Transmission device of electric vehicle

Abstract

The invention relates to a transmission device of an electric vehicle. The transmission device comprises an input shaft and an output shaft; a first gear stage including a first gear wheel and a second gear wheel drivingly connected to each other; a first planetary gear set including a first sun gear, a first ring gear, and a first planet carrier, where the first sun gear and the first ring gear are rotatably connected to the second gear wheel of the first gear stage, and where the first planet carrier is rotatably connected to the output shaft; and a crawling unit including a plurality of gear members, the crawling unit being drivingly connectable between the first planetary gear set and the output shaft through a first clutch, wherein the first clutch is configured to rotationally connect one of the plurality of gear members of the crawling unit to one of the first planetary gear, the first planet carrier, or a fixed member of the transmission to cause the first ring gear to rotate in an opposite direction compared to a rotation direction of the first planet carrier.

Description

Technical Field

[0001] The present disclosure generally relates to vehicle transmissions. In particular aspects, the present disclosure relates to a transmission for an electric vehicle. The present disclosure may be applicable to heavy-duty vehicles such as trucks, buses, and construction equipment, among other types of vehicles. Although the present disclosure may be described with respect to a specific vehicle, the present disclosure is not limited to any particular vehicle. Background Art

[0002] Vehicle propulsion systems are constantly evolving to meet market demands. A particular concern is the reduction of environmentally harmful exhaust emissions. Consequently, vehicles propelled by electric traction motors are becoming increasingly popular, whether they are cars or heavy vehicles.

[0003] For automobiles, transmissions typically include a fixed ratio between the input and output shafts to provide the desired output torque and cruising speed. However, for heavy vehicles, due to the relatively large weight of these types of vehicles, the need for startability and suitable motor speeds necessitates a transmission capable of multiple gear states. For example, omitting the transmission for heavy vehicles would require the use of powerful and expensive electric traction motors.

[0004] Conventional transmissions for heavy vehicles are either bulky or fail to provide the desired functionality, such as insufficient deceleration during crawling. Therefore, there is a need for a compact transmission that can achieve the desired speed range and provide sufficiently high torque to the wheels during launch. Summary of the Invention

[0005] According to a first aspect of the present disclosure, a transmission for a vehicle is provided, the transmission comprising: an input shaft drivably connected to an electric traction motor and an output shaft drivably connected to a pair of wheels of the vehicle; a first gear stage comprising a first gear wheel and a second gear wheel drivingly connected to each other, the first gear wheel being rotationally connected to the input shaft; a first planetary gear set comprising a first sun gear, a first ring gear, and a first planet carrier carrying a first set of planetary gears, the first set of planetary gears meshingly engaged with the first ring gear and the first sun gear, wherein the first sun gear and the first ring gear are rotatably connected to the second gear wheel of the first gear stage, and wherein the first planet carrier is rotationally connected to the output shaft; and a crawler unit comprising a plurality of gear members drivably connectable between the first planetary gear set and the output shaft via a first clutch, wherein the first clutch is configured to rotationally connect one of the plurality of gear members of the crawler unit to the first planet gear, the first planet carrier, or one of the stationary members of the transmission to cause the first ring gear to rotate in a direction opposite to a direction of rotation of the first planet carrier.

[0006] A first aspect of the present disclosure may seek to at least partially alleviate the problem of bulky transmissions in order to achieve the desired functionality associated with heavy vehicle embodiments. Thus, a technical benefit may include providing a compact transmission that is capable of achieving a desired number of selectable gear ratios and is provided with a crawling unit having a large reduction in speed between the input shaft and the output shaft. The large reduction in speed enables large vehicles to be started from a standstill in an ideal manner. The inventors of the present invention have recognised that by providing the crawling unit with a first clutch, when the first clutch is engaged the first ring gear rotates in a direction opposite to the direction of rotation of the first planetary carrier, further increasing the reduction in speed between the input shaft and the output shaft. Thus, a technical benefit is that when the first clutch is engaged a high torque may be provided to the wheels of the vehicle during crawling.

[0007] In the following text and throughout the specification, the expressions "rotationally connected to" and "rotationally connected" should be interpreted as meaning that a component of the transmission is connected to another component of the transmission in such a way that the components rotate in the same direction and at the same speed. Therefore, when the components are rotationally connected to each other, they rotate in the same direction and at the same speed. Therefore, the expression "connectable" should be interpreted as being connectable via a clutch, so that the components are selectively connectable. In the above, when one of the multiple gear members of the crawler unit is rotationally connected to the fixed member, the gear member of the crawler unit is also fixed, which should be understood to fall within the scope of the definition of "rotationally connected to".

