Transmission, powertrain, vehicle, and method for operating a transmission

Abstract

This application relates to a transmission, a powertrain system, a vehicle, and a method for operating the transmission. Specifically, a transmission (1) for a vehicle (100) includes: a first shiftable gear unit (10) and a second shiftable gear unit (20); and a sub-transmission unit (30) drivably connected to an output shaft (50), the sub-transmission unit (30) being capable of shifting between at least a low gear and a high gear, the first shiftable gear unit (10) selectively transmitting torque from a first input shaft (11) to the sub-transmission unit (30), and the second shiftable gear unit (20) selectively transmitting torque from a second input shaft (21) to the sub-transmission unit, wherein the transmission (1) is also capable of shifting to a bypass state, in which the second shiftable gear unit (20) shifts to a bypass state, such that power can be transmitted from the second input shaft (21) to the output shaft (50) without passing through the sub-transmission unit (30).

Description

Technical Field

[0001] This disclosure generally relates to vehicles. In specific aspects, this disclosure relates to transmissions, powertrain systems, vehicles, and methods for operating transmissions. This disclosure is applicable to heavy-duty vehicles, such as trucks, buses, and construction equipment, as well as other vehicle types. Specifically, this disclosure is applicable to electric or hybrid vehicles. Although this disclosure may be described with respect to specific vehicles, it is not limited to any particular vehicle. Background Technology

[0002] A range gear is typically used in multi-speed transmissions, especially in heavy-duty vehicles such as trucks, to provide a wider variety of gear ratios. Essentially, a range gear is a way of using gears with different positions, such as low and high gears, to increase the number of available gear ratios.

[0003] Efforts are being made to develop improved technologies for multi-speed transmissions, including auxiliary transmission units, such as improving shifting to achieve smoother shifts. Specifically, the transmission needs to be improved to enable shifting without interrupting torque.

[0004] definition

[0005] To facilitate reading this disclosure, some commonly used transmission ratios are defined below.

[0006] The gear ratio of the first / second shiftable gear mechanism refers to the ratio of the rotational speed of the first / second input shaft to the rotational speed of the output shaft of the first / second gear mechanism. In some non-limiting examples of this disclosure, the output shaft of the first / second gear mechanism may be a main shaft. However, in bypass mode, the output shaft of the second shiftable gear mechanism may be the final output shaft.

[0007] The gear ratio of the auxiliary transmission is defined herein as the ratio of the rotational speed of the input shaft to the rotational speed of the output shaft. In some non-limiting examples of this disclosure, the input shaft of the auxiliary transmission may be the main shaft.

[0008] The transmission ratio of the first / second reduction gear set is defined as the ratio of the rotational speed of the first / second power unit to the rotational speed of the first / second input shaft.

[0009] The transmission ratio of a bypass gear refers to the ratio of the rotational speed of the second input shaft to the rotational speed of the output shaft when the bypass gear transmits power.

[0010] The gear ratio of the set of high-speed gears is defined as the ratio of the rotational speed of the first / second input shaft to the rotational speed of the output shaft when the transmission is in high-speed gear.

[0011] The gear ratio of the set of low gears is defined as the ratio of the rotational speed of the first / second input shaft to the rotational speed of the output shaft when the transmission is in a low gear.

[0012] The total transmission ratio of the gearbox from the first / second power unit to the output shaft is defined as the ratio of the rotational speed of the first / second power unit to the rotational speed of the output shaft.

[0013] Furthermore, throughout this disclosure, the terms "rotatably connected" and "rotatably coupled" should be interpreted as meaning that components of a transmission are connected to another component of the transmission in such a way that these components rotate in the same direction and at the same speed. Therefore, rotatably coupled components rotate at the same speed in the same direction about the same axis and can transmit torque to each other. The term "rotatably connected" should be interpreted as "selectively connected to rotate together."

[0014] Throughout this disclosure, the terms “driveably connected” and “driveably coupled” should be interpreted as meaning that the components of the transmission are arranged in such a way that they can transmit torque to each other and rotate at speeds proportional to each other, so that their transmission ratio is constant. The term “driveably connected” should be interpreted as “selectively connected to transmit torque through a defined transmission ratio.” Summary of the Invention

[0015] According to a first aspect of the invention, a transmission for a vehicle is provided, the transmission including a first shiftable gear assembly and a second shiftable gear assembly. The first shiftable gear assembly is capable of shifting between a first plurality of gears with different gear ratios, and the second shiftable gear assembly is capable of shifting between a second plurality of gears with different gear ratios. The first shiftable gear assembly is drivably connected to a first input shaft, and the second shiftable gear assembly is drivably connected to a second input shaft. The first input shaft is configured to be drivably connected to a first power unit, and the second input shaft is configured to be drivably connected to a second power unit.

[0016] Furthermore, the transmission includes a secondary transmission unit that is drivably connected to the output shaft. The secondary transmission unit can shift between at least a low gear and a high gear, wherein the gear ratio of the secondary transmission unit in the low gear is greater than the gear ratio of the secondary transmission unit in the high gear.

[0017] A first shiftable gear unit is configured to selectively transmit torque from a first input shaft to a sub-transmission unit using one of a first plurality of gears, and a second shiftable gear unit is configured to selectively transmit torque from a second input shaft to a sub-transmission unit using one of a second plurality of gears, such that the sub-transmission unit, together with the first shiftable gear unit and / or the second shiftable gear unit, provides a set of low gears and a set of high gears between one or both of the input shafts and the output shaft.

