Vehicle transmission and drive systems

Abstract

A transmission includes: a transmission main housing; an intermediate plate, the intermediate plate being fastened to the transmission main housing; and a rear housing, the rear housing being attached to the intermediate plate and / or attached to the main housing via fasteners passing through the intermediate plate. An input shaft is connected to an extension shaft, the extension shaft including a plurality of auxiliary transmission gears that can be selectively coupled to the extension shaft. A main shaft is rotatably supported by a shift shaft and a shift shaft bearing, and includes a plurality of main case gears that can be selectively coupled to the main shaft. The shift shaft is drivingly connected to the main shaft and provides input to a planetary gear assembly. The extension shaft is supported at a first end by a bearing assembly within a partition wall of the main transmission housing, and a second end by a bearing assembly disposed within the aperture in the shift shaft.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Application No. 62 / 942,721, filed on December 2, 2019. The entire disclosure of the above application is incorporated herein by reference. Technical Field

[0003] The present disclosure relates to a vehicle transmission for a commercial vehicle. Background Art

[0004] This section provides background information related to the present disclosure which is not necessarily prior art.

[0005] The transmission plays a vital role in transferring the power provided by the prime mover to the final load. The transmission is used to provide a speed ratio change between the prime mover output (e.g., a rotating shaft) and the load drive input (e.g., a rotating shaft coupled to a wheel, a pump, or other device responsive to the drive shaft). The ability to provide selectable speed ratios allows the transmission to amplify torque, maintain prime mover speed and load speed within the range desired by those devices, and selectively disconnect the prime mover from the load under certain operating conditions.

[0006] Transmissions present many conflicting constraints and operating requirements. For example, the transmission must be able to provide a desired range of torque multiplication while still handling the input torque requirements of the system. Additionally, from an overall system perspective, the transmission represents an overhead device—the space occupied by the transmission, the weight, and the interface requirements of the transmission are all aspects of overhead for the system designer. Transmission systems are highly complex, and they take a long time to design, integrate, and test; therefore, the transmission also often needs to meet the expectations of the system integrator relative to previous or historical transmissions. For example, in the long run, it may be desirable to reduce the space occupied by the transmission, but for a given system design, it may be more desirable to occupy the same space as the previous generation transmission or as close as possible to the previous generation transmission.

[0007] Previously known transmission systems suffer from one or more disadvantages within the system as described below. To manage noise, robustness, and structural integrity issues, previously known high output transmission systems use steel for the housing of the transmission. Additionally, thrust loads through the transmission, noise generated by the gears, and installation issues (such as complex gear timing issues) require a robust and potentially overdesigned system in terms of housing, bearings, and / or mounting procedures. Thus, there remains a need for improved designs of high output transmissions, particularly truck transmissions.

[0008] In cutting edge split transmissions, the input shaft length within the transmission gearbox is lengthened with additional splitter gears, resulting in a longer cantilevered input shaft inside the gearbox. This cantilevered length becomes excessive as the splitter ratios become larger, such as 3x3x2 and 4x2x2 architectures. Since the front of the input shaft is positioned by the engine flywheel guide bearing, which may be misaligned, the increased length of the internal cantilevered shaft increases its radial displacement relative to the gearbox centerline. Without significant improvements in the manufacturing tolerances of both the engine and the transmission, it is not possible to achieve the required input shaft to gearbox centerline alignment with a longer input shaft. Excessive radial displacement of the splitter drive gears relative to the gearbox centerline reduces the robustness of the design. Furthermore, for dual countershaft transmissions, the long cantilevered input shaft radial displacement makes it impossible for these gears to operate with balanced power transfer to / from each countershaft.

[0009] This radial displacement of the cantilever also prefers to use only the front-most auxiliary transmission drive gear for PTO operation, where unbalanced radial loads and associated deflections are encountered and must be improved. Other auxiliary transmission gear sets further back are not preferred for PTO operation because there are design difficulties in dealing with the unbalanced load of the PTO and the resulting deflection / misalignment. PTO applications are generally limited to vehicle stationary operating modes, and the speed ratio selection available for vehicle mobile operation is limited. When the PTO is engaged to enter the vehicle mobile mode, it is usually impossible to switch between speed ratios. If the design solution of the PTO mode is implemented under all auxiliary transmission speed ratios, the intermediate shaft PTO speed will change relative to the engine speed depending on which of the 3 auxiliary transmission speed ratios (3x3x2) or 4 auxiliary transmission speed ratios (4x2x2) is utilized. These different intermediate shaft PTO speeds may bring undesirable complexity to the vehicle operator.

[0010] Another challenge with a 3x3x2 or 4x2x2 front splitter transmission is maintaining efficient lubricant flow for each ratio. For a lubricant pump driven by the intermediate shaft, flow is established to meet the needs of the slowest auxiliary transmission ratio, and excessive flow is encountered when operating in the faster auxiliary transmission ratios. Therefore, the optimum mechanical efficiency of the lubrication system is not achieved in all ratios.

[0011] In a transmission constructed with dual countershafts, it is specified that all gears on the countershafts be aligned within the available manufacturing tolerance capabilities so that both countershafts have similar gear orientations. The 2 countershafts orient the sunshaft gears where they meet approximately on the gearbox centerline, with the variation (radial float) from the true centerline depending on the countershaft gear alignment tolerances. A gearbox configuration that accommodates this radial float is necessary in a dual countershaft transmission design. In a transmission constructed with helical gears, thrust loads must be handled in both the drive torque and coasting (engine braking) torque directions. The bearings between the gears / shafts in the sunshaft location must be robust to these speeds and thrust loads, and must be implemented with a device that also handles the sun gear / shaft radial float caused by the alignment tolerances of the countershafts in terms of the gears they meet.

[0012] The conventional architecture approach to a 3x3x3 18 speed transmission with dual countershafts presents the following design challenges: How should the input shaft and 3 front auxiliary transmission drive gears be configured, when must the sliding clutch / sliding sleeve for the synchronizer be spaced apart and independently coupled to the input shaft so as not to have excessive radial displacement of the gearbox center axis due to the alignment of the input shaft via the engine flywheel forward guide bearing position. Another question is how should the auxiliary power take-off be configured so that there is a consistent speed ratio relative to the engine RPM, while encountering 3 different speed ratios relative to the engine depending on the auxiliary transmission drive gear ratio at the countershaft? Likewise, how should the lube oil pump be configured to provide a consistent speed ratio with the engine regardless of the auxiliary transmission gear ratio selected? Another question is how should the PTO mode be configured so that operation is feasible when the vehicle is in mobile operation at any gear ratio? How should the input design configuration accommodate the unbalanced radial loads from the PTO mode drive gears? How should the front auxiliary transmission drive gears and input shaft be configured when radial displacement is required in the unloaded auxiliary transmission drive gears when the opposing drive gears are in the load path, but must be constrained to the shaft center when operating the PTO mode? How should the architecture accommodate helical gear drive thrust loads and differential conditions? How should the PTO drive be configured so that the center distance between the PTO axis and the output shaft axis becomes large enough to accommodate the radial clearance between the output end yoke or output flange and the PTO output yoke or PTO direct mounted pump? Summary of the invention

[0013] This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.

