Improved architecture for powertrains for multi-power source work vehicles

Abstract

A powertrain for a work vehicle includes an engine and a transmission. The transmission includes a continuously variable power source (CVP) and a variator operably connected to the engine and the CVP. The variator includes a first planetary gear set and a second planetary gear set. A shift shaft has a shift shaft output gear fixed thereto, and an output shaft has an output shaft gear driven by the shift shaft output gear. A first mode select clutch has a first input member engaged with an output gear of the first planetary gear set and a first output member connected to the shift shaft, and a second mode select clutch has a second input member engaged with an output gear of the second planetary gear set and a second output member connected to the shift shaft. The first and second mode select clutches are selectively operable to connect the first input member with the first output member or the second input member with the second output member, and thereby transfer power from the variator to the output shaft.

Description

Technical Field

[0001] This disclosure generally relates to powertrains for work vehicles, including powertrains for operating work vehicles used in agriculture, forestry, construction and other applications. Background Technology

[0002] Work vehicles can utilize both a conventional engine (e.g., an internal combustion engine) and one or more continuously variable power sources (“CVPs”) (e.g., electric motors / generators or hydraulic motors / pumps, etc.) to provide useful power for traction and work operations. Such power systems can operate in various modes, providing pure engine-mechanical power, non-mechanical power, or pure CVP power, or a combination of mechanical and non-mechanical “separate path” power. In various such power systems, one or more CVPs can operate in series or parallel to deliver or utilize power. For example, a CVP can power or be integrated into a continuously variable transmission (“CVT”), which can also receive engine power and output direct mechanical power, CVP power, or separate path power to ground engagement components (e.g., wheels or tracks) or drive axles to drive the vehicle for traction. Summary of the Invention

[0003] This disclosure provides a powertrain for a work vehicle, the powertrain including an engine and a transmission. The transmission includes: a continuously variable power source (CVP); a gearbox; a shift shaft having a shift shaft output gear fixed to the shift shaft; and an output shaft having an output shaft gear driven by the shift shaft output gear. The gearbox is operably connected to the engine and the CVP, and the gearbox includes a first planetary gear set and a second planetary gear set. The transmission also includes a first mode selection clutch and a second mode selection clutch, the first mode selection clutch having a first input component engaging with an output gear of the first planetary gear set and a first output component connected to the shift shaft, and the second mode selection clutch having a second input component engaging with an output gear of the second planetary gear set and a second output component connected to the shift shaft. The first mode selection clutch and the second mode selection clutch are selectively operable to engage the first input component with the first output component or the second input component with the second output component, thereby transmitting power from the gearbox to the output shaft.

[0004] This disclosure also provides a transmission for a work vehicle with an engine. The transmission includes a housing, and the housing contains: a continuously variable power source (CVP); a transmission operably connected to the engine and the CVP; a shift shaft having a shift shaft output gear fixed to the shift shaft; and an output shaft driven by the shift shaft output gear. The transmission includes a first planetary gear set and a second planetary gear set. The housing also contains a first mode selection clutch and a second mode selection clutch, the first mode selection clutch having a first input component engaging with the output gear of the first planetary gear set and a first output component configured to drive the shift shaft, and the second mode selection clutch having a second input component engaging with the output gear of the second planetary gear set and a second output component configured to drive the shift shaft. The first mode selection clutch and the second mode selection clutch are selectively operable to connect the first input component to the first output component or the second input component to the second output component, thereby transmitting power from the transmission to the output shaft.

[0005] In some embodiments, the first planetary gear set is a low-speed planetary gear set, and the second planetary gear set is a high-speed planetary gear set. In some embodiments, the output gear of the first planetary gear set is the planet carrier of the first planetary gear set. In other embodiments, the output gear of the second planetary gear set is the ring gear of the second planetary gear set.

[0006] In some embodiments, the transmission further includes a clutch shaft and a third mode selection clutch, wherein a third input component of the third mode selection clutch meshes with both an output gear fixed to the output shaft of the CVP and an input gear of the first planetary gear set, and a third output component of the third mode selection clutch is connected to the clutch shaft. In some embodiments, the transmission operates in a first mode, a second mode, and a third mode, wherein in the first mode, the third mode selection clutch is engaged to transmit power from the CVP to both the clutch shaft and the transmission; in the second mode, the first mode selection clutch is engaged and the third mode selection clutch is disengaged; and in the third mode, the second mode selection clutch is engaged. In other embodiments, the transmission further includes a clutch shaft output gear fixed to the clutch shaft, and the clutch shaft output gear is operable to transmit power to the transmission. In still other embodiments, the transmission further includes a reverse clutch, wherein the input component of the reverse clutch is driven by the output shaft of the engine, and the output component of the reverse clutch is connected to the clutch shaft.

[0007] In some embodiments, the powertrain or the work vehicle further includes a forward clutch, wherein the input component of the forward clutch is fixed to the output shaft of the engine, and the output component of the forward clutch is configured to transmit power directly from the engine to the transmission when the input component of the forward clutch is engaged with the output component of the forward clutch.

[0008] In some embodiments, when the output shaft is driven in a first direction, the CVP operates in both the first direction and the opposite second direction.

[0009] Details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features and advantages will become apparent from the specification, drawings, and claims. Attached Figure Description

[0010] Figure 1 This is an exemplary work vehicle in the form of a wheeled loader that can incorporate the powertrain of this disclosure;

[0011] Figure 2 It is used for Figure 1 A schematic diagram of an exemplary architecture of a multi-power source powertrain for an exemplary work vehicle;

[0012] Figure 2A It is shown Figure 2 A schematic diagram of the power transmission path in the first forward or reverse operating mode of the exemplary architecture.