[0018] In addition, the transmission can be shifted to a bypass state. In the bypass state, the second shiftable gear device shifts to the bypass state, which is included in the second plurality of gears, so that power can be transmitted from the second input shaft to the output shaft without passing through the auxiliary transmission device.

[0019] A first aspect of this disclosure seeks to provide a transmission that is improved in at least some respects. Specifically, the first aspect seeks to provide a transmission capable of shifting gears without interrupting torque (i.e., maintaining power transmission to the output shaft). Technical benefits may include improved vehicle performance in terms of driving dynamics, driver comfort, and / or energy efficiency.

[0020] Optionally, in some examples, including at least one preferred example, the auxiliary transmission unit can also shift to neutral, and in bypass mode, the auxiliary transmission unit can shift between high gear, low gear, and neutral without interruption of torque between the second input shaft and the output shaft. Technical benefits may include shifting between the states of the auxiliary transmission unit without interrupting torque. Therefore, good performance in terms of driving dynamics and / or energy efficiency can be provided for the vehicle.

[0021] Optionally, in some examples, including at least one preferred example, the transmission further includes a first reduction gear set, wherein the first input shaft is configured to be driven connected to a first power unit via the first reduction gear set, and / or a second reduction gear set, wherein the second input shaft is configured to be driven connected to a second power unit via the second reduction gear set. Technical benefits compared to directly connecting the input shaft may include greater flexibility in the arrangement of the power unit. Furthermore, the appropriate overall transmission ratio from the power unit to the output shaft can be achieved using the gear ratios of the reduction gear sets.

[0022] Optionally, in some examples, including at least one preferred example, the gear ratio of the first reduction gear set is different from the gear ratio of the second reduction gear set. The gear ratio of the reduction gear set refers herein to the ratio between the rotational speed of the corresponding power unit and the rotational speed of the corresponding input shaft. By combining the reduction gear set with multiple gears of the first and / or second shiftable gear set and / or auxiliary transmission set, multiple total gear ratios from the corresponding power unit to the output shaft of the transmission can be achieved. Therefore, technical benefits may include providing an appropriate number of total gear ratios from the corresponding power unit to the output shaft.

[0023] Optionally, in some examples, including at least one preferred example, the first shiftable gear assembly includes a first gear engagement member configured to select one of a first plurality of gears of the first shiftable gear assembly, and wherein the second shiftable gear assembly includes a second gear engagement member configured to select one of a second plurality of gears of the second shiftable gear assembly, the second plurality of gears including a bypass gear. Technical benefits may include convenient gear selection within each shiftable gear assembly.

[0024] Optionally, in some examples, including at least one preferred example, the transmission further includes a main shaft and a plurality of main gear sets, each main gear set including a plurality of gears, wherein the main shaft is rotatably connected to or can be connected to the gears in the plurality of gears of each main gear set, as well as the rotating portion of the auxiliary transmission unit. Technical benefits may include facilitating the location of the gears (excluding bypass gears) of the first and second shiftable gear sets on a common main shaft, and interconnecting the plurality of gears with the auxiliary transmission unit in a simple manner with very few parts.

[0025] Optionally, in some examples, including at least one preferred example, the transmission further includes a common countershaft of gears rotatably connected to a common gear set, wherein the common gear set is one of a plurality of primary gear sets. A first gear engagement member is configured to selectively engage a first input shaft to the common countershaft, and a second gear engagement member is configured to selectively engage a second input shaft to the common countershaft. Technical benefits may include providing a transmission with fewer parts because the two shiftable gear units can use the common gear set.

[0026] Optionally, in some examples, including at least one preferred example, the secondary shaft is arranged between the first input shaft and the second input shaft such that the secondary shaft is coaxial and aligned with at least one of the first and second input shafts. Technical benefits may include a compact transmission design.

[0027] Optionally, in some examples, including at least one preferred example, the transmission further includes a bypass gear set comprising a plurality of gears, wherein the bypass gear set is drivably connected to the output shaft, and wherein, in the bypass position, a second gear engagement member is configured to rotatably connect a second input shaft to the gears of the bypass gear set. Technical benefits may include the efficient and compact arrangement of the bypass gears, thereby facilitating shifting without interrupting torque, particularly when shifting between gear positions of the auxiliary transmission unit.

[0028] Optionally, in some examples, including at least one preferred example, the transmission further includes a differential gear assembly droopingly connected to the output shaft and a corresponding drive shaft of the vehicle's drive axle. Technical benefits may include allowing different speeds at different wheels of the drive axle.

[0029] Optionally, in some examples, including at least one preferred example, in bypass mode, the transmission ratio from the second input shaft to the output shaft is less than the transmission ratio of the highest gear in the set of low gears and greater than the transmission ratio of the lowest gear in the set of high gears. The transmission ratio of the second input shaft to the output shaft is defined herein as the ratio of the rotational speed of the second input shaft to the rotational speed of the output shaft when the second input shaft and output shaft are drivenly connected via a second shiftable gear mechanism. Therefore, when shifting from a low gear to a high gear through different gears, the bypass gear is located sequentially between the low gear and the high gear. Technical benefits may include the ability to conveniently shift through a series of gears without interrupting torque.

[0030] Optionally, in some examples, including at least one preferred example, the auxiliary transmission unit includes a planetary gear set comprising a center gear, a planet carrier carrying one or more planetary gears, and a ring gear. Technical benefits may include a compact design for the auxiliary transmission unit.

[0031] Optionally, in some examples, including at least one preferred example, the bypass gear set is connected to the planet carrier of the planetary gear set. This allows for a suitable gear ratio in the auxiliary transmission unit.