[0014] In view of the design issues identified above, the present disclosure utilizes a short input shaft that is aligned with the engine flywheel guide bearing and concentrically splined to an extension shaft coaxial with the gearbox. The 3 front auxiliary transmission drive gears can be coupled to the extension shaft via a slip clutch. The extension shaft can be constructed of one or more links to best accommodate manufacturing methods. In a dual intermediate shaft design, the thrust roller bearing race is maintained on the extension shaft center axis to minimize radial displacement while permitting the 3 auxiliary transmission drive gears and the main shaft gear to float radially.

[0015] The design of the present disclosure attaches an independent PTO drive gear directly to the extension shaft and uses an independent driven gear / shaft for the PTO output device. The PTO output end can be in at least 2 forms, namely, a bottom mounted gear meshing interface form or a rear mounted shaft coupling interface form. This configuration provides a single speed ratio of the PTO relative to the engine RPM. In addition, the present disclosure configures the PTO rear shaft to drive the transmission lubricating oil pump at a single speed ratio relative to the engine. When the main input clutch is engaged with the engine, this transmission lubricating oil pump is activated in all transmission states. The present disclosure attaches an independent PTO drive gear directly to the extension shaft and uses an independent driven gear / shaft for the PTO output device. This configuration makes the PTO mode available at all gear ratios. The present disclosure further attaches an independent PTO drive gear directly to the extension shaft. Each end of the extension shaft should be configured to be supported by bearings and / or other concentric shafts to absorb radial PTO mode loads. When in the PTO moving mode, the radial PTO mode loads to the extension shaft have negligible interaction with the gear ratio loads. The PTO driven gear should be attached to a shaft mounted on bearings, which in turn is attached directly or indirectly to the gearbox housing.

[0016] The present disclosure introduces significant radial clearance between the extension shaft and the front auxiliary transmission drive gear to accommodate radial float. The unloaded auxiliary transmission drive gear requires radial float when the opposing auxiliary transmission drive gear is in the load path in operation. The PTO radial load observed by the attached extension shaft is independent of auxiliary transmission gear selection.

[0017] The present disclosure incorporates two thrust bearings, one thrust bearing between the second and third auxiliary transmission drive gears, and a second thrust bearing between the third auxiliary transmission drive gear and the main shaft to handle the helical gear drive thrust loads and the differential conditions of the normal engine drive torque mode. The present disclosure incorporates extension shaft ball bearings and main shaft ball bearings to accommodate thrust for the engine brake torque mode. Thrust for the engine brake mode can also be accommodated by the auxiliary transmission section thrust bearing, but this depends on the operating ratio. The present disclosure incorporates significant radial float in the third auxiliary transmission drive gear / driven gear interface relative to its mating thrust bearing race.

[0018] The present disclosure also incorporates an extended center distance for the PTO driven gear / shaft output to accommodate radial clearance between the output fork or output flange and the rear mounted PTO output fork or direct mounted pump. The extended center distance of this PTO is independent of the intermediate shaft center distance.

[0019] Further areas of applicability will become apparent from the description provided herein.The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

[0021] Figure 1 is a perspective view of the transmission;

[0022] Figure 2A is a horizontal cross-sectional view of a transmission assembly according to the principles of the present disclosure;

[0023] Figure 2B is a vertical cross-sectional view of a transmission assembly according to the principles of the present disclosure;

[0024] Figure 3 is a partial cross-sectional view of the input shaft, extension shaft, main shaft and dual countershaft gear train system of the present disclosure, with the housing removed for illustration purposes;

[0025] Figure 4 is a left rear perspective view of a main transmission housing according to the principles of the present disclosure;

[0026] Figure 5 is a right side rear perspective view of a main transmission housing according to the principles of the present disclosure;

[0027] Figure 6 is a bottom rear perspective view of a main transmission housing according to the principles of the present disclosure;

[0028] Figure 7 is a cutaway perspective view of a main transmission housing according to the principles of the present disclosure;

[0029] Figure 8 is a front perspective view of a machined center plate of a transmission housing;

[0030] Fig. 9 is a front perspective view of a machined center plate of a transmission housing with a reverse idler gear mounted thereon;

[0031] Fig.10is an exploded perspective view of a partial mounting section of a PTO driven gear, shaft, bearing, support housing and main transmission housing;

[0032] Fig.11 yes Fig.10 A cross-sectional view of the PTO driven gear support assembly and a partial main transmission case mounting section is shown;

[0033] Fig.12 is a cross-sectional view of a rear mounted power take-off quill and coupling unit;

[0034] Fig.13 is a cross-sectional view of a power take-off device connected to a rear mounted power take-off quill and coupling unit in accordance with the principles of the present disclosure;

[0035] Fig.14 is a cross-sectional view of an input shaft, an alternative two-piece extension shaft, a main shaft, and a thrust bearing according to a first alternative embodiment;

[0036] Fig.15 is a cross-sectional view of an input shaft, an alternative two-piece extension shaft, a main shaft, and a thrust bearing according to a second alternative embodiment;

[0037] Fig.16 is a cross-sectional view of an input shaft, an alternative two-piece extension shaft, a main shaft, and a thrust bearing according to a third alternative embodiment;

[0038] Fig.17 is a cross-sectional view of an input shaft, an alternative two-piece extension shaft, a main shaft, and a thrust bearing according to a fourth alternative embodiment; and

[0039] Fig.18 is a cross-sectional view of an input shaft, an alternative two-piece extension shaft, a main shaft, and a thrust bearing according to a fifth alternative embodiment.

[0040] Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings. DETAILED DESCRIPTION

[0041] Example embodiments will now be described more fully with reference to the accompanying drawings.

[0042] Example embodiments are provided so that the present disclosure will be complete and will fully convey the scope to those skilled in the art. Many specific details, such as examples of specific components, devices, and methods, are set forth to provide a thorough understanding of the embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that the example embodiments may be implemented in many different forms, and that they should not be construed as limiting the scope of the present disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known techniques are not described in detail.

[0043] refer to Figure 1 , shows a perspective view of a transmission 10, which includes a main housing 12, an intermediate plate 14, and a rear housing 16. The transmission 10 is assembled with the intermediate plate 14 assembled to the rear end of the main housing 12, and the rear housing 16 is mounted to the intermediate plate 14. An integrated actuator housing 18 is mounted to the main housing 12.

[0044] like Figure 2A , the transmission 10 is schematically shown in a horizontal cross-sectional view. The example transmission 10 is capable of providing power throughput from a prime mover (not shown) interfaced with a clutch unit 22 (schematically shown) to an input shaft 23, from the input shaft 23 to an extension shaft 24, from the extension shaft 24 to a main shaft portion 26, from the main shaft portion to a rangeshaft portion 28, and from the rangeshaft portion 28 to an output shaft assembly 30.