[0013] Figure 2B It is shown Figure 2 A schematic diagram of the power transmission path in the second forward operating mode of the exemplary architecture;

[0014] Figure 2C It is shown Figure 2 A schematic diagram of the power transmission path in the third forward operating mode of the exemplary architecture;

[0015] Figure 2D It is shown Figure 2 A schematic diagram of the power transmission path in the second reverse operation mode of the exemplary architecture;

[0016] Figure 2E It is shown Figure 2 A schematic diagram of the power transmission path in the third reverse operation mode of the example architecture;

[0017] Figure 3 It is shown Figure 1 The ground speed of the operating vehicle and Figure 1A graph showing the relationship between the outputs of the continuously variable power sources in the powertrain; and

[0018] Figure 4 It is shown Figure 1 A graph showing the relationship between the ground speed of the operating vehicle and the rim tension.

[0019] In the various figures, the same reference numerals denote the same elements. Detailed Implementation

[0020] The following describes one or more exemplary embodiments of the disclosed powertrain for a work vehicle, as shown in the accompanying figures of the accompanying drawings, which are briefly described above. Various modifications to the exemplary embodiments will be conceived by those skilled in the art. The discussion herein focuses on powertrains for work vehicles (e.g., wheel loaders), but the powertrains disclosed herein can be used in other contexts, including other work vehicle platforms in agriculture, construction, forestry, mining, and other industries.

[0021] In the following discussion, various exemplary configurations of shafts, gears, clutches, and other power transmission elements are described. It should be understood that various alternative configurations are possible within the spirit of this disclosure. For example, various configurations may utilize multiple shafts instead of a single shaft (or a single shaft instead of multiple shafts), one or more inertial gears may be inserted between various shafts or gears to transmit rotational power, and so on.

[0022] As used herein, in some embodiments, gears and / or other components of the powertrain are disclosed as meshing with each other, which may mean that two or more components are actually physically meshed with each other. However, it should be understood that describing a first component as meshing with a second component may also encompass the first component being configured to drive or be driven by the second component.

[0023] As used herein, "direct" or "directly" can be used to indicate the transmission of power between two system components without the need for an intermediate conversion of power to another form. For example, if power is transmitted via multiple shafts, clutches, and gears (e.g., various spur gears, bevel gears, accumulator gears, or other gears) without being converted to a different form by a CVP (e.g., without being converted to electrical or hydraulic power by a generator or hydraulic pump), then power can be considered to be transmitted "directly" from the engine to the output component. In some configurations, the fluid transmission of rotational power via a torque converter can also be considered "direct."

[0024] In contrast, if some portion of the power is converted to another form during transmission, the power may not be considered to be transferred "directly" between the two system components. For example, if a portion of the engine's power is converted to a different form by a CVP, even if that portion is later (e.g., via another CVP) converted back to rotational power and then recombined with unconverted engine power (e.g., via a planetary gear set or other accumulating components), the power may not be considered to be transferred "directly" between the engine and the output components. Overview

[0025] The work vehicle includes a chassis, a powertrain with a power-generating engine and transmission, a driveline, and multiple ground-connecting components (e.g., wheels, tracks, etc.). The driveline includes a drive shaft, one or more axles connected to the ground-connecting components, and one or more differentials connecting the drive shaft to corresponding axles among the one or more axles. The driveline transmits power generated by the engine to its output shaft connected to the drive shaft, thereby causing rotation of the drive shaft, and this rotation causes the one or more axles to rotate subsequently via the differentials. The driveline can operate in various modes, and each mode provides the combination of torque and rotational speed necessary to meet the operational requirements of the work vehicle.

[0026] The drivetrain may include one or more continuously variable power sources (CVPs), such as electric motors, gears, clutches, shafts, and other components, to transmit power generated by the engine to the output shaft. Mechanical power from the engine can be converted into electricity to drive the CVPs. The controller can operate the drivetrain in different modes to drive the output shaft (and thus the work vehicle) using power supplied solely by the CVPs, or a combination of mechanical power supplied directly from the engine without conversion to electricity and power from the CVPs.

[0027] Electric motors can be used individually to provide sufficient torque to support CVP operation of the work vehicle in certain modes. Furthermore, the controller can dynamically adjust the speed of such electric motors and selectively operate the motor in a first direction or a second direction opposite to the first. For example, the first direction can be associated with forward movement of the work vehicle, and the second direction can be associated with reverse movement of the work vehicle. Operating the drivetrain in pure CVP mode can be particularly suitable for situations where the work vehicle is operated with rapidly changing speeds and directions, such as when operating a wheel loader to move piles of materials at a work site. For example, when operating the drivetrain in pure CVP mode before needing to shift to a split-path operation mode, using a suitable electric motor can result in a significant increase in the operating speed range because the output speed, torque, and direction of the output shaft can be electronically changed by controlling the output speed and direction of the CVP. The increased operating speed range leads to smoother operation of the work vehicle and greater comfort for the operator.

[0028] Furthermore, even in those modes where the transmission uses both direct mechanical power from the engine and power from the CVP to drive the output shaft (i.e., in the split-path mode), the speed and direction of the CVP output can be electronically changed to provide an increased speed range, and a lower gear ratio between the CVP and the output shaft can be used even at medium speeds.

[0029] Those skilled in the art will understand that the reflective inertia of a CVP varies with the square of the gear ratio between the CVP and the output shaft, and this inertia must be overcome by the torque generated by the CVP. Using a CVP that incorporates existing electric motor technology with high torque density allows for reduced gear reduction between the output shaft of the transmission and the CVP, thereby reducing reflective inertia and consequently leading to improved torque transmission to the output shaft and smoother transitions between modes.

[0030] In one embodiment, the transmission includes (in addition to the one or more CVPs and output shafts) a clutch shaft, a gearbox, a shift shaft, clutches, and various gears. Furthermore, as discussed in more detail below, multiple clutches are connected to a common shaft or otherwise configured to drive a common shaft, resulting in a reduction in the number of components (e.g., shafts and gears) required to operate the transmission. This reduction in components leads at least to a corresponding reduction in the cost of the transmission and the housing / encapsulation requirements of the transmission.