[0032] Optionally, in some examples, including at least one preferred example, the center gear of the planetary gear set is driven to connect to the main shaft. This allows for a suitable transmission ratio in the secondary gearbox.

[0033] Optionally, in some examples, including at least one preferred example, in the high-speed gear state of the auxiliary transmission, the ring gear and the center gear of the planetary gear set are fixed to each other for co-rotation. Technical benefits may include an appropriate gear ratio in the high-speed gear state.

[0034] Optionally, in some examples, including at least one preferred example, the ring gear of the planetary gear set is connected to a fixed node of the transmission in the low-speed gear position of the auxiliary transmission unit. Technical benefits may include a suitably large gear ratio in the low-speed gear position.

[0035] Optionally, in some examples, including at least one preferred example, the auxiliary transmission unit includes an auxiliary transmission shifting member for selecting a high-speed gear state and a low-speed gear state. Technical benefits may include facilitating shifting between gear states of the auxiliary transmission unit.

[0036] According to a second aspect of this disclosure, a powertrain system for a vehicle is provided, the powertrain system comprising a first power unit, a second power unit, and a transmission according to the first aspect. The advantages and beneficial features of the powertrain system according to the second aspect are largely similar to the advantages and beneficial features of the transmission according to the first aspect.

[0037] According to a third aspect of this disclosure, a vehicle is provided, the vehicle including a powertrain system according to the second aspect. The advantages and beneficial features of the vehicle according to the third aspect are largely similar to the advantages and beneficial features of the transmission according to the first aspect.

[0038] According to a fourth aspect of this disclosure, a method for operating a transmission according to the first aspect is provided, the method comprising:

[0039] - Allows the transmission to operate in either a high gear or a low gear.

[0040] - Shift the transmission to bypass mode, and

[0041] - When the transmission is in bypass mode, the auxiliary transmission unit is shifted from a high gear to a low gear, and vice versa.

[0042] A fourth aspect of this disclosure seeks to provide a method for operating a transmission that is improved in at least some respects. Specifically, a first aspect seeks to provide a method for shifting gears without interrupting torque. Technical benefits may include improved vehicle performance in terms of driving dynamics, driver comfort, and / or energy efficiency.

[0043] Those skilled in the art will understand that the disclosed aspects, examples (including any preferred examples), and / or appended claims can be appropriately combined with each other. Additional features and advantages are disclosed in the following description, claims, and drawings, and will be apparent in part to those skilled in the art or recognized by practicing this disclosure as described herein. Attached Figure Description

[0044] The example is described in more detail below with reference to the accompanying drawings.

[0045] Figure 1 This is an example vehicle based on the example.

[0046] Figure 2 The transmission is illustrated schematically according to the example.

[0047] Figure 3 The auxiliary transmission is illustrated schematically according to the example.

[0048] Figure 4 A transmission based on another example is shown schematically.

[0049] Figure 5 A transmission based on another example is shown schematically.

[0050] Figure 6 A transmission based on another example is shown schematically.

[0051] Figure 7 This is a flowchart based on the example method. Detailed Implementation

[0052] The detailed description set forth below provides information and examples of the disclosed technology in sufficient detail to enable those skilled in the art to practice this disclosure.

[0053] The purpose of this disclosure is to mitigate at least one disadvantage of the prior art, or at least to provide a suitable alternative. Specifically, the purpose of this disclosure is to avoid torque interruption during gear shifts. This improves the overall performance and driving characteristics of the vehicle. The problem is solved by providing a gearbox and a method of operating the gearbox. Thus, a gearbox and vehicle with improved performance and energy efficiency can be provided.

[0054] Figure 1 A vehicle 100 in the form of a heavy-duty tractor truck is schematically depicted. The vehicle includes a transmission 1, which is included in a powertrain 2.

[0055] Figure 2 This is a schematic representation of a transmission 1 according to an example of the present disclosure. As can be seen from the figure, the transmission 1 can be configured to connect to a first power unit 15 and a second power unit 25. The respective power units 15 / 25 can be driven to a first input shaft 11 and a second input shaft 21, respectively. For example, first and second reduction gear sets 13 / 23 can be used to drive the respective power units 15 / 25 to the respective input shafts 11, 21. The first and second reduction gear sets 13 / 23 can have different gear ratios.

[0056] A first input shaft 11 can be connected to a first shiftable gear unit 10. Similarly, a second input shaft 21 can be connected to a second shiftable gear unit 20. The first shiftable gear unit 10 can be configured to selectively transmit torque from the first input shaft 11 to the auxiliary transmission unit 30 using a first plurality of gears with different gear ratios. Likewise, the second shiftable gear unit 20 can be configured to selectively transmit torque from the second input shaft 21 to the auxiliary transmission unit 30 using a second plurality of gears with different gear ratios. Figure 2 In the example shown, the first shiftable gear unit 10 and the second shiftable gear unit 20 can each be connected to two gear states, that is, the first plurality of gears and the second plurality of gears each include two gears. However, it is conceivable that any number of gears in the first and second plurality of gears can be implemented.

[0057] The auxiliary transmission unit 30 can be connected to or may be connected to the output shaft 50 of the transmission 1. The auxiliary transmission unit 30 can be configured to selectively transmit torque from one or both of the first shiftable gear unit 10 and the second shiftable gear unit 20 to the output shaft 50 using different auxiliary transmission states (such as high-speed and low-speed states with different gear ratios). Thus, the gear ratio of the auxiliary transmission unit 30 in the low-speed state can be greater than the gear ratio of the auxiliary transmission unit 30 in the high-speed state. Therefore, by combining the first and second shiftable gear units and the auxiliary transmission unit 30, the transmission 1 provides a set of low-speed gears and a set of high-speed gears to the output shaft 50 from one or both of the first power unit 15 and the second power unit 25. It is conceivable that the auxiliary transmission unit 30 may include additional auxiliary transmission states, such as one or more intermediate auxiliary transmission states.