[0008] Furthermore, the phrases "drivingly connected to" and "drivably connected to" should be understood to mean that the two components are either directly connected to each other, i.e., the components rotate in the same direction and at the same speed, or are connected to each other via one or more gears therebetween. In the latter example, when the first component rotates, the second component also rotates at a ratio to the first component. The first and second components do not necessarily rotate in the same direction and at the same speed.

[0009] Optionally, in some examples, including at least one preferred example, the first gear stage is a reduction gear stage, wherein during operation of the transmission, the first gear wheel rotates at a higher speed than the second gear wheel. Technical benefits may include allowing the motor to rotate faster. The size of the motor is determined by the maximum torque it can produce. Therefore, a higher speed can compensate for lower torque levels, and the motor can be made smaller, which in turn reduces the cost of such a motor.

[0010] The first gear wheel and the second gear wheel may be arranged in meshing engagement with each other. Alternatively, one or more additional gear wheels may be provided between the first gear wheel and the second gear wheel.

[0011] Optionally, in some examples, including at least one preferred example, the first sun gear of the first planetary gear set can be rotationally connected to the second gear wheel of the first gear stage via a second clutch of the transmission. A technical benefit can include the first sun gear being rotationally connected to the second gear wheel for some gear states, but not being rotationally connected to the second gear wheel for other gear states.

[0012] Similar to the explanation of the definition of “rotationally connected to” above, the wording “rotatably connected to” should be interpreted so that the components of the transmission rotate in the same direction and at the same speed when connected to each other by the clutch, which in the specific example is the second clutch.

[0013] Optionally, in some examples, including at least one preferred example, the first ring gear of the first planetary gearset can be rotationally connected to the second gearwheel of the first gear stage via a third clutch of the transmission. A technical benefit can include the first ring gear being rotationally connected to the second gearwheel for some gear states, but not being rotationally connected to the second gearwheel for other gear states.

[0014] Optionally, in some examples, including at least one preferred example, the first ring gear of the first planetary gear set may be rotationally connected to the stationary member via the third clutch.

[0015] The third clutch should also be interpreted as being able to adopt a neutral position in which it is not connected to any of the second gear wheel of the first gear stage or the fixed member. In this case, the ring gear rotates without directly interacting with the second gear wheel or the fixed member.

[0016] By implementing the second and third clutches, the transmission can achieve three gear ratios. The fourth gear ratio is provided by the first clutch of the crawler unit.

[0017] Optionally, in some examples, including at least one preferred example, the crawling unit includes a second planetary gear set, and the multiple gear components of the crawling unit include a second sun gear, a second ring gear and a second planet carrier carrying a second set of planetary gears, and the second set of planetary gears are meshed with the second ring gear and the second sun gear.

[0018] Optionally, in some examples, including at least one preferred example, the second sun gear is rotationally connected to the first planet carrier.

[0019] Optionally, in some examples, including at least one preferred example, the second ring gear may be rotationally connected to the first ring gear via the first clutch of the crawler unit. Technical benefits include the opposite rotational directions of the ring gears providing a sufficiently large ratio between the second gear wheel and the first planet carrier. Furthermore, this allows a crawler gear state to be engaged at a large diameter, which results in lower loads on the gear teeth.

[0020] Optionally, in some examples, including at least one preferred example, the second planet carrier is rotationally connected to the fixed member of the transmission. Technical benefits may include that the planet carrier and its planet wheels are not affected by centrifugal loads.

[0021] Optionally, in some examples, including at least one preferred example, the second ring gear is rotationally connected to the first ring gear.

[0022] Optionally, in some examples, including at least one preferred example, the second planet carrier may be rotationally connected to the stationary member via the first clutch of the crawler unit.

[0023] Optionally, in some examples, including at least one preferred example, the second ring gear is rotationally connected to the first ring gear.

[0024] Optionally, in some examples, including at least one preferred example, the second planet carrier is rotationally connected to the stationary member.

[0025] Optionally, in some examples, including at least one preferred example, the second sun gear may be rotationally connected to the first planet carrier via the first clutch of the crawler unit.

[0026] Technical benefits may include that a crawler gear state may be engaged via the second sun gear. Thus, the second sun gear may be provided with a smaller diameter since it is not subject to high torque loads.