[0045] The example transmission 10 is operable to adjust the torque multiplication factor throughout the transmission to engage and disengage the clutch unit 22 from a prime mover (not shown), and / or to position the transmission 10 into a neutral position in which torque is not transferred from the clutch unit 22 to the output shaft assembly 30 even if the clutch unit 22 is engaged to a prime mover.

[0046] Further references Figure 2A and Figure 2B A clutch engagement fork 32 is provided for engagement of the clutch unit 22 with the prime mover. The exemplary clutch engagement fork 32 is operably coupled to a clutch actuator at a first end. In certain embodiments of the present disclosure, any type of clutch actuation may be utilized, including a concentric clutch actuator (not shown) and / or another type of linear clutch actuation device.

[0047] The example transmission 10 includes an auxiliary transmission section 33a, a main case section 33b, and a range gear section 33c to provide a plurality of gear ratios. The auxiliary transmission section 33a includes a first auxiliary transmission gear 34, a second auxiliary transmission gear 36, and a third auxiliary transmission gear 38, each selectively coupled to the extension shaft 24. The inclusion of the first auxiliary transmission gear 34, the second auxiliary transmission gear 36, and the third auxiliary transmission gear 38 allows additional different gear ratios to be provided by the extension shaft 24. The first auxiliary transmission gear 34 can be rotatably engaged with the extension shaft 24 through a first synchronizer sleeve 35, while the second auxiliary transmission gear 36 and the third auxiliary transmission gear 38 can be selectively rotatably engaged with the extension shaft 24 through a second double-sided synchronizer sleeve 39.

[0048] The main case section 33b of the example transmission 10 also includes a plurality of main case gears 40, 42, 44 selectively coupled to the main shaft portion 26. The main case gear 40 can be rotatably engaged with the main shaft 26 via a third synchronizer sleeve 41, while the main case gears 42 and 44 can be selectively rotatably engaged with the main shaft 26 via a fourth double-sided synchronizer sleeve 45.

[0049] The shift gear section 33c of the example transmission 10 also includes a planetary gear assembly 46 that couples the shift shaft portion 28 to the output shaft assembly 30 with at least two selectable gear ratios between the shift shaft portion 28 and the output shaft assembly 30. In particular, as is known in the art, the planet gear carrier of the planetary gear assembly 46 can be engaged to the sun gear to provide a 1:1 gear ratio, or can be disengaged to provide a gear reduction through a planetary system.

[0050] The example transmission 10 also includes at least one and preferably two countershafts 48a, 48b having three adjustment gears 50, 52, 54 within the auxiliary transmission section 33a and drivingly engaged with the respective first auxiliary transmission gear 34, second auxiliary transmission gear 36 and third auxiliary transmission gear 38 on the extension shaft 24. The countershafts 48a, 48b also include three adjustment gears 56, 58, 60 within the main case section 33b and drivingly engaged with the respective first main case gear 40, second main case gear 42 and third main case gear 44 selectively coupled to the main shaft portion 26. With three gears in the auxiliary transmission section 33a, three gears in the main case section 33b and two gear ratios provided by the shift gear section 33c, the transmission 20 provides a 3×3×2 transmission architecture operable to provide 18 practical and functional gear ratios. The number and selection of gears depends on the number of gear ratios desired for the transmission.

[0051] The transmission 10 includes a pair of reverse idler gears 62 (best shown in FIG. Fig. 9 ), the pair of reverse idler gears 62 engage with the adjustment gears 60 of the intermediate shafts 48a, 48b and the main case gear 44 of the main shaft portion 26. One or more intermediate shafts 48a, 48b thus selectively transmit forward or reverse power between the extension shaft 24 and the main shaft portion 26, depending on which gears are rotationally fixed to the extension shaft 24 and / or the main shaft portion 26 (via the clutch sleeve).

[0052] like Figure 2BAs shown in the vertical cross-sectional view of the transmission 10 in FIG. 1 , the transmission also includes a PTO drive gear 70 fixed to the extension shaft 24 for rotation therewith. The PTO drive gear 70 is disposed between the first auxiliary transmission gear 34 and the second auxiliary transmission gear 36 and engages with a PTO driven gear 72 mounted to a PTO shaft 74.

[0053] like Fig.10 and Fig.11 As best shown, the PTO shaft 74 and the PTO driven gear 72 are each supported by a PTO pillow block housing 76, which supports a pair of roller bearings 78 that rotatably support a PTO gear shaft 80. The PTO driven gear 72 is connected to the PTO gear shaft 80 by a semi-circular key 82. The PTO gear shaft 80 includes a pair of annular grooves 8 for receiving a pair of retaining rings 84 to secure the PTO gear shaft 80 within the roller bearings 78. Fig.11 As best shown, the PTO pillow block housing 76 may include an annular groove 86 for receiving a retaining ring 87 to secure the roller bearing 78 within the PTO pillow block housing 76. The PTO pillow block housing 76 is mounted to and supported by a base frame 88 that includes four mounting lugs 90 having threaded holes 92 to receive a plurality of mounting bolts 94 that extend through holes 96 in the PTO pillow block housing 76. Figure 2B The PTO shaft 74 is supported at its front end by the PTO pillow block housing 76 and at its rear end by a bearing 98 which is supported by a hole 99 ( Figure 8 and Fig. 9 )Inside.

[0054] refer to Figures 4 to 7 The main housing 12 includes a one-piece generally annular wall structure 100 made of cast aluminum. The front end 102 of the main housing 12 may define a clutch chamber 104 ( Figure 2A , Figure 2B ), the clutch chamber 104 is used to receive the clutch engagement fork 32 of the clutch unit 22. The rear end 106 of the main housing 12 defines a transmission main chamber 108, which is used to receive the second main shaft portion 26 and the shift shaft portion 28 and the intermediate shafts 48a, 48b. Figure 2A , Figure 2B and Figure 7 As best shown, the partition wall 109 is disposed between the clutch chamber 104 and the transmission main chamber 108 and is integrally formed with the one-piece generally annular wall structure 100. The partition wall 109 includes a plurality of openings 109a, 109b, 109c ( Figure 2A), the plurality of openings 109a, 109b, 109c are used to receive and support the first ends of the extension shaft 24 and the intermediate shafts 48a, 48b.

[0055] The intermediate plate 14 includes a plurality of openings 14a, 14b, 14c for receiving and supporting the main shaft 26 and the shift shaft 28 and the second ends of the intermediate shafts 48a, 48b. The extension shaft 24 is supported at the front end by a bearing 150 disposed in an opening 109a in the partition wall 109. The rear end of the extension shaft is supported by a roller bearing 152 disposed in an aperture in the shift shaft portion 28. The front end of the shift shaft portion 28 is supported in the opening 14a of the intermediate plate 14 by a bearing assembly 154. The main shaft 26 is rotatably supported on the extension shaft 24. The rear end of the main shaft has an external spline that engages with an internal spline on the front end of the shift shaft 28 radially within the bearing support 154.