[0031] The transmission includes a first input terminal and a second input terminal. When the work vehicle is operated, mechanical power generated by the engine or CVP can be selectively transmitted to the first input terminal, and at least a first portion of the power generated by the CVP is transmitted to the second input terminal of the transmission. A first mode selection clutch and a reverse clutch are connected to a clutch shaft, and when one of these clutches is engaged, the clutch shaft is driven using a second portion of the power generated by the CVP or mechanical power directly from the engine, respectively. In some embodiments, the first mode selection clutch and the reverse clutch include a dual clutch connected to a common clutch shaft or otherwise configured to drive a common clutch shaft. When the first mode selection clutch is engaged, power at the output shaft of the second CVP is transmitted to both the clutch shaft and the second input terminal of the transmission. When the first mode selection clutch is disengaged, power at the output shaft of the second CVP is transmitted only to the second input terminal of the transmission.

[0032] A forward clutch is mounted on the engine output shaft. When the first mode selection clutch is disengaged, one of the forward and reverse clutches can be selectively engaged to directly transmit mechanical power generated by the engine to the first input of the transmission. Specifically, when the forward clutch is engaged and the reverse clutch is disengaged, the engine output shaft mechanically drives the first input of the transmission. When the forward clutch is disengaged and the reverse clutch is engaged, the engine output shaft mechanically drives the clutch shaft, which in turn drives the first input of the transmission. Furthermore, one or more gears are arranged in a mechanical path between the engine output shaft and the first input of the transmission such that the direction of rotation of the first input of the transmission when the forward clutch is engaged is opposite to the direction of rotation when the reverse clutch is engaged.

[0033] The transmission includes a low-speed planetary gear set and a high-speed planetary gear set. The power generated at the output ends of the low-speed and high-speed planetary gear sets reflects the sum of the power supplied to the first and second input ends of the transmission. Specifically, the gear ratio of the low-speed planetary gear set is selected such that its output end rotates at high torque and low speed, and the gear ratio of the high-speed planetary gear set is selected such that its output end rotates at lower torque and higher speed. In some embodiments, the power supplied to the first input end of the transmission (i.e., power from the second CVP or power directly from the engine) drives the planet carrier of the high-speed planetary gear set, and the planet gears of the high-speed planetary gear set drive the ring gear of the low-speed planetary gear set. Furthermore, the power supplied to the second input end of the transmission (i.e., power from the second CVP) drives the sun gear of both the low-speed and high-speed planetary gear sets.

[0034] The second and third mode selection clutches are connected to the shift shaft and can be selectively engaged to transmit power from either the low-speed or high-speed planetary gear set of the transmission to the shift shaft, which in turn drives the output shaft of the transmission. In some embodiments, engaging the second mode selection clutch transmits power from the planet carrier of the low-speed planetary gear set to the shift shaft, and engaging the third mode selection clutch transmits power from the ring gear of the high-speed planetary gear set to the shift shaft. In some embodiments, the second and third mode selection clutches may comprise a dual clutch connected to a common shift shaft or otherwise configured to drive a common shift shaft.

[0035] When the reverse clutch is engaged (and the first mode selection clutch and the forward clutch are disengaged), mechanical power at the engine's output shaft is directly transmitted to and drives the clutch shaft. The clutch shaft output gear is mechanically connected to and drives the transmission's second input in a manner similar to when the forward mode selection clutch is engaged (except in the opposite direction).

[0036] When the first and second mode selection clutches are engaged (and the third mode selection clutch is disengaged), the transmission output shaft is driven solely by the second CVP. Furthermore, when the powertrain output shaft is driven solely by the second CVP, neither the forward nor reverse clutches are engaged, as the direction of the second CVP can be electronically changed. Therefore, the transmission can be operated to drive the work vehicle in both forward and reverse directions and at a wider speed range before a gear shift is required.

[0037] Furthermore, connecting multiple clutches to each of the clutch shaft and shift shaft, and connecting the forward clutch to the engine output shaft, simplifies the gear train architecture of the transmission. This simplified gear train results in a reduction in the number of transmission components and its housing / encapsulation requirements, which can lead to cost and operational improvements.

[0038] The controller monitors the power requirements and operating conditions of the work vehicle, and in response, operates components of the powertrain, including the engine, one or more CVPs, forward and reverse clutches, and first, second and third mode selection clutches, to generate sufficient power to meet the demand. Exemplary multi-mode powertrain

[0039] refer to Figure 1The work vehicle 100 may include a controller 102, a powertrain 106, and one or more sensors 110 disposed on the chassis 112. The controller 102 operates the powertrain 106 in response to signals and / or data from the multiple sensors 110 to ensure consistent and smooth operation of the work vehicle 100. Figure 1 The work vehicle 100 is generally described as a wheeled loader, but the work vehicle 100 may be another configuration used in agriculture, construction, forestry, mining and other industries. It should also be understood that the powertrain 106 of the work vehicle 100 described herein may also be used in non-work vehicles and even in non-vehicle applications (e.g., stationary power installations).

[0040] Also refer to Figure 2 The powertrain 106 includes: one or more power sources, such as engine 114 (e.g., an internal combustion engine) and one or more continuously variable power sources, such as a first continuously variable power source (CVP) 116a and a second continuously variable power source (CVP) 116b of transmission 118 (e.g., one or more electric motors); and various batteries and power transmission elements. Components of transmission 118 are housed in transmission housing 119 and are operated to transmit power via output shaft 122 from power sources 114, 116a, 116b to one or more ground engagement members 120. Ground engagement members 120 may be, for example, wheels or tracks for the travel and operation of work vehicle 100. Transmission 118 may also supply power to drive other vehicle systems, components, or implements (not shown). Transmission 118 may include various gears, shafts, clutches, and other power transmission elements that can operate within a range representing selected output speeds and / or torques. As described herein, controller 102 monitors signals and / or data supplied by one or more sensors 110 that indicate the operating status and needs of the work vehicle 100, and in response, operates the drive unit 118 in different modes according to such operating status and needs.