[0027] Optionally, in some examples, including at least one preferred example, the second ring gear is rotationally connected to the first planet carrier.

[0028] Optionally, in some examples, including at least one preferred example, the second planet carrier is rotationally connected to the stationary member.

[0029] Optionally, in some examples, including at least one preferred example, the second sun gear may be rotationally connected to the first ring gear via the first clutch of the crawler unit.

[0030] Technical benefits can include providing a greater rotation in the opposite direction for the first ring gear, which in turn produces a greater ratio between the second gear wheel and the output shaft. In addition, the second sun gear can be provided with a smaller diameter because it is not subject to high torque loads.

[0031] Optionally, in some examples, including at least one preferred example, the second sun gear is rotationally connected to the first ring gear.

[0032] Optionally, in some examples, including at least one preferred example, the second ring gear is rotationally connected to the first planet carrier.

[0033] Optionally, in some examples, including at least one preferred example, the second planet carrier may be rotationally connected to the stationary member via the first clutch of the crawler unit.

[0034] Technical benefits can include providing a greater rotation in the opposite direction for the first ring gear, which in turn produces a greater ratio between the second gear wheel and the output shaft. In addition, the second sun gear can be provided with a smaller diameter because it is not subject to high torque loads.

[0035] Optionally, in some examples, including at least one preferred example, the second sun gear is rotationally connected to the first ring gear.

[0036] Optionally, in some examples, including at least one preferred example, the second planet carrier is rotationally connected to the stationary member.

[0037] Optionally, in some examples, including at least one preferred example, the second ring gear may be rotationally connected to the first planet carrier via the first clutch of the crawler unit.

[0038] Technical benefits may include the ability to engage a crawl gear state at a large diameter, which provides lower loads on the gear teeth. Furthermore, since the second planet carrier is rotationally connected to the stationary member, the second planet carrier and its planet wheels will not be affected by centrifugal forces.

[0039] Optionally, in some examples, including at least one preferred example, the crawler unit includes a crawler gear stage, the crawler gear stage including a set of crawler gear wheels, the set of crawler gear wheels being drivably connected between the first planet carrier and the first ring gear via the first clutch of the crawler unit. The first clutch of the crawler unit may be positioned to rotationally connect the first gear wheel of the set of gear wheels to the first planet carrier. Optionally, the first clutch of the crawler unit may be positioned to rotationally connect the second and third gear wheels of the set of gear wheels to each other, wherein the second gear wheel is arranged in meshing engagement with the first gear wheel and the third gear wheel is rotationally connected to the first ring gear. As another alternative, the first clutch of the crawler unit may be positioned to rotationally connect the third gear wheel of the set of gear wheels to the first ring gear.

[0040] Technical benefits may include a greater freedom in selecting the ratio between the first ring gear and the output shaft, thereby simplifying the adaptation of the transmission to a specific application.

[0041] Furthermore, the first clutch may advantageously be a first dog clutch. Technical benefits may include lower power loss when the dog clutch is disengaged. The second clutch and the third clutch may also be a second dog clutch and a third dog clutch, respectively.

[0042] According to a second aspect, there is provided a driveline for an electric vehicle, the driveline comprising: an electric traction motor; and a transmission according to any one of the examples described above in relation to the first aspect, wherein the input shaft of the transmission is drivingly connected to the electric traction motor.

[0043] The effects and features of the second aspect are largely similar to those described above with respect to the first aspect.

[0044] According to a third aspect, there is provided a vehicle comprising a transmission according to any one of the examples described above in relation to the first aspect or a driveline according to the second aspect.

[0045] The effects and features of the third aspect are largely similar to those described above in relation to the first aspect.

[0046] The disclosed aspects, examples (including any preferred examples), and / or the appended claims may be appropriately combined with each other, as will be apparent to anyone skilled in the art. Additional features and advantages are disclosed in the following description, claims, and drawings, and in part will be apparent to those skilled in the art or recognized by practicing the disclosure as described herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Examples will be described in more detail below with reference to the accompanying drawings.

[0048] Figure 1 is an exemplary vehicle according to an example.

[0049] Figures 2 to 7 is a schematic diagram of an exemplary transmission, and

[0050] Figures 8 and 9 is a schematic diagram of an exemplary powertrain including a transmission. DETAILED DESCRIPTION

[0051] 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 the disclosure.

[0052] The following disclosure is directed to providing a compact and efficient transmission capable of achieving a desired number of gear ratios and providing a crawler unit with a large speed reduction between an input shaft and an output shaft.