[0056] refer to Figure 3 , the extension shaft 24 includes internal splines 804, which are connected to the external splines 23a of the input shaft 23. The front end of the extension shaft 24 is supported by the bearing assembly 150. The front end of the extension shaft 24 also includes external splines 806, which are connected to the internal splines 308 of the clutch hub 810. The first auxiliary transmission gear 34 is loosely supported on the extension shaft 24 by a needle bearing 812, and the second auxiliary transmission gear 36 is loosely supported on the extension shaft 24 by a needle bearing 814. The first auxiliary transmission gear 34 is set against the clutch hub 810 and against the PTO drive gear 70. The second auxiliary transmission gear 36 is set against the PTO drive gear 70 and against the clutch hub 816, which is splined to the extension shaft 24. A thrust washer 818 is provided between the clutch hub and the first thrust bearing 800, which has a cylindrical roller 820 set against the thrust race 822. The third auxiliary transmission gear 38 is supported on the thrust race 822 with radial clearance. The slip clutch 824 is supported on the clutch hub 816 and can engage with the second auxiliary transmission gear 36 and the third auxiliary transmission gear 38. The second thrust bearing 826 has a cylindrical roller 828 disposed against the thrust race 822. The thrust washer 830 is disposed against the second thrust bearing 826 and against the race 832. The race 832 includes a tapered rear surface disposed against the spherical washer 836. The spherical washer 836 is disposed against the clutch hub 838 and the main shaft 26. The clutch hub 838 is splined to the main shaft 26. The double-sided slip clutch 41 is mounted to the clutch hub 838.

[0057] The shift gear shaft 28 includes internal splines 842 that engage external splines 844 of the main shaft 26. The main case gear 40 is positioned by the clutch hub 838 and the washer 850, and is engaged to the clutch hub and the washer by the sliding clutch 41. The second main case gear 42 is selectively engaged to the main shaft 26, and is positioned by the washer 850 and the clutch hub 846 that supports the sliding clutch 45. The third main case gear is selectively engaged to the main shaft 26, and is positioned by the washer 852, the spacer 854 and the washer 856, and the clutch hub 846 that supports the sliding clutch 45.

[0058] refer to Figures 4 to 6 The one-piece generally annular wall structure 100 of the main housing 12 has a front mounting flange 110 and a rear mounting flange 112, each having a plurality of holes or apertures 114 to receive fasteners therein. The annular wall structure 100 may have a wall thickness of between 5.0 mm and 7.0 mm, and preferably 6.0 mm, in order to provide a reduced weight aluminum housing.

[0059] To further strengthen the annular wall structure 100, a plurality of axially extending ribs 116 may extend longitudinally from the front end 102 to the rear end 106 of the main shell 12. The axially extending ribs 116 provide part structure, reduce the frequency of large panels of the main shell 100, and support material flow throughout the structure during casting of the main shell 100. In addition, a plurality of angled extending ribs 118 extend diagonally between adjacent axially extending ribs of the plurality of axially extending ribs 116. By "diagonally" is meant that the plurality of angled extending ribs 118 extend from the axially extending ribs 116 at an acute angle (not a right angle). The angled extending ribs 118 provide part structure by connecting the longitudinal ribs 116 and further aid in material flow during casting of the main shell 100, thereby reducing turbulence and mitigating porosity.

[0060] like Figure 4 As shown, the one-piece generally annular wall structure 100 may include a top wall portion 120, a left side wall portion 122, a right side wall portion 124, and a bottom wall portion 126. The top wall portion 120 may include an actuator docking opening 128 having an actuator wall structure 130 extending radially outward from the top wall portion 120 of the generally annular wall structure 100. The actuator wall structure 130 may include a plurality of apertures 132 for receiving fasteners to fasten the actuator housing 18 within the actuator docking opening 128. Figure 6As best shown, the bottom wall portion 126 may include a PTO docking opening 136 having a PTO wall structure 138 extending radially outward from the bottom wall portion 126 of the generally annular wall structure 100. The PTO wall structure 138 may include a plurality of apertures 140 for receiving fasteners to fasten a PTO cover 142 over the PTO docking opening 136. Figure 2B As shown, the PTO cover 142 may include a cover body that is configured to enclose a portion of the PTO driven gear 72 so as to be in close proximity to the front, rear, and periphery of a portion of the PTO driven gear 72 to limit the resistance of oil and air to the rotating PTO driven gear 72 (i.e., windage).

[0061] refer to Figure 7 , shows a cutaway section of the main housing 12 including a plurality of undulations 144 disposed in the bottom wall portion 126 and the right side wall portion 124. The undulations 144 define an undulating surface and extend axially along the generally annular wall structure 100 and break up the large planar panels of the wall portions 126, 124 by providing additional strength and reduced frequency.

[0062] The design of the aluminum main housing 12 provides a reduced weight housing with the required strength and noise reduction. The aluminum main housing 12 is also economically castable.

[0063] refer to Figure 8 and Fig. 9 Now, the intermediate plate 14 of the transmission housing 10 will be described. Figure 8 As shown, the intermediate plate 14 includes a plate-like base 200 having a peripheral flange portion 202 extending around the plate-like base 200. The plate-like base 200 includes a central opening 14a for receiving the bearing 154 (best shown in FIG. Figure 2B The plate-like base 200 includes a pair of openings 14b, 14c laterally offset from the central opening 14a, and the pair of openings 14b, 14c are used to receive bearings 210 to support the intermediate shafts 48a, 48b. Fig. 9 As best shown, the intermediate plate 14 also includes two pairs of axially spaced reverse idler support bosses 212a, 212b for supporting the pair of reverse idler gears 62. The support bosses 212a are supported by a bridge wall including a pair of side ribs 216, a middle wall 218, and additional structural ribs 220 extending from the middle wall 218 to the peripheral flange 202.

[0064] like Fig. 9As shown, the reverse idler support bosses 212a, 212b each include an opening 226 that supports a reverse idler shaft 228 that supports a reverse idler gear 62. The reverse idler gears 62 each engage one of the adjustment gears 60 of the intermediate shafts 48a, 48b and engage the gear 44 of the first main shaft portion 26.

[0065] refer to Figure 2B , the PTO shaft 74 is drivingly connected to the pump impeller of a transmission lubricating oil pump 230 mounted to the center plate 14. The transmission lubricating oil pump 230 is driven by the PTO shaft 74 and provides lubrication from an oil pan 232 at the bottom of the transmission housing 12, 14, 16 to internal passages 234 within the extension shaft 24 and the shift shaft 28 and other components of the transmission.