[0041] Controller 102 can be configured as one or more computing devices with associated processor devices and memory architectures. Therefore, controller 102 can be configured to execute instructions stored in memory to implement various computing and control functions relating to vehicle 100 as described herein. Controller 102 may include, for example, a computer, a device using one or more application-specific integrated circuits (ASICs) and / or field-programmable gate arrays (FPGAs), and / or combinations thereof. The computing devices may be monolithic or may be multiple distributed computing devices, and one or more such computing devices may be locally mounted on or off the work vehicle 100. Each computing device may communicate with another computing device via one or more networks such as a local area network (LAN), a control area network (CAN), a cellular network, a wide area network (WAN) such as the Internet. Furthermore, controller 102 can communicate electronically or hydraulically with various actuators, sensors, and other devices within (or outside) the work vehicle 100.

[0042] In some embodiments, controller 102 may be configured to receive input commands and interact with an operator via a human-machine interface or operator interface (not shown), including typical steering, acceleration, speed, transmission, and wheel braking control, as well as other suitable controls. The human-machine interface may be configured in various ways and may include one or more joysticks, various switches or levers, one or more buttons, a touchscreen interface that may be located on a display, a keyboard, a speaker, a microphone associated with a voice recognition system, or various other human-machine interface devices. Controller 102 may receive input from one or more sensors 110 (generally represented by sensor 110) associated with various systems and components of the work vehicle 100, and generate appropriate commands for the components of the powertrain 106 based on these inputs.

[0043] Sensor 110 may include kinematic sensors, such as one or more orientation sensors and / or one or more ground speed sensors, that collect information associated with the position and / or movement of the work vehicle 100. Additional sensors (or otherwise, sources or data) may provide or include sources of powertrain data, including data sufficient to determine the current or intended mode of transmission 118, information associated with the position of one or more transmission clutches, and torque and / or speed information associated with the engine 114, the first CVP 116a and the second CVP 116b, and / or the components of transmission 118. For example, sensor 110 may collect information associated with the current engine speed, either directly or derived from other parameters.

[0044] As described above, the powertrain 106 may include one or more power sources and transmissions 118, such as an engine 114, which may be an internal combustion engine of various known configurations. Furthermore, the transmission 118 may include one or more CVPs 116a, 116b and an inverter 117. The inverter 117 converts alternating current to direct current, which is supplied from the controller 102 for use by the CVPs 116a, or from one CVP 116a for use by another CVP 116b. The first CVP 116a and the second CVP 116b may be connected to each other via conduit 116c. In some embodiments, conduit 116c may connect the first CVP 116a to the inverter 117 and the inverter to the second CVP 116b.

[0045] The transmission 118 transmits power from one or more power sources 114, 116a, 116b to an output shaft 122, which is configured to supply power to a drivetrain (not shown) and thereby drive the ground engagement member 120. As described below, the transmission 118 includes multiple gear drives, clutches, and control components to appropriately drive the output shaft 122 of the transmission 118 (and thus the powertrain 106) at different speeds, torques, and directions as needed, thereby meeting the operational requirements of the work vehicle 100.

[0046] In one embodiment, the power generated by engine 114 can drive engine output shaft 130 and gear 132 fixed to engine output shaft 130. Gear 132 meshes with gear 134 fixed to power output shaft 136 and with gear 138 fixed to input shaft 140 of first CVP 116a. Thus, when engine 114 drives engine output shaft 130, gear 132 transmits power from engine 114 to gear 134 to drive both power output shaft 136 and gear 138. Gear 138 transmits power to input shaft 140 of first CVP 116a. First CVP 116a converts the power supplied to input shaft 140 into electricity and transmits this electricity via conduit 116c to second CVP 116b. In some embodiments, power output shaft 136 supplies power to one or more implements and / or accessories (not shown) of work vehicle 100. Furthermore, the power output shaft 136 can drive one or more inert gears (not shown) disposed between gears 132 and gear 138, which are obvious to those skilled in the art.

[0047] As described in more detail below, controller 102 operates transmission 118 as needed to transmit mechanical power generated by engine 114 and / or second CVP 116b to output shaft 122 of transmission 118 to support operation of work vehicle 100. Transmission includes clutch shaft 150, gearbox 152, and shift shaft 154. Gearbox 152 includes low-speed planetary gear set 156, high-speed planetary gear set 158, first gearbox shaft 160, and second gearbox shaft 162, the second gearbox shaft 162 being concentrically supported on the first gearbox shaft 160 by, for example, one or more bearings.

[0048] The low-speed planetary gear set 156 includes: a ring gear 164, a sun gear 166 fixed to and driven by a second transmission shaft 162, one or more planet gears 168 meshing with both the ring gear 164 and the sun gear 166, and a planet carrier 170 connected to the one or more planet gears 168. The high-speed planetary gear set 158 ​​includes: a ring gear 172, a sun gear 174 fixed to and driven by the second transmission shaft 162, and one or more planet gears 176 meshing with both the ring gear 172 and the planet carrier 178. The planet carrier 178 is connected to and driven by a first transmission input shaft 160. Furthermore, one or more planet gears 176 of the high-speed planetary gear set 158 ​​drive the ring gear 164 of the low-speed planetary gear set 156. The low-speed planetary gear set 156 and the high-speed planetary gear set 158 ​​of the transmission 152 are configured such that, when a specific amount of combined power is supplied to the first transmission shaft 160 and the second transmission shaft 162, the planet carrier 170 of the low-speed planetary gear set 156 is driven at low speed and high torque, and the ring gear 172 of the high-speed planetary gear set 158 ​​is driven at high speed and low torque. This combined power can be supplied solely by the second CVP 116b, or it can be a combination of power directly supplied by the engine 114 and the second CVP 116b.