[0058] Furthermore, the transmission 1 may include a bypass gear. The bypass gear can be considered a direct connection between one of the input shafts (here, the second input shaft 21) and the output shaft 50. Therefore, using the bypass gear, torque can be transmitted from the second input shaft 21 to the output shaft 50 without passing through the auxiliary transmission unit 30. Thus, shifting between auxiliary transmission states can be performed without interrupting torque. The bypass gear may be part of a second plurality of selectable gears in the second shiftable gear unit 20.

[0059] In some examples, the first shiftable gear mechanism 10 may include a first gear engagement member 17. Correspondingly, the second shiftable gear mechanism 10 may include a second gear engagement member 27. The first and second gear engagement members 17 / 27 may be clutches. Figure 2As shown, the first gear engagement member 17 can be configured to selectively connect the first input shaft 11 to corresponding pinions 61a / 62a of a plurality of main gear sets 61 / 62, each main gear set 61 / 62 including a plurality of gears, such as at least one pinion 61a / 62a and at least one gear 61b / 62b. The gears 61b / 62b of the main gear sets 61 / 62 can be arranged on the main shaft 60. Furthermore, the second gear engagement member 27 can be configured to selectively connect the second input shaft 21 to some of the pinions 61a / 62a of the main gear sets 61 / 62 connected to the main shaft 60. In other words, at least one common gear set 81 (in...) can exist. Figure 2 The first gear set 81 (identical to gear set 62) is used by both the first and second shiftable gear units 10 / 20. At least one common gear set 81 may include a pinion 62a arranged on a common countershaft 80. Thus, both the first power unit 15 and the second power unit 25 may be drivably connected to the output shaft 50 via the common countershaft 80. The main shaft 60 may also be rotatably connected to or be connected to a rotating member of the auxiliary transmission unit 30. A bypass gear is achieved by a bypass gear set 90, which includes a plurality of gears, such as at least one pinion 90a and at least one large gear 90b. The large gear 90b may be rotatably connected to the output shaft 50. Thus, the second gear engagement member 27 may be configured to selectively connect the second input shaft 21 via the common countershaft 80 to one of the at least one common gear set 81, or to the bypass gear set 90. When the second gear engagement member 27 connects the second input shaft 21 to the pinion 90a of the bypass gear set 90, the direct connection between the second input shaft 21 and the output shaft 50 has the gear ratio of the bypass gear set 90. In this bypass mode, the auxiliary transmission unit 30 and / or the first shiftable gear unit 10 can shift gears while still supplying torque from the second power unit 25 to the output shaft 50. Therefore, the bypass mode can be used to shift gears between auxiliary transmission modes without interrupting torque.

[0060] As already mentioned, both the first shiftable gear unit 10 and the second shiftable gear unit 20 can include two or more gear positions. Accordingly, the transmission 1 can include two or more main gear sets 61 / 62 and / or one or more common gear sets 81.

[0061] In bypass mode, the gear ratio of the transmission 1 from the second input shaft 21 to the output shaft 50 is less than the gear ratio of the highest gear in the set of low gears and greater than the gear ratio of the lowest gear in the set of high gears. In other words, the gear ratio of the bypass mode is between the gear ratios of the set of low gears and the gear ratios of the set of high gears. Therefore, when shifting from the lowest gear to the highest gear through the transmission, for example, when accelerating the vehicle 100, the low gear is followed by the bypass mode. When the bypass mode is engaged, the auxiliary transmission unit 30 shifts from a low gear state to a high gear state. Thereafter, the high gear is used. Therefore, seamless shifting performance can be achieved without interrupting torque. Furthermore, even when shifting through the bypass mode, a convenient shift sequence from low gear to high gear can be achieved.

[0062] A non-limiting example of a shift sequence is further illustrated by a non-limiting example of a transmission 1, wherein both the first and second shiftable gear units 10 / 20 have two gear states. Accordingly, in this example, the transmission 1 may have two main gear sets 61 / 62, one of which may be a common gear set 81. In this example, the first shiftable gear unit 10 may have Figure 2 The gear positions are marked as L and H. Furthermore, the second shiftable gear mechanism 20 may have... Figure 2 The two gear states are labeled A and B. Similarly, in this example, the auxiliary transmission unit 30 can have two gear states: a high gear state HR and a low gear state LR. In this example, the first and second shiftable gear units 10 / 20 and the auxiliary transmission unit 30 together provide a variety of possible shift combinations, as shown in Table 1. Table 1 shows the gears and gear combinations generated when the auxiliary transmission unit 30, the first shiftable gear unit 10, and the second shiftable gear unit 20 are in one of their respective positions. Odd-numbered gears here are gears where the first power unit 15 is driven engaged and the second power unit 25 is driven disengaged from the transmission 1. Even-numbered gears are gears where the first power unit 15 is disengaged and the second power unit 25 is driven engaged with the transmission 1. The bypass gear here is the fourth gear. Therefore, in this example, there are seven gears that connect one of the power units 15 / 25 to the output shaft 50 at different gear ratios. Furthermore, these gears can be combined in various ways to simultaneously drive both the first power unit 15 and the second power unit 25 to the output shaft 50.