[0066] Continue to refer Figure 2B The end of the PTO shaft 74 may further engage with a rear mounted PTO 240 extending from the rear housing 16 .

[0067] refer to Fig.12 and Fig.13 , the rear mounted PTO 240 is shown to include a PTO housing 242 having a PTO input shaft 244 rotatably supported by a bearing 246. The PTO input shaft 244 includes external splines 248 that are engageable with first internal splines 250 of a coupler sleeve 252. The coupler sleeve 252 is disposed within the PTO housing 242 and is biased toward a disengaged position by a spring 254. The coupler sleeve 252 is connected to a guide sleeve 256 that is slidably received within a retainer 258 that limits axial movement of the guide sleeve 256.

[0068] refer to Fig.13 , when the power take-off 260 is engaged with the rear mounted PTO 240, the spline shaft 262 is inserted into the second internal spline 264 of the coupler sleeve 252 to provide a driving connection with the power take-off 260. The coupler sleeve 252 can be pressed into engagement with the external splines 248 of the PTO input shaft 244 by the spline shaft 262 or another mechanism against the biasing force of the spring 254. In particular, the spline shaft 262 can include an external shoulder 266 that can engage the coupler sleeve 252 and press the coupler sleeve 252 into engagement with the PTO input shaft 244. When there is no PTO device 260 mounted to the rear mounted PTO 240, the PTO input shaft 244 does not engage the coupler sleeve 252 and moves by inertia / free motion relative to the coupler sleeve 252. The PTO input shaft 244 may be integrally formed with the PTO shaft 74 or may be connected thereto via splines 268 or other known connection systems.

[0069] The present disclosure utilizes a short input shaft 23 that is aligned with the engine flywheel guide bearing and concentrically splined to an extension shaft 24 coaxial with the transmission 10. Three front auxiliary transmission drive gears 34, 36, 38 can be connected to the extension shaft 24 via synchronizer sleeves 35 and 39. The extension shaft 24 can be composed of a single piece or a plurality of links to best accommodate the manufacturing and assembly process and to make the extension shaft rigid. In the dual intermediate shaft design, the thrust roller bearing races 800, 826 are maintained on the transmission center axis to minimize radial displacement while allowing the three auxiliary transmission drive gears 34, 36, 38 and the main shaft gears 40, 42, 44 to float radially. An independent PTO drive gear 70 is directly attached to the extension shaft 24, and an independent drive gear / shaft is used for the PTO output device. The PTO output end can be in at least two forms, including a bottom mounted gear meshing interface form or a rear mounted shaft coupling interface form. This configuration provides a single speed ratio for the power take-off (PTO) relative to the engine RPM. The PTO rear axle is also configured to drive the transmission lubricating oil pump at a single speed ratio relative to the engine speed. This transmission lubricating oil pump is active in all transmission states when the main input disc clutch 22 is engaged with the engine.

[0070] According to another aspect of the present disclosure, the power take-off system uses a PTO drive gear 70 directly attached to the extension shaft 24 and a separate driven gear 72 / shaft 74 for the power take-off device output. This configuration makes the power take-off mode available in all gear ratios.

[0071] According to yet another aspect of the present disclosure, each end of the extension shaft 24 is configured to be supported by bearings and / or concentric shafts to follow radial PTO mode loads. When in the PTO moving mode, the radial PTO mode loads to the extension shaft 24 have negligible interaction with the gear ratio loads. The PTO driven gear is attached to a shaft mounted on bearings, which in turn are directly or indirectly attached to the transmission housing.

[0072] According to yet another aspect of the present disclosure, the extension shaft introduces significant radial clearance with the first two auxiliary transmission drive gears 34, 36 to accommodate radial float. The unloaded auxiliary transmission drive gears require radial float when the opposing auxiliary transmission drive gears are in the load path in operation. The PTO radial loads followed by the attached extension shaft 24 are independent of auxiliary transmission gear selection.

[0073] The present disclosure incorporates two thrust bearings, one thrust bearing 800 between the second auxiliary transmission drive gear 36 and the third auxiliary transmission drive gear 38, and a second thrust bearing 826 between the third auxiliary transmission gear 38 and the main shaft 26 to handle the helical gear transmission thrust loads; and the main shaft ball bearing to accommodate the thrust for the engine braking torque mode. The thrust for the engine braking torque mode can also be accommodated by the auxiliary transmission section thrust bearing, but this depends on the operating ratio. The present disclosure provides for a significant radial float of the mating thrust bearing race relative to the third auxiliary transmission gear incorporated into the interface of the third auxiliary transmission gear 38.

[0074] The present disclosure also incorporates an extended center distance for the PTO driven gear output to accommodate radial clearance between the output and the fork or output flange and the rear mounted PTO output fork or direct mounted pump. The extended center distance of this PTO is independent of the intermediate shaft center distance.

[0075] refer to Fig.14 , an alternative arrangement of the input shaft 23 according to the first alternative embodiment has an alternative two-piece extension shaft 24a, 24b, a main shaft 26, a shift shaft 28 and thrust bearings 300, 302. The transmission 10 is capable of providing power throughput from a prime mover (not shown) interfaced with the clutch unit 22 to the input shaft 23, from the input shaft 23 to the two-piece extension shaft 24a, 24b, from the two-piece extension shaft 24a, 24b to the main shaft portion 26, from the main shaft portion 26 to the shift shaft portion 28, and from the shift shaft portion 28 to the output shaft assembly 30 (not shown in FIG. Fig.14 middle).

[0076] like Fig.14As shown, the secondary extension shaft 24b is press-fitted or otherwise connected to the primary extension shaft 24a. The primary extension shaft 24a includes internal splines 304, which are connected to the external splines 23a of the input shaft 23. The front end of the primary extension shaft 24a is supported by the bearing assembly 150. The primary extension shaft 24a also includes external splines 306, which are connected to the internal splines 308 of the clutch hub 310. The first auxiliary transmission gear 34 is loosely supported on the primary extension shaft 24a by needle bearings 312, and the second auxiliary transmission gear 36 is loosely supported on the primary extension shaft 24a by needle bearings 314. The first auxiliary transmission gear 34 is set against the clutch hub 310 and against the thrust washer 316. The second auxiliary transmission gear 36 is set against the thrust washer 316 and against the shoulder 318 of the primary extension shaft 24a. The axial end of the primary extension shaft 24a includes a pocket 320 that receives a wave spring 322 disposed against a thrust washer 324. A first thrust bearing 300 having a plurality of cylindrical rollers 326 is disposed against the thrust washer 324 and against a thrust race 328, which is supported on the secondary extension shaft 24b by a needle bearing 330. The third sub-transmission gear 38 is supported on the thrust race 328. The third sub-transmission gear 38 is supported with radial clearance relative to the thrust race 328. The thrust race 328 is supported on the extension shaft 24b by a needle bearing 330. A second thrust bearing 302 having a plurality of cylindrical rollers 332 is disposed against the thrust race 328. A race 334 is disposed against the second thrust bearing 302 and includes a tapered rear surface disposed against a spherical washer 336. A spherical washer 336 is disposed against the end of the spindle 26 .