[0049] The controller 102 operates the components of the transmission 118 according to several selectable modes to deliver power solely from the second CVP 116b to the output shaft 122 of the transmission 118, or to deliver power from both the second CVP 116b and the engine 114 to the output shaft 122 of the transmission 118. In a first mode suitable for operation, sufficient torque must be supplied to the output shaft 122, for example, for transporting the work vehicle 100 from a standstill, transporting the vehicle at low speed to carry a load, or rapidly changing between forward and reverse directions of travel. In the first mode, the power generated solely by the second CVP 116b is transmitted to both the first transmission shaft 160 and the second transmission shaft 162, and thus to the output shaft 122. In this mode, mechanical power from the engine 114 is prevented from being directly transmitted to the output shaft 122. In the second mode, used when the work vehicle 100 is moving, such as when pulling a load at a moderate speed or on terrain requiring a balance of torque and speed, engine 114 supplies mechanical power directly to the first transmission shaft 160, and the second CVP 116b supplies power to the second transmission shaft 162. The sum of the power supplied by engine 114 and the power supplied by the second CVP 116b is transmitted from the output end of the low-speed planetary gear set 156 of transmission 152 to drive the output shaft 122. In the third mode, used when the work vehicle 100 is in motion and speed is required more than torque, power is supplied to the first transmission shaft 160 and the second transmission shaft 162, as in the second mode; however, the sum of the power generated by engine 114 and the power generated by the second CVP 116b is transmitted from the output end of the high-speed planetary gear set 158 ​​to drive the output shaft 122. Furthermore, for each of the first, second, and third modes in which the controller 102 operates the powertrain 106, the controller 102 can also select that the output shaft 122 rotates in the direction associated with the forward movement of the work vehicle 100 or in the opposite direction associated with the reverse movement of the work vehicle 100.

[0050] In some embodiments, the powertrain 106 includes a first mode selection clutch 200, a second mode selection clutch 202, a third mode selection clutch 204, a forward clutch 206, and a reverse clutch 208. Each clutch 200, 202, 204, 206, and 208 can be a wet clutch, a dry clutch, a dog collar clutch, a brake, a synchronizer, etc. Each clutch 200, 202, 204, 206, and 208 includes input components 200a, 202a, 204a, 206a, and 208a, and output components 200b, 202b, 204b, 206b, and 208b, respectively. The controller 102 can operate each clutch 200, 202, 204, 206 and 208 to put it into an engaged or disengaged state. In the engaged state, the power supplied at the input part of the clutch is transmitted to the output part of the clutch. In the disengaged state, the transmission of power at the input part of the clutch is prevented from being transmitted to the output part of the clutch.

[0051] In one embodiment, the input component 200a of the first mode selection clutch 200 engages with an idler gear 212, which in turn engages with a drive gear 214 fixed to the output shaft 216 of the second CVP 116b. Furthermore, the input component 200a also engages with a gear 218 fixed to the second transmission shaft 162. Additionally, the output component 200b of the first mode selection clutch 200 is connected to the clutch shaft 150 (i.e., engaged with a gear fixed to the clutch shaft 150, or otherwise configured to drive the clutch shaft 150). Therefore, when the first mode selection clutch 200 is disengaged, the power generated by the second CVP 116b is transmitted to the second transmission shaft 162 solely from the output shaft 216 of the second CVP 116b via the drive gear 214, the idler gear 212, the input component 200a of the first mode selection clutch 200, and the gear 218. When the first mode selection clutch 200 is engaged, power from the second CVP 116b is transmitted from the output shaft 216 of the second CVP 116b to the second transmission shaft 162 and simultaneously to the clutch shaft 150 via the drive gear 214, the idler gear 212, the input component 200a of the first mode selection clutch 200, and the output component 200b of the first mode selection clutch 200.

[0052] The input component 208a of the reverse clutch 208 engages with a gear 222 fixed to the engine output shaft 130, and the output component 208b of the reverse clutch 208 is connected to the clutch shaft 150. When the reverse clutch 208 is engaged, mechanical power generated by the engine 114 is transmitted from the engine output shaft 130 to the clutch shaft 150 via the gear 222, the input component 208a, and the output component 208b. The input component 208a and the gear 222 of the reverse clutch 208 are configured to rotate in opposite directions, for example, by meshing with each other without any idler gears or an even number of idler gears between them. Therefore, when the reverse clutch 208 is engaged, the engine output shaft 130 and the clutch shaft 150 rotate in opposite directions.

[0053] The clutch shaft output gear 224 is fixed to the clutch shaft 150 and meshes with the gear 226 fixed to the first transmission shaft 160, such that when the first mode selection clutch 200 or the reverse clutch 208 is engaged, the power from the clutch shaft 150 drives the first transmission shaft 160. Furthermore, because the output components 200b and 208b of both the first mode selection clutch 200 and the reverse clutch 208 drive the clutch shaft 150 respectively, the controller 102 can at any given time de-engage either the first mode selection clutch 200 or the reverse clutch 208, or have only one of them engaged.

[0054] The input component 206a of the forward clutch 206 is connected to the engine output shaft 130, and the output component 206b of the forward clutch 206 is connected to the first transmission shaft 160. Therefore, power generated by the engine 114 is directly transmitted to the first transmission shaft 160 via the engine output shaft 130, input component 206a, and output component 206b. Furthermore, because both the output gear 224 of the clutch shaft (driven when the first mode selection clutch 200 or the reverse clutch 208 is engaged) and the output component 206b of the forward clutch 206 drive the gear 226, the controller 102 either does not engage the first mode selection clutch 200, the forward mode clutch 206, or the reverse clutch 208 at any given time, or engages only one of these clutches.

[0055] As discussed above, when the first mode selection clutch 200 is engaged and the forward clutch 206 and the reverse clutch 208 are disengaged, the power generated by the second CVP 116b can be supplied to both the first transmission shaft 160 and the second transmission shaft 162 simultaneously. Alternatively, when the first mode selection clutch 200 is disengaged and either the forward clutch 206 or the reverse clutch 208 is engaged, the power generated by the engine 114 can be directly supplied (i.e., without first being converted to electricity via the first CVP 116a) to the first transmission shaft 160, and the power generated by the second CVP 116b can be supplied to the second transmission shaft 162.