[0063]

[0064] Go to Figure 3The following provides a more detailed example of the auxiliary transmission assembly 30. By way of example only, the auxiliary transmission assembly 30 may include a planetary gear set 31. The planetary gear set 31 may include a center gear 32, a planet carrier 33 carrying one or more planetary gears 34, and a ring gear 35. Furthermore, the auxiliary transmission assembly 30 may include an auxiliary transmission shift member 38 for selectively selecting one of the auxiliary transmission states. In some examples, the auxiliary transmission shift member 38 may be arranged to selectively connect the ring gear 35 to a fixed node 70 of the transmission 1. When the ring gear 35 is fixed to the fixed node 70 of the transmission 1 in steering, i.e., when the ring gear 35 is stationary, a relatively large gear ratio of the auxiliary transmission assembly 30 is achieved. Therefore, this configuration is suitable for low-speed conditions. Additionally, the auxiliary transmission shift member 38 may be arranged to selectively connect the ring gear 35 to another component of the planetary gear set 31. Figure 3 In the non-limiting example shown, the ring gear 35 can be coupled to the center gear 32. This allows for a relatively small gear ratio, in this example a direct 1:1 speed relationship, which may be suitable for high-speed gears. In some examples, the output shaft 50 can be rotatably connected to the planet carrier 33, and the center gear 32 can be rotatably connected to the main shaft 60. However, other combinations are conceivable to those skilled in the art. For example, the output shaft 50 can be rotatably connected to the center gear 32, and the main shaft 60 can be rotatably connected to the planet carrier 33.

[0065] Figure 4 Another exemplary embodiment of the transmission 1 according to this disclosure is shown. Here, the first shiftable gear assembly 10 may include a first input shaft gear engagement member 17a and a main shaft gear engagement member 17b. The first input shaft gear engagement member 17a may be configured to selectively engage a first input shaft 11 to a common countershaft 80, thereby drivingly connecting the input shaft 11 to a common gear set 81, while a pinion 61a of another main gear set 61 is fixedly connected to the input shaft 11. The main shaft gear engagement member 17b may be configured to selectively engage a main shaft 60 to a large gear 61b of the main gear set 61. If the transmission includes more than two main gear sets (61, 62), the transmission 1 may include one main shaft engagement member 17b for each main gear set 61 (not part of the common gear set 81). Similarly, a second input shaft gear engagement member 27a may be configured to selectively engage a second input shaft 21 to a common countershaft 80, while a pinion 90a of a bypass gear set 90 is fixedly connected to the second input shaft 21. The output shaft gear engagement member 27b can be configured to selectively engage the large gear 90b to the output shaft 50. Figure 4The advantage of this implementation scheme is that more parts of the transmission can be in neutral, that is, fewer parts are rotating when not needed. In addition, the pinions 61a / 90a of the main gear set 61 and the bypass gear set 90 can be directly connected to or integrated into the corresponding input shafts 11 / 21, which can achieve a more robust and rigid structure.

[0066] Figure 5 Another exemplary embodiment according to this disclosure is shown. Here, the input shafts (11, 21) may be arranged on different shafts. Similar to the embodiments described above, the input shafts are respectively connected to the first shiftable gear assembly 10 and the second shiftable gear assembly 20. As previously stated, at least one common gear set 81 is at least one of the main gears 61 / 62. Figure 4 In the example shown, there is a common gear set 81, which is the main gear set 62. Figure 5 The example differs from the example explained above in that at least one common gear 81 comprises two pinions 62a / 62a', both of which are rotatably connected to a large gear 62b. The pinions 62a / 62a' can then be connected to corresponding countershafts 80a / 80b of the first and second shiftable gear units 10 / 20. In other words, according to this embodiment, the transmission 1 does not include a common countershaft 80. Instead, two separate countershafts 80a / 80b can be connected to two corresponding pinions 62a / 62a'. Thus, by drivingly connecting the first input shaft 11 to the first countershaft 80a, the first shiftable gear unit 10 can select at least one common gear represented by the common gear set 81. Furthermore, by drivingly connecting the second input shaft 21 to the second countershaft 80b, the second shiftable gear unit 20 can also select at least one common gear. Because the input shafts 11 / 21 are not coaxially arranged, flexible arrangements of the power units 15 / 25 are possible.

[0067] Figure 6 Another exemplary embodiment of this disclosure is shown. According to this embodiment, the output shaft 50 may be configured to be drivably connected to a differential gear assembly 55. The differential gear assembly 55 is then arranged to drive corresponding drive shafts 51a / 51b of the axle of the vehicle 100. The drive shafts 51a / 51b are connected to corresponding ground engagement members 52a / 52b, such as wheels.

[0068] Figure 6 The diagram also shows the power units 15 / 25 arranged in an axially overlapping manner when viewed from the axial direction of the input shafts 11 / 21. This axially overlapping arrangement could obviously also be... Figure 2 and Figure 4 This is one alternative to the other embodiments shown. The advantage of the axially overlapping arrangement is that it provides a transmission 1 that can occupy less space in the vehicle 100.

[0069] Figure 7 A method for a transmission 1 according to this disclosure is shown. The method may include the following actions:

[0070] Action S1: Operate the transmission 1 in either high gear or low gear mode.

[0071] Action S2: Shift transmission 1 to bypass mode.

[0072] As detailed above, shifting to the bypass position may include shifting the second shiftable gear device 20 to the bypass position by shifting the second gear engagement member 27 to connect the second input shaft 21 to the bypass gear set 90.

[0073] Action S3: When the transmission 1 is in bypass mode, the auxiliary transmission device 30 is shifted from high gear to low gear, and vice versa.