[0053] First reference Figure 1 , which depicts an exemplary vehicle 10. The exemplary vehicle 10 is configured to be propelled at least in part by an electric traction motor 110. As will be apparent from the following description, and from Figures 2 to 9As can be seen in FIG, electric traction motor 110 is drivingly connected to transmission 120 , 220 , 320 , 420 , 520 , 620 , 720 .

[0054] To describe the transmission, reference is now made to Figure 2 , which depicts a first example of a transmission 120. The transmission 120 includes an input shaft 115. The input shaft 115 is drivingly connected to the electric traction motor 110. Figure 2 as well as Figures 3 to 9 In the example shown, the input shaft 115 is directly connected to the electric traction motor 110. However, it should be readily understood that there may be transmission components between the input shaft 115 and the electric traction motor 110, such as, for example, a clutch and / or a gear stage.

[0055] Furthermore, the transmission 120 comprises a first gear stage 130. The first gear stage 130 comprises a first gear wheel 131 and a second gear wheel 132 which are drivingly connected to each other. Preferably, the first gear stage 130 is a reduction gear stage, wherein during operation of the transmission, the first gear wheel 131 rotates at a higher speed than the second gear wheel 132. Figure 2 In the illustrated example, a first gear wheel 131 and a second gear wheel 132 are arranged in meshing engagement with one another. In this embodiment, the first gear wheel 131 includes a smaller number of gear teeth than the second gear wheel 132. However, it should be readily understood that one or more gear wheels may be positioned between the first gear wheel 131 and the second gear wheel 132. The first gear wheel 131 is rotationally connected to the input shaft 115, while the second gear wheel is rotationally connected to the transmission shaft 121 (also referred to as the inter-gearset shaft). The transmission shaft 121 is preferably hollow to accommodate the additional shaft 122.

[0056] The transmission 120 further includes a first planetary gear set 140 including a first sun gear 141 , a first ring gear 144 , and a first planet carrier 142 carrying a first set of planet gears 143 . The first set of planet gears 143 meshes with the first ring gear 144 and the first sun gear 141 .

[0057] In addition, the transmission device 120 further includes a creeping unit 150. The creeping unit 150 includes a plurality of gear members 151, 153, and 154. Figure 2 In the depicted example, the plurality of gear members are arranged as gear members of a second planetary gear set 160. The second planetary gear set 160 includes a second sun gear 151, a second ring gear 154, and a second planet carrier 152 carrying a second set of planet gears 153 in meshing engagement with the second ring gear 154 and the second sun gear 151.

[0058] In addition, the second sun gear 151 is rotationally connected to the first planet carrier 142. The second sun gear 151 is also rotationally connected to the output shaft 190 of the transmission 120, and the output shaft 190 is drivably connected to a pair of wheels of the vehicle, such as Figure 9 As can be seen, since the second sun gear 151 is rotationally connected to the first planet carrier 142 and the output shaft 190, the first planet carrier 142 is also rotationally connected to the output shaft 190. Furthermore, the second planet carrier 152 is rotationally connected to the stationary member 159 of the transmission 120. The stationary member 159 may be a transmission housing (not shown) that houses the transmission 120. By rotationally connecting the planet carrier 152 to the stationary member 159, the planet carrier 152 remains stationary for each gear state described below. Finally, the second ring gear 154 is rotationally connected to the first ring gear 144 via the first clutch 155 of the creeper unit 150. Thus, the first clutch 155 is configured to adopt a creeper engagement mode, in which the creeper unit 150 is drivingly connected to the first planetary gearset 140 by rotationally connecting the second ring gear 154 to the first ring gear 144. The first clutch 155 is also configured in a creep disengagement mode in which the creep unit 150 is disconnected from the first planetary gear set 140 by placing the first clutch 155 in a neutral position.

[0059] Turning again to the first planetary gearset 140, the first sun gear 141 of the first planetary gearset 140 is rotationally connected to the aforementioned additional shaft 122. The additional shaft 122 can be rotationally connected to the second gearwheel 132 of the first gear stage 130 via a second clutch 146. Thus, the first sun gear 141 can be rotationally connected to the second gearwheel 132 via the second clutch 146. The second clutch 146 is also configured to rotationally connect the first sun gear 141 to a stationary member 149a. Furthermore, the first ring gear 144 of the first planetary gearset 140 can be rotationally connected to the transmission shaft 121 via a third clutch 145. Thus, the third clutch 145 is configured to rotationally connect the first ring gear 144 to the second gearwheel 132 of the first gear stage 130. The third clutch 145 is also configured to rotationally connect the first ring gear 144 to the stationary member 149b. Furthermore, the third clutch 145 is also configured to adopt a neutral position in which the first ring gear 144 is non-rotatably connected to any one of the second gear wheel 132 and the fixed member 149 , ie, the first ring gear 144 freely rotates.