[0077] The rear end of the secondary extension shaft 24b is supported by a needle bearing 340 in an aperture 338 of the shift shaft 28. The shift gear shaft 28 includes external splines 342 that engage internal splines 344 of a clutch hub 346. The internal splines 344 of the clutch hub 346 also engage external splines 348 of the main shaft 26. Both main case gears 40 and 42 are located on the main shaft 26, and the main case gear 44 is located on the clutch hub 346. A second slip clutch 350 is supported on the clutch hub 346 and includes clutch teeth 350a, 350b for engaging corresponding clutch teeth 42a, 44a of the main case gears 42, 44, respectively. The third slip clutch 352 includes internal splines 352a that engage with external splines 348 of the main shaft 26, and includes external clutch teeth 352b, 352c that can respectively engage with clutch teeth 38a, 40a of the auxiliary transmission gear 38 or the main case gear 40. The shift gear shaft 28 is supported by the ball bearing assembly 154, and the main case gear 44 is separated from the ball bearing assembly 154 by a spacer 354, which transfers the thrust load from the clutch hub 346 to the inner bearing race.

[0078] refer to Fig.15 , a second alternative arrangement of the input shaft 23 according to the second alternative embodiment has an alternative two-piece extension shaft 24a, 24b, a main shaft 26, a shift shaft 28 and thrust bearings 400, 402, wherein like reference numerals are used to refer to the same or similar elements. The transmission 10 is capable of providing power throughput from a prime mover (not shown) interfaced with the clutch unit 22 to the input shaft 23, from the input shaft 23 to the two-piece extension shaft 24a, 24b, from the two-piece extension shaft 24a, 24b to the main shaft portion 26, from the main shaft portion 26 to the shift shaft portion 28, and from the shift shaft portion 28 to the output shaft assembly 30 (not shown in FIG. Fig.15 (in Chinese). Fig.15As shown, the secondary extension shaft 24b is press-fitted or otherwise connected to the primary extension shaft 24a. The primary extension shaft 24a includes internal splines 404, which are connected to the external splines 23a of the input shaft 23. The front end of the primary extension shaft 24a is supported by the bearing assembly 150. The primary extension shaft 24a also includes external splines 406, which are connected to the internal splines 408 of the clutch hub 410. The first auxiliary transmission gear 34 is loosely supported on the primary extension shaft 24a by needle bearings 412, and the second auxiliary transmission gear 36 is loosely supported on the primary extension shaft 24a by needle bearings 414. The first auxiliary transmission gear 34 is set against the clutch hub 410 and against the thrust washer 416. The second auxiliary transmission gear 36 is set against the thrust washer 416 and against the shoulder 418 of the primary extension shaft 24a. The axial end of the primary extension shaft 24a includes a recess 420 that receives a wave spring 422 that is disposed against a first thrust washer 424. A first thrust bearing 400 having a plurality of cylindrical rollers 426 is disposed against the thrust washer 424 and against a second thrust washer 428 that is supported against a thrust race 429 that is supported on the secondary extension shaft 24b by a needle bearing 430. The third auxiliary transmission gear 38 is supported on the thrust race 429. The third auxiliary transmission gear 38 is supported with radial clearance relative to the thrust race 429. A second thrust bearing 402 having a plurality of cylindrical rollers 432 is disposed against the thrust race 429. A washer 434 is disposed against the second thrust bearing 402 and includes a tapered rear surface that is disposed against a spherical washer 436. The spherical washer 436 is disposed against a flat washer 438 which is disposed against the end of the spindle 26. A wave spring 440 is disposed in an end cavity 441 in the spindle 26 and is pressed against the flat washer 438.

[0079] The rear end of the secondary extension shaft 24b is supported by a needle bearing 444 in an aperture 442 of the shift gear shaft 28. The shift gear shaft 28 includes internal splines 446 that engage external splines 448 of the main shaft 26. Both main case gears 40 and 42 are located on the main shaft 26, and the main case gear 44 is located on the clutch hub 450. The second slip clutch 452 is supported on the clutch hub 450 and includes clutch teeth 452a, 452b for engaging corresponding clutch teeth 42a, 44a of the main case gears 42, 44, respectively. The third slip clutch 454 includes internal splines 454a that engage with external splines 448 of the main shaft 26, and includes external clutch teeth 454b, 454c that can engage with clutch teeth 38a, 40a of the auxiliary transmission gear 38 or the main case gear 40, respectively. The shift gear shaft 28 is supported by the ball bearing assembly 154, and the main case gear 44 is separated from the ball bearing assembly 154 by a spacer 456 which transfers the thrust load from the clutch hub 450 to the inner bearing race.

[0080] refer to Fig.16 , an alternative arrangement of the input shaft 23 according to the third alternative embodiment has an alternative two-piece extension shaft 24a, 24b, main shaft 26, shift shaft 28 and thrust bearings 500, 502. The transmission 10 is capable of providing power throughput from a prime mover (not shown) interfaced with the clutch unit 22 to the input shaft 23, from the input shaft 23 to the two-piece extension shaft 24a, 24b, from the two-piece extension shaft 24a, 24b to the main shaft portion 26, from the main shaft portion 26 to the shift shaft portion 28, and from the shift shaft portion 28 to the output shaft assembly 30 (not shown in FIG. Fig.16 (in Chinese). Fig.16As shown, the secondary extension shaft 24b is press-fitted or otherwise connected to the primary extension shaft 24a. The primary extension shaft 24a includes internal splines 504, which are connected to the external splines 23a of the input shaft 23. The front end of the primary extension shaft 24a is supported by the bearing assembly 150. The primary extension shaft 24a also includes external splines 506, which are connected to the internal splines 508 of the clutch hub 510. The first auxiliary transmission gear 34 is loosely supported on the primary extension shaft 24a by needle bearings 512, and the second auxiliary transmission gear 36 is loosely supported on the primary extension shaft 24a by needle bearings 514. The first auxiliary transmission gear 34 is set against the clutch hub 510 and against the thrust washer 516. The second auxiliary transmission gear 36 is set against the thrust washer 516 and against the shoulder 518 of the primary extension shaft 24a. The axial end of the primary extension shaft 24a includes a pocket 520 that receives a wave spring 522 disposed against a thrust washer 524. A first thrust bearing 500 having a plurality of cylindrical rollers 526 is disposed against the thrust washer 524 and against a thrust race 528, which is supported on the secondary extension shaft 24b by a needle bearing 530. The third auxiliary transmission gear 38 is supported with radial clearance relative to the thrust race 528. A second thrust bearing 502 includes a plurality of cylindrical rollers 532 disposed against the thrust race 528. A washer 534 is disposed against the second thrust bearing 502 and includes a tapered rear surface disposed against a spherical washer 536. The spherical washer 536 is disposed against the end of the main shaft 26.