[0056] According to the operation of the second mode selection clutch 202 and the third mode selection clutch 204, power generated by the engine 114 and / or the second CVP 116b is transmitted from the transmission 152 to the output shaft 122 via the shift shaft 154. Specifically, the input component 202a of the second mode selection clutch 202 meshes with the planet carrier 170 of the low-speed planetary gear set 156 of the transmission 152. The output component 202b of the second mode selection clutch 202 is connected to the shift shaft 154. The input component 204a of the third mode selection clutch 204 meshes with the ring gear 172 of the high-speed planetary gear set 158, and the output component 204b of the second mode selection clutch 204 is connected to the shift shaft 154. The shift shaft output gear 230 is also connected to and driven by the shift shaft 154. The shift shaft output gear 230 meshes with or is configured to drive the gear 232, which is fixed to the output shaft 122 of the powertrain 106. Therefore, when the second mode selection clutch 202 or the third mode selection clutch 204 is engaged, power is selectively transmitted from the low-speed planetary gear set 156 or the high-speed planetary gear set 158 ​​to the shift shaft 154. Furthermore, because both the output component 202b of the second mode selection clutch 202 and the output component 204b of the third mode selection clutch 204 are configured to drive the shift shaft 154, the controller 102 can keep only one of the second mode selection clutch 202 or the third mode selection clutch 204 engaged at any given time.

[0057] Therefore, when the powertrain 106 is operated to transport the work vehicle 100 in the forward direction, the controller 102 operates the clutches 200, 202, 204, 206 and 208 to select the operating mode of the transmission 118, as shown in Table 1 below. Table 1

[0058] Figure 2AThe diagram illustrates the power transmission path when the controller 102 operates the transmission 118 in the first mode to drive the work vehicle 100 in the forward direction. Also referenced is... Figure 2A Line 250a shows the power transmission path between the output shaft 216 of the second CVP 116b and the input shaft 160 of the first transmission; line 250b shows the power transmission path between the output shaft 216 and the input shaft 162 of the second transmission; and line 250c shows the power transmission path between the planet carrier 170 of the low-speed planetary gear set 156 of the transmission 152 and the output shaft 122 of the transmission 118.

[0059] Figure 2B The diagram illustrates the power transmission path when the controller 102 operates the transmission 118 in the second mode to drive the work vehicle 100 in the forward direction. (Reference) Figure 2B Line 252 illustrates the power transmission from the output of engine 114 to the first transmission shaft 160. Lines 250a and 250c illustrate the power transmission between the second CVP 116b and the second transmission shaft 162, and the power transmission from the low-speed planetary gear set 156 to the output shaft 122.

[0060] Figure 2C The diagram illustrates the power transmission path when the controller 102 operates the transmission 118 in the third mode to drive the work vehicle 100 in the forward direction. (Reference) Figure 2C Lines 250a and 252 illustrate the power transmission from the second CVP 116b to the second transmission shaft and from the engine 114 to the first transmission shaft, respectively. Line 254 illustrates the power transmission from the ring gear 172 of the high-speed planetary gear set 158 ​​of the transmission 152 to the output shaft 122.

[0061] Table 2 shows how the controller 102 operates the clutches 200, 202, 204, 206 and 208 to select the operating mode of the transmission 118 when the powertrain 106 is operated to transport the work vehicle 100 in the reverse direction. Table 2

[0062] Note that when the transmission 118 is operated in the first mode, both the forward clutch 206 and the reverse clutch 208 are disengaged. In the first mode, the output shaft 122 of the transmission 118 is driven solely by the power generated by the second CVP 116b. This is because the controller 102 electronically controls the direction of the output shaft 216 of the second CVP 116b according to the transport direction and power requirements of the work vehicle 100. Therefore, when the transmission 118 is operated in the first mode to transport the work vehicle in the reverse direction, the power transmission from the second CVP 116b to the output shaft is... Figure 2A The power transmission shown is the same.

[0063] Figure 2D The diagram illustrates the power transmission path from engine 114 and second CVP 116b to output shaft 122 when controller 102 operates transmission 118 in the second mode to drive work vehicle 100 in the reverse direction. (Reference) Figure 2D Line 256 shows the power transmission path from engine 114, reverse clutch 208, clutch shaft 150, and first transmission shaft 160. Lines 250a and 250c show the power transmission path from second CVP 116b to second transmission shaft 162, and from low-speed planetary gear set 156 to output shaft 122.

[0064] Figure 2E The diagram illustrates the power transmission path from engine 114 and second CVP 116b to output shaft 122 when controller 102 operates transmission 118 in the third mode to drive work vehicle 100 in the reverse direction. Reference Figure 2E Line 256 shows the power transmission path from engine 114 to first transmission shaft 160, line 250 shows the power transmission path from second CVP 116b to second transmission shaft 160, and line 254 shows the power transmission path from high-speed planetary gear set 158 ​​to output shaft 122.

[0065] In some embodiments, when the powertrain 106 is being operated to supply the operational requirements of the work vehicle 100, the controller 102 may electronically adjust the speed of the second CVP 116b. Figure 3 This is a graph showing how the speed of the second CVP 116b can change as the work vehicle 100 is transported, in one embodiment of the powertrain 106. (See reference) Figure 2 and Figure 3The horizontal axis 300 represents the transport speed of the work vehicle 100. The positive portion 300a of the horizontal axis 300 represents the forward movement of the work vehicle 100, and the negative portion 300b of the horizontal axis 300 represents the reverse movement of the work vehicle 100. The vertical axis 302 represents the rotational speed of the output shaft 216 of the second CVP 116b, wherein the positive portion 302a of the vertical axis 302 represents the rotation of the output shaft 216 along a first direction, and the negative portion 302b of the vertical axis 302 represents the rotation of the output shaft 216 along a second direction opposite to the first direction. Note that the engine 114 is in... Figure 3 The curves shown indicate that the operation is performed at a constant speed. In some embodiments, when the work vehicle 100 moves in the forward direction, the first direction of the output shaft 216 of the second CVP 116b may be the same as the rotation direction of the engine output shaft 130, and when the work vehicle 100 moves in the reverse direction, the second direction of the output shaft 216 may be the same as the rotation direction of the engine output shaft 130.