[0060] The aforementioned fixed member 149a connectable to the second clutch 146, the fixed member 149b connectable to the third clutch 145, and the fixed member rotatably connected to the second planet carrier 152 may be the same fixed member, such as, for example, the transmission housing. However, the fixed members may be formed from different transmission components as long as they are fixed relative to the rotating components to which they are connected or connectable.

[0061] Above about Figure 2 The depicted example describes a transmission 120 configured to employ three gear states (i.e., three different gear ratios) and a creeper gear. The first gear state is employed by positioning the first clutch 155 in a neutral position, positioning the second clutch 146 to rotationally connect the first sun gear 141 to the second gear wheel 132, and positioning the third clutch 145 to rotationally connect the first ring gear 144 to the stationary member 149b. As a result, the first ring gear 144 is stationary while the first sun gear 141 is driven, achieving a first speed reduction between the input and output shafts. The second gear wheel 132, the first sun gear 141, the first planet carrier 142, and the output shaft 190 all rotate in the same direction.

[0062] The second gear state is achieved by positioning first clutch 155 in a neutral position, second clutch 146 rotationally connecting first sun gear 141 to fixed member 149a, and third clutch 145 rotationally connecting first ring gear 144 to second gear wheel 132. As a result, first sun gear 141 is stationary while first ring gear 144 is driven, resulting in a second reduction in speed between the input and output shafts. This second reduction is lower / smaller than the first reduction. Second gear wheel 132, first ring gear 144, first planet carrier 142, and output shaft 190 all rotate in the same direction.

[0063] The third gear state is adopted by positioning the first clutch 155 in a neutral position, positioning the second clutch 146 to rotationally connect the first sun gear 141 to the second gear wheel 132, and positioning the third clutch 145 to rotationally connect the first ring gear 144 to the second gear wheel 132. Thus, a direct gear state is achieved in which the second gear wheel 132, the first sun gear 141, the first ring gear 144, the first planet carrier 142, and the output shaft 190 all rotate at the same speed and in the same direction.

[0064] A crawler gear is engaged by positioning first clutch 155 to rotationally connect second ring gear 154 to first ring gear 144, second clutch 146 to rotationally connect first sun gear 141 to second gearwheel 132, and third clutch 145 in a neutral position. This results in a third reduction between the input and output shafts, with first ring gear 144 and first planetary carrier 142 rotating in opposite directions. The third reduction is higher / greater than the first reduction. In other words, the output shaft rotates at a lower speed relative to the input shaft during the third reduction compared to the relative speeds of the input and output shafts during the first reduction. Second gearwheel 132, first sun gear 141, first planetary carrier 142, second sun gear 151, and output shaft 190 all rotate in the same direction, while first ring gear 144 and second ring gear 154 rotate in opposite directions.

[0065] To describe the transmission device 220 according to another example, refer to Figure 3 . Figure 2 The examples depicted in Figure 3 The difference between the examples depicted in FIG. 1 is the crawler unit and how it is connected to the first planetary gear set 140 and the stationary member. Figure 2 and Figure 3 The differences between the examples in .

[0066] exist Figure 3 In the example shown, the second ring gear 154 is rotationally connected to the first ring gear 144. The second planet carrier 152 may be rotationally connected to the stationary member 159 via a first clutch 155 of the creeper unit 150.

[0067] Figure 3 Transmission 220 in the depicted example is configured to employ three gear states (i.e., three different gear ratios) as well as a creeper gear. The first gear state is employed by positioning first clutch 155 in a neutral position, positioning second clutch 146 to rotationally connect first sun gear 141 to second gear wheel 132, and positioning third clutch 145 to rotationally connect first ring gear 144 to stationary member 149b. As a result, first ring gear 144 is stationary while first sun gear 141 is driven, achieving a first speed reduction between the input and output shafts.

[0068] The second gear state is adopted by positioning first clutch 155 in a neutral position, positioning second clutch 146 to rotationally connect first sun gear 141 to fixed member 149a, and positioning third clutch 145 to rotationally connect first ring gear 144 to second gear wheel 132. Thus, first sun gear 141 is stationary while first ring gear 144 is driven, resulting in a second reduction in speed between the input and output shafts. This second reduction is lower / smaller than the first reduction.