[0074] Using the bypass mode, transmission 1 can switch from a low gear to a high gear and vice versa without interrupting torque, because the torque path goes directly from the second input shaft 20 through the bypass gear set 90 to the output shaft 50, without passing through the auxiliary transmission device 30.

[0075] The actions described in any of the exemplary aspects of this document are provided for example and discussion. These actions may be performed by hardware components, may be embodied in machine-executable instructions to cause a processor to perform these actions, or may be performed by a combination of hardware and software. Although a particular order of method actions may be shown or described, the order of actions may differ. Furthermore, two or more actions may be performed simultaneously or partially simultaneously.

[0076] In this context, a "drive connection" between two rotating parts means that torque can be transmitted between the parts in proportion to their rotational speeds. When two gears are driven together, torque can be transmitted between them. This can be achieved by engaging the gears, either by meshing the first gear with the second gear, which in turn meshes with the third gear, or by meshing the first gear with the second gear, which rotatably connects to the third gear, which in turn meshes with the fourth gear. Therefore, for a drive connection, the two gears do not necessarily need to mesh. It is sufficient that rotation of one gear necessarily causes rotation of the other.

[0077] The terminology used herein is for descriptive purposes only and is not intended to limit this disclosure. As used herein, unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “described” are intended to also include the plural forms. As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items. It should also be understood that the terms “comprising” and / or “including”, when used herein, indicate the presence of the stated features, integers, actions, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, actions, steps, operations, elements, components, and / or groups thereof.

[0078] It should be understood that although the terms first, second, etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used only to distinguish one element from another. For example, without departing from the scope of this disclosure, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element.

[0079] In this document, relative terms such as “below,” “above,” “upper,” “lower,” “horizontal,” or “vertical” may be used to describe the relationship between one element and another, as illustrated in the figures. It should be understood that these terms, along with those discussed above, are intended to cover different device orientations in addition to those depicted in the figures. It should be understood that when an element is referred to as “connected” or “coupled” to another element, the element may be directly connected or coupled to the other element, or there may be intermediate elements present. In contrast, when an element is referred to as “directly connected” or “directly coupled” to another element, there are no intermediate elements present.

[0080] Unless otherwise defined, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. It should also be understood that, unless expressly defined herein, terms used herein shall be interpreted as having the same meaning as they have in the context of this specification and the relevant field, and not in an idealized or overly formal sense.

[0081] It should be understood that this disclosure is not limited to the aspects described above and shown in the accompanying drawings; rather, those skilled in the art will recognize that many changes and modifications can be made within the scope of this disclosure and the appended claims. Aspects have been disclosed in the drawings and description for illustrative purposes only and not for limiting purposes, and the scope of this disclosure is set forth in the appended claims.

[0082] In the following, possible features and combinations of features of this disclosure are presented as a series of numbered examples.

[0083] Example 1: A transmission (1) for a vehicle (100) comprising:

[0084] - A first shiftable gear mechanism (10) and a second shiftable gear mechanism (20), the first shiftable gear mechanism (10) being capable of shifting between a first plurality of gears with different gear ratios, and the second shiftable gear mechanism (20) being capable of shifting between a second plurality of gears with different gear ratios, wherein the first shiftable gear mechanism (10) is drivably connected to a first input shaft (11), and the second shiftable gear mechanism (20) is drivably connected to a second input shaft (21), wherein the first input shaft (11) is configured to be drivably connected to a first power unit (15), and the second input shaft (21) is configured to be drivably connected to a second power unit (25), and

[0085] - A secondary transmission unit (30), drivably connected to an output shaft (50), wherein the secondary transmission unit (30) is capable of shifting between at least a low gear state and a high gear state, wherein the gear ratio of the secondary transmission unit (30) in the low gear state is greater than the gear ratio of the secondary transmission unit (30) in the high gear state, wherein a first shiftable gear unit (10) is configured to selectively transmit torque from a first input shaft (11) to the secondary transmission unit (30) using one of the first plurality of gears, and a second shiftable gear unit (20) is configured to selectively transmit torque from a second input shaft (21) to the secondary transmission unit using one of the second plurality of gears, such that the secondary transmission unit (30), together with the first shiftable gear unit (10) and / or the second shiftable gear unit (20), provides a set of low gears and a set of high gears between one or both of the input shafts (11, 21) and the output shaft (50).

[0086] The transmission (1) is also capable of shifting to a bypass mode, in which the second shiftable gear device (20) shifts to a bypass mode, which is included in the second plurality of gears, so that power can be transmitted from the second input shaft (21) to the output shaft (50) without passing through the auxiliary transmission device (30).

[0087] Example 2: According to the transmission (1) of Example 1, wherein the auxiliary transmission device (30) is also capable of shifting to neutral, and wherein in the bypass state, the auxiliary transmission device (30) is capable of shifting between the high gear state, the low gear state and the neutral state, and the torque between the second input shaft (21) and the output shaft (50) is not interrupted.

[0088] Example 3: The transmission (1) according to Example 1 or 2 further includes:

[0089] A first reduction gear set (13), wherein the first input shaft (11) is configured to be driven to the first power unit (15) via the first reduction gear set (13), and / or

[0090] The second reduction gear set (23), wherein the second input shaft (21) is configured to be drivenly connected to the second power unit (25) via the second reduction gear set (23).

[0091] Example 4: According to the transmission (1) of Example 3, the transmission ratio of the first reduction gear set (13) is different from the transmission ratio of the second reduction gear set (23).

