aspect of the present invention, the transmission includes four synchronizer assemblies.

In yet another aspect of the present invention, the four synchronizer assemblies include two one-way synchronizers and two two-way synchronizers.

In yet another aspect of the present invention, the transmission is operable to provide at least five forward speed ratios.

In yet another aspect of the present invention, a dual clutch transmission is provided having a transmission housing, five gear sets, a first and second transmission input members, a first and second countershafts, a dual clutch assembly and four synchronizer assemblies.

In still another aspect of the present invention, the first gear set has a first gear in mesh with a second gear. The second gear set has a first gear in mesh with a second gear. The third gear set has a first gear in mesh with a second gear. The fourth gear set has a first gear in mesh with a second gear. The fifth gear set has a first gear in mesh with a second gear and a third gear in mesh with the second gear.

In still another aspect of the present invention, the first transmission input member is rotatably supported in the transmission housing. Each of the first gear of the third, fourth and fifth gear sets are rotatably fixed for common rotation with the first transmission input member.

In still another aspect of the present invention, the second transmission input member is rotatably supported in the transmission housing. Each of the first gear of the first and second gear sets are rotatably fixed for common rotation with the second transmission input member. The second transmission input member is concentric with the first transmission input member and at least partially surrounds the first transmission input member.

In still another aspect of the present invention, the first countershaft is rotatably supported within the transmission housing and spaced apart from and parallel with the first and second transmission input members. The second gear of the second gear set, the second gear of the third gear set and the second gear of the fifth gear set are each selectively connectable for common rotation with the first countershaft.

In still another aspect of the present invention, the second countershaft is rotatably supported within the transmission housing and spaced apart from and parallel with the first and second transmission input members. The second gear of the first gear set, the second gear of the fourth gear set and the third gear of the fifth gear set are each selectively connectable for common rotation with the second countershaft.

In still another aspect of the present invention, the dual clutch assembly has a clutch housing connectable to an engine output, a first clutch configured to selectively connect the clutch housing to the first transmission input member and a second clutch configured to selectively connect the clutch housing to the second transmission input member. The clutch housing is rotationally supported within the transmission housing.

In still another aspect of the present invention, the first synchronizer assembly is configured to selectively connect the second gear of the second gear set to the first countershaft to establish a fourth gear ratio when the second clutch of the dual clutch assembly is engaged to connect the clutch housing of the dual clutch to the second transmission input member.

In still another aspect of the present invention, the second synchronizer assembly is configured to selectively connect the second gear of the first gear set to the second countershaft to establish a second gear ratio when the second clutch of the dual clutch assembly is engaged to connect the clutch housing of the dual clutch to the second transmission input member.

In still another aspect of the present invention, the third synchronizer assembly is configured to selectively connect the second gear of the fifth gear set to the first countershaft to establish a first gear ratio and the second gear of the third gear set to the first countershaft to establish a fifth gear ratio when the first clutch of the dual clutch assembly is engaged to connect the clutch housing of the dual clutch to the first transmission input member.

In still another aspect of the present invention, the fourth synchronizer assembly is configured to selectively connect the second gear of the fourth gear set to the second countershaft to establish a third gear ratio and the third gear of the fifth gear set to the second countershaft to establish a reverse gear ratio when the first clutch of the dual clutch assembly is engaged to connect the clutch housing of the dual clutch to the first transmission input member.

DESCRIPTION

Referring toFIG. 1, a multiple speed transmission is generally indicated by reference number10. The transmission10is connectable to an input member12and includes an output member or gear14. In the present embodiment, the input member12is a shaft and the output member14is a gear, however those skilled in the art will appreciate that the input member12may be components other than shafts and the output member14may be a component, such as a shaft, other than a gear.

The input member12is continuously connected with an engine (not shown) or other torque producing machine to provide a driving torque to input member12. The output member or gear14rotatably drives a final drive assembly16. The final drive assembly16transfers torque delivered by output member14to first and second side axles17,18, and on to road wheels (not shown) coupled to side axles17,18.

The transmission10includes a housing19that at least partially encloses a gearing arrangement20. The gearing arrangement20includes various shafts or members, co-planar intermeshing gear sets, a dual clutch assembly, and selectively engageable synchronizers, as will be described herein. For example, the gearing arrangement20includes a first shaft or transmission input member22, a second shaft or transmission input member24, a first countershaft26, and a second countershaft28. The second shaft or transmission input member24is a sleeve shaft that is concentric with and overlies the first shaft or transmission input member22. The first countershaft26and the second countershaft28are each spaced apart from and parallel with the first and second shaft or transmission input members22,24. The first and second shafts22,24define a first axis of rotation, the first countershaft26defines a second axis of rotation and the second countershaft28defines a third axis of rotation. Shaft members22,24, the first and second countershafts26,28are rotatably supported by bearings30a,30b,30c,30d,30eand30f.