[0069] The third gear state is adopted by positioning the first clutch 155 in a neutral position, positioning the second clutch 146 to rotationally connect the first sun gear 141 to the second gear wheel 132, and positioning the third clutch 145 to rotationally connect the first ring gear 144 to the second gear wheel 132. Thus, a direct gear state is achieved in which the second gear wheel 132, the first sun gear 141, the first ring gear 144, the first planet carrier 142, and the output shaft 190 all rotate at the same speed and in the same direction. Figure 3 In the direct gear of the example shown, there is no relative rotation between the second sun gear 151 , the second planet carrier 152 , the second set of planetary gears 153 and the second ring gear 154 , which can reduce power loss.

[0070] A crawler gear is engaged by positioning first clutch 155 to rotationally connect second planet carrier gear 152 to stationary member 159, second clutch 146 to rotationally connect first sun gear 141 to second gear wheel 132, and third clutch 145 in a neutral position. This results in a third reduction in speed between the input and output shafts, with first ring gear 144 and first planet carrier 142 rotating in opposite directions. The third reduction is higher / greater than the first reduction. In other words, the output shaft rotates at a lower speed relative to the input shaft during the third reduction compared to the relative speed of the input and output shafts during the first reduction.

[0071] To describe the transmission device 320 according to another example, refer to Figure 4 . Figures 2 to 3 The examples depicted in Figure 4 The difference between the examples depicted in FIG is the crawler unit and how it is connected to the first planetary gear set 140 and the fixed member. Figures 2 to 3 The examples in Figure 4 The differences between the examples in .

[0072] exist Figure 4In the example shown, the second ring gear 154 is rotationally connected to the first ring gear 144. The second planet carrier 152 is rotationally connected to the fixed member 159, while the second sun gear 151 is rotationally connected to the first planet carrier 142 via the first clutch 155 of the creeper unit 150.

[0073] Figure 4 The transmission 320 in the depicted example is configured to employ three gear states (i.e., three different gear ratios) as well as a creeper gear. The first gear state is employed by positioning the first clutch 155 in a neutral position, positioning the second clutch 146 to rotationally connect the first sun gear 141 to the second gear wheel 132, and positioning the third clutch 145 to rotationally connect the first ring gear 144 to the stationary member 149b. As a result, the first ring gear 144 is stationary while the first sun gear 141 is driven, thereby achieving a first speed reduction between the input and output shafts.

[0074] The second gear state is adopted by positioning first clutch 155 in a neutral position, positioning second clutch 146 to rotationally connect first sun gear 141 to fixed member 149a, and positioning third clutch 145 to rotationally connect first ring gear 144 to second gear wheel 132. Thus, first sun gear 141 is stationary while first ring gear 144 is driven, resulting in a second reduction in speed between the input and output shafts. This second reduction is lower / smaller than the first reduction.

[0075] The third gear state is adopted by positioning the first clutch 155 in a neutral position, positioning the second clutch 146 to rotationally connect the first sun gear 141 to the second gear wheel 132, and positioning the third clutch 145 to rotationally connect the first ring gear 144 to the second gear wheel 132. Thus, a direct gear state is achieved in which the second gear wheel 132, the first ring gear 144, the first planet carrier 142, and the output shaft 190 all rotate in the same direction.

[0076] A crawler gear is engaged by positioning first clutch 155 to rotationally connect second sun gear 151 to first planetary carrier 142, second clutch 146 to rotationally connect first sun gear 141 to second gear wheel 132, and third clutch 145 in a neutral position. This results in a third reduction in speed between the input and output shafts, with first ring gear 144 and first planetary carrier 142 rotating in opposite directions. The third reduction is higher / greater than the first reduction. In other words, the output shaft rotates at a lower speed relative to the input shaft during the third reduction compared to the relative speed of the input and output shafts during the first reduction.

[0077] To describe the transmission device 420 according to another example, refer to Figure 5 . Figures 2 to 4 The examples depicted in Figure 5 The difference between the examples depicted in FIG is the crawler unit and how it is connected to the first planetary gear set 140 and the fixed member. Figures 2 to 4 The examples in Figure 5 The differences between the examples in .