[0081] The rear end of the secondary extension shaft 24b is supported by a needle bearing 544 in an aperture 542 of the shift gear shaft 28. The shift gear shaft 28 includes internal splines 546 that engage external splines 548 of the main shaft 26. Fig.15 In the embodiment of the present invention, both main case gears 40 and 42 are located on the main shaft 26, and the main case gear 44 is located on the clutch hub 550. The second slip clutch 552 is supported on the clutch hub 550 and includes clutch teeth 552a, 552b for engaging the corresponding clutch teeth 42a, 44a of the main case gears 42, 44, respectively. The third slip clutch 554 includes an internal spline 554a that engages with the external spline 548 of the main shaft 26, and includes external clutch teeth 554b, 554c that can engage with the clutch teeth 38a, 40a of the auxiliary transmission gear 38 or the main case gear 40, respectively. The shift gear shaft 28 is supported by the ball bearing assembly 154, and the main case gear 44 is separated from the ball bearing assembly 154 by a spacer 560, which transmits the thrust load from the clutch hub 550 to the inner bearing race.

[0082] refer to Fig.17 , an alternative arrangement of the input shaft 23 according to the fourth alternative embodiment has an alternative two-piece extension shaft 24a, 24b, a main shaft 26, a shift shaft 28 and thrust bearings 600, 602. The transmission 10 is capable of providing power throughput from a prime mover (not shown) interfaced with the clutch unit 22 to the input shaft 23, from the input shaft 23 to the two-piece extension shaft 24a, 24b, from the two-piece extension shaft 24a, 24b to the main shaft portion 26, from the main shaft portion 26 to the shift shaft portion 28, and from the shift shaft portion 28 to the output shaft assembly 30 (not shown in FIG. Fig.17 (in Chinese). Fig.17 As shown, the secondary extension shaft 24b is press-fitted or otherwise connected to the primary extension shaft 24a. The primary extension shaft 24a includes internal splines 604, which are connected to the external splines 23a of the input shaft 23. The front end of the primary extension shaft 24a is supported by the bearing assembly 150. The primary extension shaft 24a also includes external splines 606, which are connected to the internal splines 608 of the clutch hub 610. The first auxiliary transmission gear 34 is loosely supported on the primary extension shaft 24a by needle bearings 612, and the second auxiliary transmission gear 36 is loosely supported on the primary extension shaft 24a by needle bearings 614. The first auxiliary transmission gear 34 is set against the clutch hub 610 and against the PTO drive gear 616. The second auxiliary transmission gear 36 is set against the PTO drive gear 616 and against the shoulder 618 of the primary extension shaft 24a. The axial end of the primary extension shaft 24a includes a pocket 620 that receives a wave spring 622 disposed against a thrust washer 624. The first thrust bearing 600 has a plurality of cylindrical rollers 626 disposed against the thrust washer 624 and against a thrust washer 628 disposed against a bearing race 630. The bearing race 630 is supported on the secondary extension shaft 24b by a pair of needle bearings 632a, 632b. The third auxiliary transmission gear 38 is supported with radial clearance relative to the bearing race 630. The second thrust bearing 602 includes a plurality of cylindrical rollers 634 disposed against a thrust washer 636 disposed against the bearing race 630. A washer 638 is disposed against the second thrust bearing 602 and includes a tapered rear surface disposed against a spherical washer 640. The spherical washer 640 is disposed against the end of the spindle 26. A wave spring 642 is disposed in an end cavity 644 in the spindle 26 and presses against the spherical washer 640.

[0083] The rear end of the secondary extension shaft 24b is supported by a needle bearing 648 in an aperture 646 of the shift gear shaft 28. The shift gear shaft 28 includes internal splines 650 that engage external splines 652 of the main shaft 26. Both main case gears 42 and 44 are located on the main shaft 26. A second slip clutch 656 is supported on a clutch hub 654 and includes clutch teeth 656a, 656b for engaging corresponding clutch teeth 42a, 44a of the main case gears 42, 44, respectively. A third slip clutch 658 includes internal splines 658a that engage with external splines 652 of the main shaft 26, and includes external clutch teeth 658b, 658c that can engage with clutch teeth 38a, 40a of the auxiliary transmission gear 38 or the main case gear 40, respectively. The shift gear shaft 28 is supported by the ball bearing assembly 154, and the main case gear 44 is separated from the ball bearing assembly 154 by a spacer 660 which transfers the thrust load from the clutch hub 654 to the inner bearing race.

[0084] refer to Fig.18, an alternative arrangement of the input shaft 23 according to the fifth alternative embodiment has an alternative two-piece extension shaft 24a, 24b, a main shaft 26, a shift shaft 28 and thrust bearings 700, 702. The transmission 10 is capable of providing power throughput from a prime mover (not shown) interfaced with the clutch unit 22 to the input shaft 23, from the input shaft 23 to the two-piece extension shaft 24a, 24b, from the two-piece extension shaft 24a, 24b to the main shaft portion 26, from the main shaft portion 26 to the shift shaft portion 28, and from the shift shaft portion 28 to the output shaft assembly 30. The secondary extension shaft 24b is press-fitted or otherwise connected to the primary extension shaft 24a. The primary extension shaft 24a includes internal splines that are connected to the external splines 23a of the input shaft 23. As previously described herein, the front end of the primary extension shaft 24a is supported by the bearing assembly 150. The primary extension shaft 24a also includes external splines that connect to the internal splines of the clutch hub. The first sub-transmission gear 34 is loosely supported on the primary extension shaft 24a by needle bearings, and the second sub-transmission gear 36 is loosely supported on the primary extension shaft 24a by needle bearings 714. As previously described herein, the first sub-transmission gear 34 is disposed against the clutch hub and against the thrust washer. The second sub-transmission gear 36 is disposed against the thrust washer and against the shoulder 718 of the primary extension shaft 24a. The axial end of the primary extension shaft 24a includes a pocket 720 that receives a wave spring 722 disposed against the thrust washer 724. The first thrust bearing 700 has a plurality of cylindrical rollers 726 disposed against the thrust washer 724 and against the thrust washer 728. The thrust race 728 is supported on the secondary extension shaft 24b by a pair of needle bearings 732a, 732b. The third auxiliary transmission gear 38 is supported with radial clearance relative to the thrust race 728. The second thrust bearing 702 includes a plurality of cylindrical rollers 734 disposed against a thrust washer 736 disposed against the bearing race 728. The race 738 is disposed against the second thrust bearing 702 and includes a tapered rear surface disposed against a spherical washer 740. The spherical washer 740 is disposed against the end of the main shaft 26. A wave spring 742 is disposed in an end pocket 744 in the main shaft 26 and presses against the spherical washer 740.