[0092] Example 5: A transmission (1) according to any of the preceding examples, wherein the first shiftable gear unit (10) includes a first gear engagement member (17) configured to select one of a first plurality of gears of the first shiftable gear unit (10), and wherein the second shiftable gear unit (20) includes a second gear engagement member (27) configured to select one of a second plurality of gears of the second shiftable gear unit (20), the second plurality of gears including the bypass gear.

[0093] Example 6: The transmission (1) according to any one of the preceding examples further includes a main shaft (60) and a plurality of main gear sets (61, 62), each main gear set (61, 62) including a plurality of gears (61a, 61b, 62a, 62b), wherein the main shaft (60) is rotatably connected to or can be connected to the gears (61b, 62b) of the plurality of gears in each main gear set (61, 62) and the rotating portion of the auxiliary transmission device (30).

[0094] Example 7: The transmission (1) according to Example 6 further includes at least one spindle gear engagement member (17b) configured to selectively engage the spindle (60) with a gear (61b) of one of the plurality of gears in the main gear set (61).

[0095] Example 8: The transmission (1) according to Example 6 or 7, which is subordinate to Example 5, further includes a common countershaft (80) rotatably connected to a gear of a common gear set (81), wherein the common gear set (81) is one of the plurality of master gear sets (61, 62), wherein a first gear engagement member (17) is configured to selectively engage a first input shaft (11) to the common countershaft (80), and a second gear engagement member (27) is configured to selectively engage a second input shaft (21) to the common countershaft (80).

[0096] Example 9: The transmission (1) according to Example 8, wherein the secondary shaft (80) is arranged between the first input shaft (11) and the second input shaft (21) such that the secondary shaft (80) is coaxial and aligned with at least one of the first input shaft (11) and the second input shaft (21).

[0097] Example 10: The transmission (1) according to Examples 5 to 9 further includes a bypass gear set (90) comprising a plurality of gears (90a, 90b), wherein the bypass gear set (90) is drivably connected to the output shaft (50), wherein in the bypass gear state, the second gear engagement member (27) is configured to rotatably connect the second input shaft (21) to the gear (90a) of the bypass gear set (90).

[0098] Example 11: The transmission (1) according to Example 10 further includes an output shaft gear engagement member (27b) configured to selectively engage the output shaft (50) with a gear (90b) among the plurality of gears (90a, 90b) of the bypass gear set (90).

[0099] Example 12: The transmission (1) according to any one of the preceding examples further includes a differential gear assembly (55) drivably connected to the output shaft (50) and the respective drive shafts (51a, 51b) of the drive axle of the vehicle (100).

[0100] Example 13: The transmission (1) according to any one of the preceding examples, wherein in the bypass state, the transmission ratio of the transmission (1) from the second input shaft (21) to the output shaft (50) is less than the transmission ratio of the highest gear in the set of low gears and greater than the transmission ratio of the lowest gear in the set of high gears.

[0101] Example 14: The transmission (1) according to any of the preceding examples, wherein the auxiliary transmission device (30) includes a planetary gear set (31), the planetary gear set (31) including a center gear (32), a planet carrier (33) carrying one or more planetary gears (34) and a ring gear (35).

[0102] Example 15: The transmission (1) according to Example 12, wherein the gear (90b) of the bypass gear set (90) is connected to or can be connected to the planet carrier (33) of the planetary gear set (31).

[0103] Example 16: A transmission (1) according to any one of Examples 12 to 13, wherein the central gear (32) of the planetary gear set (31) is driven to be connected to the main shaft.

[0104] Example 17: A transmission (1) according to any one of Examples 12 to 14, wherein in the high-speed gear state of the auxiliary transmission device (30), the ring gear (35) of the planetary gear set (31) and the center gear (32) of the planetary gear set (31) are fixed to each other to rotate together.

[0105] Example 18: A transmission (1) according to any one of Examples 12 to 15, wherein in the low gear state of the auxiliary transmission device (30), the ring gear (35) of the planetary gear set (31) is connected to the fixed node (70) of the transmission (1).

[0106] Example 19: The transmission (1) according to any one of the preceding examples, wherein the auxiliary transmission device (30) includes an auxiliary transmission shift member (38) for selecting the high gear state and the low gear state.

[0107] Example 20: A powertrain system (2) for a vehicle (100) comprising a first power unit (15), a second power unit (25) and a transmission (1) according to any of the preceding examples.

[0108] Example 21: A vehicle (100) including the powertrain system according to Example 20.

[0109] Example 22: A method for operating a transmission (1) according to any one of Examples 1 to 19, comprising:

[0110] - To operate the transmission (1) in one of the high-speed and low-speed states (S1),

[0111] - Shift the transmission (1) to the bypass position (S2), and

[0112] - When the transmission (1) is set to the bypass state, the auxiliary transmission device (30) is shifted from the high-speed state to the low-speed state (S3), and vice versa.