[0066] Line 304 illustrates the relationship between the rotational speed of the output shaft 216 of the second CVP 116b and the ground speed of the work vehicle 100 when the controller 102 operates the powertrain 106 in the first mode. As discussed above, the work vehicle 100 is transported using power solely from the second CVP 116b, and the direction and speed of the work vehicle 100 are determined by the rotational direction and speed of the output shaft 216 of the second CVP 116b without requiring mode or gear changes. This results in smoother operation of the work vehicle 100 at low speeds and when the transport direction of the work vehicle 100 frequently changes.

[0067] Line 306 shows the relationship between the rotational speed of the output shaft 216 and the forward speed of the work vehicle 100 when the forward clutch 206 is engaged and the powertrain 106 is operated in the second mode. Line 308 shows the relationship between the rotational speed of the output shaft 216 and the forward speed of the work vehicle 100 when the forward clutch 206 is engaged and the powertrain 106 is operated in the third mode.

[0068] As shown in line 306, although the work vehicle 100 is transporting in the forward direction, the controller 102 operates the second CVP 116b such that when the work vehicle 100 is moving forward at a rate between the rates associated with points A and B, the output shaft 216 rotates in the first direction, and when the work vehicle 100 is still moving forward at a rate between the rates associated with points B and C, the output shaft 216 rotates in the second direction (opposite to the first direction). The controller 102 reverses the rotation direction of the output shaft 216 of the second CVP 116b to compensate for the forward power transmitted directly from the engine 114 to the transmission 152. Operating the second CVP 116b in this way extends the rate range in which the work vehicle 100 can operate in the second mode (i.e., without the need for gear changes). Furthermore, as shown in line 308, after the controller 102 has transitioned the operation of the powertrain 106 from the second mode to the third mode, the rotational speed of the output shaft 216 in the second direction decreases as the forward rate of the work vehicle 100 increases, and finally, when the work vehicle 100 is moving forward at a greater rate than that associated with point D, both the output shafts 216 of the engine 114 and the second CVP 116b are driven in the same (first) direction, again increasing the range of speeds that the work vehicle 100 can operate without gear shifting. Lines 310 and 312 show the relationship between the rotational speed of the output shaft 216 and the reverse rate of the work vehicle 100 when the reverse clutch 208 is engaged and the controller 102 operates the powertrain 106 in the second mode (line 310) and the third mode (line 312).

[0069] Figure 4 This is a graph illustrating how the rim pull (i.e., the amount of traction supplied to the ground engagement member 120) of an embodiment of the work vehicle 100 varies with the forward speed of the work vehicle 100, represented on the vertical axis 314. Curve 318 shows the relationship between the rim pull and forward speed of the work vehicle 100 when the controller 102 operates the powertrain 106 in a first mode, and the power for the rim pull and forward speed of the work vehicle 100 is generated solely by the second CVP 116b. Curves 320 and 322 show the relationship between the rim pull and forward speed of the work vehicle 100 when the powertrain 106 is operated in a second mode and a third mode, respectively, and when the power directly from the engine 114 and the power from the second CVP 116b are combined in the transmission 152 to transport the work vehicle 100. It will be apparent to those skilled in the art that... Figure 4The graphs shown indicate that the work vehicle 100 generates sufficient rim pull without exhausting the torque from the CVP 116b, and that the gear ratios used between the engine 114 and / or the CVP 116b and the output shaft 122 of the transmission 118 are appropriately defined in modes 1, 2, and 3.

[0070] Those skilled in the art will understand that, for example, by connecting the forward clutch 206 to the output shaft 130 of the engine 114, configuring both the first mode selection clutch 200 and the reverse clutch 208 to selectively drive the clutch shaft 150, and configuring both the second mode selection clutch 202 and the third mode selection clutch 204 to selectively drive the shift shaft 154, the arrangement of components in the powertrain 106 disclosed herein is simpler and utilizes fewer components than conventional powertrains. This arrangement of components can result in a streamlined and compact package, which can reduce the cost and space requirements of such powertrain 106. Furthermore, as mentioned above, engaging the second CVP 116b with a reduced gear ratio can reduce the reflective inertia from the second CVP 116b, thereby improving the shift quality and operator comfort during operation of the work vehicle 100.

[0071] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. As used herein, unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “the,” “the” are intended to include the plural forms as well. It will be further understood that, when used in this specification, the terms “comprising” and / or “including” specify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0072] As used herein, unless otherwise limited or modified, a list of elements separated by a conjunction (e.g., “and”) and preceded by the phrase “one or more of…” or “at least one of…” indicates a construction or arrangement that potentially includes the individual elements of the list or any combination thereof. For example, “at least one of A, B, and C” or “one or more of A, B, and C” indicates the possibility that: only A; only B; only C; or any combination of two or more of A, B, and C (e.g., A and B; B and C; A and C; or A, B, and C).

[0073] The description of this disclosure has been presented for purposes of illustration and description, but is not intended to be exhaustive or to limit the disclosure to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of this disclosure. The embodiments expressly referenced herein were chosen and described in order to best explain the principles of this disclosure and its practical application, and to enable others skilled in the art to understand this disclosure and recognize the many alternatives, modifications, and variations to the described examples. Therefore, various embodiments and implementations other than those expressly described are within the scope of the appended claims.

Claims

1. A powertrain (106) for a work vehicle (100), comprising: Engine (114); and Transmission device (118), the transmission device (118) comprising: Continuously Variable Power Source (CVP) (116b); A transmission (152) is operably connected to the engine (114) and the continuously variable power source (116b), wherein the transmission (152) includes a first planetary gear set (156) and a second planetary gear set (158). A shift shaft (154) having a shift shaft output gear (230) fixed to the shift shaft (154). A first mode selection clutch (202) has a first input component (202a) that meshes with the output gear (170) of the first planetary gear set (156) and a first output component (202b) connected to the shift shaft (154). The second mode selection clutch (204) has a second input component (204a) that meshes with the output gear (172) of the second planetary gear set (158) and a second output component (204b) connected to the shift shaft (154). Output shaft (122), the output shaft having an output shaft gear (232) driven by the shift shaft output gear (230); The first mode selection clutch (202) and the second mode selection clutch (204) are selectively operable to connect the first input component (202a) to the first output component (202b) or to connect the second input component (204a) to the second output component (204b), thereby transmitting power from the transmission (152) to the output shaft (122).