[0085] The rear end of the secondary extension shaft 24b is supported by a needle bearing 748 in an aperture 746 of the shift gear shaft 28. The shift gear shaft 28 includes internal splines 750 that engage external splines 752 of the main shaft 26. Both main case gears 40 and 42 are located on the main shaft 26, and the main case gear 44 is located on a clutch hub 754. A second slip clutch 756 is supported on the clutch hub 754 and includes clutch teeth 756a, 756b for engaging corresponding clutch teeth 42a, 44a of the main case gears 42, 44, respectively. A third slip clutch 758 includes internal splines 758a that engage with external splines 752 of a clutch hub 759, and includes external clutch teeth 758b, 758c that can engage with clutch teeth 38a, 40a of the auxiliary transmission gear 38 or the main case gear 40, respectively. The shift gear shaft 28 is supported by the ball bearing assembly 154, and the main case gear 44 is separated from the ball bearing assembly 154 by a spacer 760 which transfers the thrust load from the clutch hub 754 to the inner bearing race.

[0086] The shaft and bearing architecture of the dual countershaft splitter type transmission provides robust gearbox alignment and compliant front splitter gear drive support. This architecture provides robustness against misalignment of the engine flywheel guide bearing relative to the transmission gearbox centerline. This architecture also provides robust torque / power sharing for the dual countershaft splitter type transmission, in addition to benefits for power take-off device drive and potential auxiliary hybridization.

[0087] For the purpose of illustration and description, the foregoing description of the embodiment has been provided. This is not intended to be exhaustive or to limit the present disclosure. The individual elements or features of a particular embodiment are generally not limited to the particular embodiment, but are interchangeable and can be used in selected embodiments where appropriate, even if the individual elements or features are not specifically shown or described. The individual elements or features can also be changed in many ways. Such changes should not be considered as departing from the present disclosure, and all such modifications are intended to be included within the scope of the present disclosure.

[0088] The terms used herein are only used to describe the purpose of specific example embodiments, and are not intended to be limiting. As used herein, unless the context clearly indicates otherwise, the singular forms "one", "a kind of" and "said" may be intended to include plural forms as well. The terms "comprise", "cover", "include" and "have" are all inclusive and therefore specify the existence of stated features, integers, steps, operations, elements and / or parts, but do not exclude the existence or addition of one or more other features, integers, steps, operations, elements, parts and / or their groups. The method steps, processes and operations described herein should not be understood as necessarily needing to be performed in the particular order discussed or shown, unless the particular order is specifically identified as an execution order. It should also be understood that additional or alternative steps may be adopted.

[0089] When an element or layer is referred to as being "on another element or layer," "engaged to," "connected to," or "coupled to" another element or layer, the element or layer may be directly on, engaged to, connected to, or coupled to another element or layer, or there may be intervening elements or layers. Conversely, when an element is referred to as being "directly on another element or layer," "directly engaged to," "directly connected to," or "directly coupled to" another element or layer, there may be no intervening elements or layers. Other words used to describe the relationship between elements should be interpreted in a similar manner (e.g., "between" versus "directly between," "adjacent" versus "directly adjacent," etc.). As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0090] For the purpose of illustration and description, the foregoing description of the embodiment has been provided. This is not intended to be exhaustive or to limit the present disclosure. The individual elements or features of a particular embodiment are generally not limited to the particular embodiment, but are interchangeable and can be used in selected embodiments where appropriate, even if the individual elements or features are not specifically shown or described. The individual elements or features can also be changed in many ways. Such changes should not be considered as departing from the present disclosure, and all such modifications are intended to be included within the scope of the present disclosure.

Claims

1. A transmission, comprising: Input shaft; a two-piece extension shaft having a primary extension shaft portion and a separate secondary extension shaft portion drivingly connected to the primary extension shaft portion, the primary extension shaft portion drivingly connected to the input shaft; a first auxiliary transmission gear and a second auxiliary transmission gear and a third auxiliary transmission gear, the first auxiliary transmission gear and the second auxiliary transmission gear being selectively coupleable to the primary extended shaft portion, the third auxiliary transmission gear being supported on a thrust race rotatably supported on the secondary extended shaft portion; a main shaft rotatably supported on the secondary extended shaft portion and including a plurality of main case gears selectively coupleable to the main shaft; a shift shaft drivingly coupled to the main shaft, the shift shaft providing input to a planetary gear assembly; at least one countershaft having a plurality of gears disposed thereon and meshingly engaged with corresponding gears of the plurality of auxiliary transmission gears and the plurality of main section gears; as well as A PTO drive gear is connected to the primary extension shaft portion for rotation.

2. The transmission according to claim 1, further comprising: a first thrust bearing disposed between the primary extension shaft portion and the thrust race; and a second thrust bearing disposed between the thrust race and the main shaft.

3. The transmission according to claim 2, further comprising: A thrust washer is disposed between the first thrust bearing and an end of the primary extension shaft portion.

4. The transmission of claim 2, wherein the first thrust bearing is disposed directly against the thrust race.

5. The transmission of claim 2, wherein the second thrust bearing is disposed directly against the thrust race.

6. The transmission according to claim 2, further comprising: A bearing race is disposed between the second thrust bearing and the main shaft.

7. The transmission of claim 2, further comprising: A thrust washer is disposed between the thrust race and the second thrust bearing.

8. The transmission of claim 2, further comprising: A thrust washer is disposed between the first thrust bearing and the thrust race.

9. The transmission of claim 1, wherein the plurality of main case gears includes three main case gears, and wherein the planetary gear assembly provides two gear speeds such that the transmission has a 3x3x2 architecture.

10. The transmission of claim 2, further comprising: A clutch hub rotatably connects the main shaft to the shift shaft.

11. The transmission of claim 2, wherein the main shaft includes external splines drivingly connected to internal splines of the shift shaft.

12. A transmission, comprising: Input shaft; a one-piece extension shaft drivingly connected to the input shaft; a first auxiliary transmission gear and a second auxiliary transmission gear and a third auxiliary transmission gear, the first auxiliary transmission gear and the second auxiliary transmission gear being selectively coupleable to the extension shaft, the third auxiliary transmission gear being supported on a thrust race, the thrust race being rotatably supported on the extension shaft; a main shaft rotatably supported on the extension shaft and including a plurality of main case gears selectively coupleable to the main shaft; a shift shaft drivingly coupled to the main shaft, the shift shaft providing input to a planetary gear assembly; at least one countershaft having a plurality of gears disposed thereon and meshingly engaged with corresponding gears of the plurality of auxiliary transmission gears and the plurality of main section gears; as well as a first thrust bearing disposed between the extension shaft and the thrust race, the first thrust bearing being disposed directly against the thrust race; and a second thrust bearing disposed between the thrust race and the main shaft.

13. The transmission of claim 12, further comprising: A thrust washer is disposed between the first thrust bearing and an end of the extension shaft.

14. The transmission of claim 13, further comprising: A spring member is disposed between the thrust washer and the extension shaft.

Images