A dual clutch assembly32is connected between the input member12and the first and second shaft or transmission input members22,24. The dual clutch assembly32includes a clutch housing34that is configured to connect or engage for common rotation with input member12. Further, the dual clutch assembly32has first and second clutch elements or hubs36and38. Clutch elements36and38together with the clutch housing34are configured to form a friction clutch, as is known in the art as a dual clutch. More specifically, clutch elements36,38and the clutch housing34have friction plates mounted thereon or otherwise coupled thereto that interact to form a friction clutch. The clutch element36is connected for common rotation with the first shaft or transmission input member22and the clutch element38is connected for common rotation with the second shaft or transmission input member24. Thus, selective engagement of clutch element36with the clutch housing34connects the input member12for common rotation with the first shaft or transmission input member22. Selective engagement of clutch element38with the clutch housing34connects the input member12for common rotation with the second shaft or transmission input member24.

The gearing arrangement20also includes a plurality of co-planar, meshing gear sets40,50,60,70and80. Co-planar gear set40includes gear42and gear44. Gear42is rotatably fixed and connected for common rotation with the second shaft or transmission input member24. Gear44is selectively connectable for common rotation with the second countershaft member28and meshes with gear42. It should be appreciated that gear42may be a separate gear structure fixed to the second shaft member24or gear teeth/splines formed on an outer surface of the second shaft member24without departing from the scope of the present invention. Gear set40is disposed adjacent a wall47of the transmission housing19that is on a front or side of the transmission10proximate the dual clutch assembly32.

Co-planar gear set50includes gear52and gear54. Gear52is rotatably fixed and connected for common rotation with the second shaft member24and meshes with gear54. Gear54is selectively connectable for common rotation with the first countershaft member26. Gear set50is positioned adjacent gear set40.

Co-planar gear set60includes gear62and gear64. Gear62is rotatably fixed and connected for common rotation with the first shaft member22and meshes with gear64. Gear64is selectively connectable for common rotation with the first countershaft member26. Gear set60is disposed adjacent gear set50.

Co-planar gear set70includes gear72and gear74. Gear72is rotatably fixed and connected for common rotation with the first shaft or transmission input member22and meshes with gear74. Gear74is selectively connectable for common rotation with the second countershaft member28. Gear set70is positioned adjacent gear set60.

Co-planar gear set80includes gear82, gear84and reverse gear90. Gear82is rotatably fixed and connected for common rotation with the first shaft or transmission input member22and meshes with gear84. Gear84is selectively connectable for common rotation with the first countershaft member26. Gear set80is positioned between gear set70and an end wall88of the transmission housing19. Reverse gear90is axially aligned with gear84and is selectively connectable for common rotation with the second countershaft member28. Further, reverse gear90meshes with gear84of gear set80. Reverse gear90is located between gear set70and end wall88.

Further, a first countershaft transfer gear100is rotatably fixed and connected for common rotation with the first countershaft member26. A second countershaft transfer gear110is rotatably fixed and connected for common rotation with the second countershaft member28. First countershaft transfer gear100is configured to mesh with output member14and the second countershaft transfer gear110is configured to mesh with output member14. However, the first countershaft transfer gear100and the second countershaft transfer gear110do not mesh with each other. The first countershaft transfer gear100is disposed between the co-planar gear set40and end wall47of the transmission housing19. The second countershaft transfer gear110is disposed between gear set40and end wall47of the transmission housing19. The output member14is co-planar with first and second countershaft transfer gears100,110and positioned between the gear set50and end wall47of the transmission housing19.

The transmission10further includes a plurality of selectively engageable synchronizer assemblies150,152,154and156. Synchronizers150and152are a single sided synchronizer that generally include a shift fork (not shown) that is bi-directionally translated by an actuator (not shown) into either an engaged position or a neutral or disengaged position. In the present embodiment, synchronizer150is selectively actuatable to connect gear54for common rotation with the first countershaft member26and synchronizer152is selectively actuatable to connect gear44for common rotation with the second countershaft member28. In a preferred embodiment, synchronizers150,152have only one actuator.