2. The powertrain (106) according to claim 1, wherein, The first planetary gear set (156) is a low-speed planetary gear set, and the second planetary gear set (158) is a high-speed planetary gear set.

3. The powertrain (106) according to claim 2, wherein, The output gear (170) of the first planetary gear set (156) is the planet carrier (170) of the first planetary gear set (156).

4. The powertrain (106) according to claim 2, wherein, The output gear (172) of the second planetary gear set (158) is the ring gear (172) of the second planetary gear set (158).

5. The powertrain (106) according to claim 1 further includes a clutch shaft (150) and a third mode selection clutch (200), wherein, The third input component (200a) of the third mode selection clutch (200) meshes with both the output gear (214) fixed to the output shaft (216) of the continuously variable power source (116b) and the input gear (168) of the first planetary gear set (156), and the third output component (200b) of the third mode selection clutch (200) is connected to the clutch shaft (150).

6. The powertrain (106) according to claim 5, wherein, The powertrain (106) operates in a first mode, a second mode, and a third mode. In the first mode, the third mode selection clutch (200) is engaged to transmit power to both the clutch shaft (150) and the transmission (152) using power from the continuously variable power source (116b). In the second mode, the first mode selection clutch (202) is engaged and the third mode selection clutch (200) is disengaged. In the third mode, the second mode selection clutch (204) is engaged.

7. The powertrain (106) according to claim 5 further includes a clutch shaft output gear (224) fixed to the clutch shaft (150), wherein, The clutch shaft output gear (224) is operable to transmit power to the transmission (152).

8. The powertrain (106) according to claim 5 further includes a reverse clutch (208), wherein, The input component (208a) of the reverse clutch (208) is driven by the output shaft (130) of the engine (114), and the output component (208b) of the reverse clutch (208) drives the clutch shaft (150).

9. The powertrain (106) according to claim 1 further includes a forward clutch (206), wherein, The input component (206a) of the forward clutch (206) is fixed to the output shaft (130) of the engine, and the output component (206b) of the forward clutch (206) is configured to transmit power directly from the engine (114) to the transmission (152) when the input component (206a) of the forward clutch (206) is engaged with the output component (206b) of the forward clutch (206).

10. The powertrain (106) according to claim 1, wherein, When the output shaft (122) is driven in the first direction, the continuously variable power source (116b) operates in the first direction and the opposite second direction.

11. A transmission (118) for a work vehicle (10) having an engine (114), the transmission (118) comprising: Housing (119), wherein: Continuously Variable Power Source (CVP) (116b); A transmission (152) is operably connected to the engine (114) and the continuously variable power source (116b), wherein the transmission (152) includes a first planetary gear set (156) and a second planetary gear set (158). A shift shaft (154) having a shift shaft output gear (230) fixed to the shift shaft (154). A first mode selection clutch (202) has a first input component (202a) that meshes with the output gear (170) of the first planetary gear set (156) and a first output component (202b) configured to drive the shift shaft (154). A second mode selection clutch (204) having a second input component (204a) engaging with the output gear (172) of the second planetary gear set (158) and a second output component (204b) configured to drive the shift shaft (154); and Output shaft (122), the output shaft being driven by the shift shaft output gear (230); The first mode selection clutch (202) and the second mode selection clutch (204) are selectively operable to connect the first input component (202a) to the first output component (202b) or to connect the second input component (204a) to the second output component (204b), thereby transmitting power from the transmission (152) to the output shaft (122).

12. The transmission device (118) according to claim 11, wherein, The first planetary gear set (156) is a low-speed planetary gear set, and the second planetary gear set (158) is a high-speed planetary gear set, wherein the output gear (170) of the first planetary gear set (156) is the planet carrier (170) of the first planetary gear set (156), and wherein the output gear (172) of the second planetary gear set (158) is the ring gear (172) of the second planetary gear set (158).

13. The transmission device (118) according to claim 11, wherein, It also includes a clutch shaft (150) and a third mode selection clutch (200), wherein a third input component (200a) of the third mode selection clutch (200) meshes with both an output gear (216) fixed to an output shaft (216) of the continuously variable power source (116b) and an input gear (168) of the first planetary gear set (156), and the third output component (200b) of the third mode selection clutch (200) is configured to drive the clutch shaft (150), and The work vehicle (100) operates in the first mode, the second mode, and the third mode. In the first mode, the third mode selection clutch (200) is engaged to transmit power to both the clutch shaft (150) and the transmission (152) using the power generated by the continuously variable power source (116b). In the second mode, the first mode selection clutch (202) is engaged. In the third mode, the second mode selection clutch (204) is engaged.

14. The transmission device (118) according to claim 13 further includes a clutch shaft output gear (224), a reverse clutch (208), and a forward clutch (206) fixed to the clutch shaft (150). in, The clutch shaft output gear (224) is operable to transmit power from the clutch shaft (150) to the transmission (152). The input component (208a) of the reverse clutch is driven by the output shaft (130) of the engine, and the output component (208b) of the reverse clutch (208) drives the clutch shaft (150). The input component (206a) of the forward clutch (206) is fixed to the output shaft (130) of the engine (114), and the output component (206b) of the forward clutch (206) is configured to transmit power directly from the engine (114) to the transmission (152) when the input component (206a) of the forward clutch (206) is engaged with the output component (206b) of the forward clutch (206).

15. The transmission device (118) according to claim 11, wherein, When the output shaft (122) is driven in the first direction, the continuously variable power source (116b) operates in the first direction and the opposite second direction.

Images