[0078] exist Figure 5 In the example shown, the second sun gear 151 is rotationally connected to the first ring gear 144 via the first clutch 155. The second planet carrier 152 is rotationally connected to the fixed member 159. The second ring gear 154 is rotationally connected to the first planet carrier 142. Figure 2 As described above, the first planet carrier 142 is rotationally connected to the output shaft 190 , and the second ring gear 154 is also rotationally connected to the output shaft 190 .

[0079] Figure 5 The transmission 420 in the depicted example is configured to employ three gear states (i.e., three different gear ratios) as well as a creeper gear. The first gear state is employed by positioning the first clutch 155 in a neutral position, positioning the second clutch 146 to rotationally connect the first sun gear 141 to the second gear wheel 132, and positioning the third clutch 145 to rotationally connect the first ring gear 144 to the stationary member 149b. As a result, the first ring gear 144 is stationary while the first sun gear 141 is driven, thereby achieving a first speed reduction between the input and output shafts.

[0080] The second gear state is adopted by positioning first clutch 155 in a neutral position, positioning second clutch 146 to rotationally connect first sun gear 141 to fixed member 149a, and positioning third clutch 145 to rotationally connect first ring gear 144 to second gear wheel 132. Thus, first sun gear 141 is stationary while first ring gear 144 is driven, resulting in a second reduction in speed between the input and output shafts. This second reduction is lower / smaller than the first reduction.

[0081] The third gear state is adopted by positioning the first clutch 155 in a neutral position, positioning the second clutch 146 to rotationally connect the first sun gear 141 to the second gear wheel 132, and positioning the third clutch 145 to rotationally connect the first ring gear 144 to the second gear wheel 132. Thus, a direct gear state is achieved in which the second gear wheel 132, the first ring gear 144, the first planet carrier 142, and the output shaft 190 all rotate in the same direction.

[0082] A crawler gear is engaged by positioning first clutch 155 to rotationally connect second sun gear 151 to first ring gear 144, second clutch 146 to rotationally connect first sun gear 141 to second gearwheel 132, and third clutch 145 in a neutral position. This results in a third reduction in speed between the input and output shafts, with first ring gear 144 and first planetary carrier 142 rotating in opposite directions. The third reduction is higher / greater than the first reduction. In other words, the output shaft rotates at a lower speed relative to the input shaft during the third reduction compared to the relative speed of the input and output shafts during the first reduction.

[0083] To describe the transmission device 520 according to another example, refer to Figure 6 . Figures 2 to 5 The examples depicted in Figure 6 The difference between the examples depicted in FIG is the crawler unit and how it is connected to the first planetary gear set 140 and the fixed member. Figures 2 to 5 The examples in Figure 6 The differences between the examples in .

[0084] exist Figure 6 In the example shown, the second sun gear 151 is rotationally connected to the first ring gear 144. The second planet carrier 152 can be rotationally connected to the fixed member 159 via the first clutch 155 of the creeper unit 150. The second ring gear 154 is rotationally connected to the first planet carrier 142. Figure 2 As described above, the first planet carrier 142 is rotationally connected to the output shaft 190 , and the second ring gear 154 is also rotationally connected to the output shaft 190 .

[0085] Figure 6 The transmission 520 in the depicted example is configured to employ three gear states (i.e., three different gear ratios) as well as a creeper gear. The first gear state is employed by positioning the first clutch 155 in a neutral position, positioning the second clutch 146 to rotationally connect the first sun gear 141 to the second gear wheel 132, and positioning the third clutch 145 to rotationally connect the first ring gear 144 to the stationary member 149b. As a result, the first ring gear 144 is stationary while the first sun gear 141 is driven, thereby achieving a first speed reduction between the input and output shafts.

[0086] The second gear state is adopted by positioning first clutch 155 in a neutral position, positioning second clutch 146 to rotationally connect first sun gear 141 to fixed member 149a, and positioning third clutch 145 to rotationally connect first ring gear 144 to second gear wheel 132. Thus, first sun gear 141 is stationary while first ring gear 144 is driven, resulting in a second reduction in speed between the input and output shafts. This second reduction is lower / smaller than the first reduction.

[0087] The third gear state is adopted by positioning the first clutch 155 in a neutral position, positioning the second clutch 146 to rotationally connect the first sun gear 141 to the second gear wheel 132, and positioning the third clutch 145 to rotationally connect the first ring gear 144 to the second gear wheel 132. Thus, a direct gear state is achieved in which the second gear wheel 132, the first ring gear 144, the first planet carrier 142, and the output shaft 190 all rotate in the same direction.