Synchronizers154and156are double sided synchronizers and generally include a shift fork (not shown) that is bi-directionally translated by an actuator (not shown) into at least two engaged positions and a neutral or disengaged position. In the present embodiment, synchronizer154is selectively actuatable to connect for common rotation gear64with the first countershaft26and is selectively actuatable to connect for common rotation gear84with the first countershaft26. Synchronizer156is selectively actuatable to connect for common rotation gear74with the second countershaft member28and is selectively actuatable to connect for common rotation reverse gear90with the second countershaft member28.

The transmission10is capable of transmitting torque from the input shaft12to the output gear member14in at least five forward torque ratios and at least one reverse torque ratio. Each of the forward torque ratios and the reverse torque ratio is attained by selective engagement of the dual clutch assembly32and one or more of the synchronizer assemblies150,152,154and156. Those skilled in the art will readily understand that a different speed ratio is associated with each torque ratio.

It should be appreciated that each individual gear set40,50,60,70and80provides one or more forward and/or reverse gear ratios upon selective engagement of the synchronizer assemblies150,152,154and156. It should also be appreciated that a particular forward or reverse speed ratio may be achieved by different combinations of synchronizer and associated gear sets without departing from the scope of the present invention.

For example, to establish the reverse torque ratio, clutch element36is engaged and synchronizer156is activated. Clutch element36couples the input member12with the first shaft member22. Synchronizer156connects reverse gear90to the second countershaft member28. More specifically, input torque from the input shaft12is transferred through the dual clutch assembly32to the first shaft member22, through gear82to gear84, through gear84to reverse gear90, from gear90to the second countershaft member28to second countershaft transfer gear110and from second countershaft transfer gear110to the output member14.

To establish a first forward torque ratio (i.e. a 1st gear), clutch element36is engaged and synchronizer154is activated. Clutch element36couples the input member12with the first shaft member22. Synchronizer154couples gear84to the first countershaft member26. Input torque from the input member12is transferred through the dual clutch assembly32to the first shaft member22to gear82. Gear82transfers torque to gear84which transfers the torque to the first countershaft member26through synchronizer154and to first countershaft transfer gear100and then from first countershaft transfer gear100to the output member14.

To establish a second forward torque ratio (i.e. a 2nd gear), clutch element38is engaged and synchronizer152is activated. Clutch element38couples the input member12to the second shaft member24which rotates gear42. Synchronizer152couples gear44to the second countershaft member28. Accordingly, input torque from the input member12is transferred through the dual clutch assembly32to the second shaft member24, through gear42to gear44, from gear44to synchronizer152, from synchronizer152to the second countershaft member28and from the second countershaft transfer gear110to the output member14.

To establish a third forward torque ratio (i.e. a 3rd gear), clutch element36is engaged and synchronizer156is activated. Clutch element36couples the input member12to the first shaft member22which rotates gear72. Synchronizer156couples gear74to the second countershaft member28. Thus, input torque from the input member12is transferred through the dual clutch assembly32to the first shaft member22, through gear72to gear74, through gear74to synchronizer156, from synchronizer156to the second countershaft member28, from the second countershaft member28to the second countershaft transfer gear110and then from second countershaft transfer gear110to the output member14.

To establish a fourth forward torque ratio (i.e. a 4th gear), clutch element38is engaged and synchronizer150is activated. Clutch element38couples the input member12to the second shaft member24which rotates gear52. Synchronizer150couples gear54to the first countershaft member26. Thus, input torque from the input member12is transferred through the dual clutch assembly32to the second shaft member24to gear52, then from gear52to gear54, from gear54to synchronizer150, from synchronizer150to the first countershaft member26, from the first countershaft member26to first countershaft transfer gear100and then from first countershaft transfer gear100to the output member14.

To establish a fifth forward torque ratio (i.e. a 5th gear), clutch element36is engaged and synchronizer154is activated. Clutch element36couples the input member12to the first shaft member22which rotates gear62. Synchronizer154couples gear64to the first countershaft member26. Input torque from the input member12is transferred through the dual clutch assembly32to the first shaft member22, from first shaft member22to gear62, from gear62to gear64, from gear64to the first countershaft member26through synchronizer154, to first countershaft transfer gear100and from first countershaft transfer gear100to the output member14

Again, it should be appreciated that any one of the gear sets of gear sets40,50,60,70and80may be changed to produce a certain forward and reverse torque ratio without departing from the scope of the present invention.

The present invention contemplates that a variety of torque ratios (i.e., the ratio of torque of the output member14to the input member12) are achievable through the selection of tooth counts of the gears of the transmission10. This arrangement provides the opportunity to achieve reduced transmission length in comparison with other transmissions and maximizes final drive ratio flexibility.