Claims

1. A transmission (1) for a vehicle (100), the transmission comprising: - A first shiftable gear mechanism (10) and a second shiftable gear mechanism (20), the first shiftable gear mechanism (10) being capable of shifting between a first plurality of gears with different gear ratios, and the second shiftable gear mechanism (20) being capable of shifting between a second plurality of gears with different gear ratios, wherein the first shiftable gear mechanism (10) is drivably connected to a first input shaft (11), and the second shiftable gear mechanism (20) is drivably connected to a second input shaft (21), wherein the first input shaft (11) is configured to be drivably connected to a first power unit (15), and the second input shaft (21) is configured to be drivably connected to a second power unit (25), and - A secondary transmission unit (30), drivably connected to an output shaft (50), wherein the secondary transmission unit (30) is capable of shifting between at least a low gear state and a high gear state, wherein the gear ratio of the secondary transmission unit (30) in the low gear state is greater than the gear ratio of the secondary transmission unit (30) in the high gear state, wherein a first shiftable gear unit (10) is configured to selectively transmit torque from a first input shaft (11) to the secondary transmission unit (30) using one of the first plurality of gears, and a second shiftable gear unit (20) is configured to selectively transmit torque from a second input shaft (21) to the secondary transmission unit using one of the second plurality of gears, such that the secondary transmission unit (30), together with the first shiftable gear unit (10) and / or the second shiftable gear unit (20), provides a set of low gears and a set of high gears between one or both of the input shafts (11, 21) and the output shaft (50). The transmission (1) is also capable of shifting to a bypass mode, in which the second shiftable gear device (20) shifts to a bypass mode, which is included in the second plurality of gears, so that power can be transmitted from the second input shaft (21) to the output shaft (50) without passing through the auxiliary transmission device (30).

2. The transmission (1) according to claim 1, wherein the auxiliary transmission device (30) is also capable of shifting to neutral, and wherein in the bypass state, the auxiliary transmission device (30) is capable of shifting between the high-speed state, the low-speed state and the neutral state, and the torque between the second input shaft (21) and the output shaft (50) is not interrupted.

3. The transmission (1) according to claim 1 or 2, further comprising: A first reduction gear set (13), wherein the first input shaft (11) is configured to be driven to the first power unit (15) via the first reduction gear set (13), and / or The second reduction gear set (23), wherein the second input shaft (21) is configured to be drivenly connected to the second power unit (25) via the second reduction gear set (23).

4. The transmission (1) according to claim 3, wherein the transmission ratio of the first reduction gear set (13) is different from the transmission ratio of the second reduction gear set (23).

5. The transmission (1) according to any one of the preceding claims, wherein the first shiftable gear unit (10) includes a first gear engagement member (17) configured to select one of a first plurality of gears of the first shiftable gear unit (10), and wherein the second shiftable gear unit (20) includes a second gear engagement member (27) configured to select one of a second plurality of gears of the second shiftable gear unit (20), the second plurality of gears including the bypass gear.

6. The transmission (1) according to any one of the preceding claims further includes a main shaft (60) and a plurality of main gear sets (61, 62), each main gear set (61, 62) including a plurality of gears (61a, 61b, 62a, 62b), wherein the main shaft (60) is rotatably connected to or can be connected to the gears (61b, 62b) of the plurality of gears in each main gear set (61, 62) and the rotating portion of the auxiliary transmission device (30).

7. The transmission (1) according to claim 6, which is dependent on claim 5, further comprising a common countershaft (80) rotatably connected to a gear of a common gear set (81), wherein the common gear set (81) is one of the plurality of master gear sets (61, 62), wherein the first gear engagement member (17) is configured to selectively engage the first input shaft (11) to the common countershaft (80), and the second gear engagement member (27) is configured to selectively engage the second input shaft (21) to the common countershaft (80).

8. The transmission (1) according to claim 7, wherein the secondary shaft (80) is arranged between the first input shaft (11) and the second input shaft (21) such that the secondary shaft (80) is coaxial and aligned with at least one of the first input shaft (11) and the second input shaft (21).

9. The transmission (1) according to claims 5 to 8 further includes a bypass gear set (90) comprising a plurality of gears (90a, 90b), wherein the bypass gear set (90) is drivably connected to the output shaft (50), wherein in the bypass position, the second gear engagement member (27) is configured to rotatably connect the second input shaft (21) to the gear (90a) of the bypass gear set (90).

10. The transmission (1) according to any one of the preceding claims further includes a differential gear assembly (55) drivably connected to the output shaft (50) and corresponding drive shafts (51a, 51b) of the drive axle of the vehicle (100).

11. The transmission (1) according to any one of the preceding claims, wherein in the bypass state, the transmission ratio of the transmission (1) from the second input shaft (21) to the output shaft (50) is less than the transmission ratio of the highest gear in the set of low gears and greater than the transmission ratio of the lowest gear in the set of high gears.

12. The transmission (1) according to any one of the preceding claims, wherein the auxiliary transmission unit (30) comprises a planetary gear set (31), the planetary gear set (31) comprising a center gear (32), a planet carrier (33) carrying one or more planetary gears (34), and a ring gear (35). Optionally, the gear (90b) of the bypass gear set (90) is connected to or can be connected to the planet carrier (33) of the planetary gear set (31). Optionally, the central gear (32) of the planetary gear set (31) is drivably connected to the main shaft. Optionally, in the high-speed gear state of the auxiliary transmission device (30), the ring gear (35) of the planetary gear set (31) and the center gear (32) of the planetary gear set (31) are fixed to each other for common rotation. Optionally, in the low-speed state of the auxiliary transmission unit (30), the ring gear (35) of the planetary gear set (31) is connected to the fixed node (70) of the transmission (1). Optionally, the auxiliary transmission unit (30) includes an auxiliary transmission shifting member (38) for selecting the high-speed gear state and the low-speed gear state.

13. A powertrain system (2) for a vehicle (100) comprising a first power unit (15), a second power unit (25), and a transmission (1) according to any one of the preceding claims.

14. A vehicle (100) comprising the powertrain system according to claim 13.

15. A method for operating a transmission (1) according to any one of claims 1 to 12, comprising: - To operate the transmission (1) in one of the high-speed and low-speed states (S1), - Shift the transmission (1) to the bypass position (S2), and - When the transmission (1) is set to the bypass state, the auxiliary transmission device (30) is shifted from the high-speed state to the low-speed state (S3), and vice versa.

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