[0088] A crawler gear is engaged by positioning first clutch 155 to rotationally connect second planet carrier 152 to stationary member 159, second clutch 146 to rotationally connect first sun gear 141 to second gear wheel 132, and third clutch 145 in a neutral position. This results in a third reduction in speed between the input and output shafts, with first ring gear 144 and first planet carrier 142 rotating in opposite directions. The third reduction is higher / greater than the first reduction. In other words, the output shaft rotates at a lower speed relative to the input shaft during the third reduction compared to the relative speed of the input and output shafts during the first reduction.

[0089] To describe the transmission device 620 according to another example, refer to Figure 7 . Figures 2 to 6 The examples depicted in Figure 7 The difference between the examples depicted in FIG is the crawler unit and how it is connected to the first planetary gear set 140 and the fixed member. Figures 2 to 6 The examples in Figure 7 The differences between the examples in .

[0090] exist Figure 7 In the example shown, the second sun gear 151 is rotationally connected to the first ring gear 144. The second planet carrier 152 is rotationally connected to the fixed member 159. The second ring gear 154 can be rotationally connected to the first planet carrier 142 via the first clutch 155 of the creeper unit 150. Figure 2As described above, the first planet carrier 142 is rotationally connected to the output shaft 190 , and the second ring gear 154 may also be rotationally connected to the output shaft 190 via the first clutch 155 .

[0091] Figure 7 Transmission 620 in the depicted example is configured to employ three gear states (i.e., three different gear ratios) as well as a creeper gear. The first gear state is employed by positioning first clutch 155 in a neutral position, positioning second clutch 146 to rotationally connect first sun gear 141 to second gear wheel 132, and positioning third clutch 145 to rotationally connect first ring gear 144 to stationary member 149b. As a result, first ring gear 144 is stationary while first sun gear 141 is driven, achieving a first speed reduction between the input and output shafts.

[0092] The second gear state is adopted by positioning first clutch 155 in a neutral position, positioning second clutch 146 to rotationally connect first sun gear 141 to fixed member 149a, and positioning third clutch 145 to rotationally connect first ring gear 144 to second gear wheel 132. Thus, first sun gear 141 is stationary while first ring gear 144 is driven, resulting in a second reduction in speed between the input and output shafts. This second reduction is lower / smaller than the first reduction.

[0093] The third gear state is adopted by positioning the first clutch 155 in a neutral position, positioning the second clutch 146 to rotationally connect the first sun gear 141 to the second gear wheel 132, and positioning the third clutch 145 to rotationally connect the first ring gear 144 to the second gear wheel 132. Thus, a direct gear state is achieved in which the second gear wheel 132, the first ring gear 144, the first planet carrier 142, and the output shaft 190 all rotate in the same direction.

[0094] A crawler gear is engaged by positioning first clutch 155 to rotationally connect second ring gear 154 to first planetary carrier 142, second clutch 146 to rotationally connect first sun gear 141 to second gearwheel 132, and third clutch 145 in a neutral position. This results in a third reduction in speed between the input and output shafts, with first ring gear 144 and first planetary carrier 142 rotating in opposite directions. The third reduction is higher / greater than the first reduction. In other words, the output shaft rotates at a lower speed relative to the input shaft during the third reduction compared to the relative speed of the input and output shafts during the first reduction.

[0095] To describe the transmission device 720 according to another example, refer to Figure 8 . and about Figures 2 to 7 In contrast to the depicted example, the crawler unit includes a crawler gear stage 760 instead of the aforementioned second planetary gear stage 160. The crawler gear stage 760 includes a set of crawler gear wheels 751, 753a, and 753b, which are drivably connected between the first planet carrier 142 and the first ring gear 144 via the first clutch 155 of the crawler unit 150. Specifically, the crawler unit 150 includes a first crawler gear wheel 751, which is rotationally connected to the first planet carrier 142 via the first clutch 155 of the crawler unit 150, and a second crawler gear wheel 753a, which is arranged to mesh with the first crawler gear wheel 751. The crawler unit 150 also includes a third crawler gear wheel 753b, which is rotationally connected to the second crawler gear wheel 753a via a crawler layshaft 752. The third crawler gear wheel 753b, in turn, meshes with the first ring gear 144 of the first planetary gear set 140. Alternatively, the crawler unit 150 may include a plurality of parallel crawler layshafts to drive-connect the first crawler gear wheel 751 to the first ring gear 144. In addition, the first clutch 155 may be arranged with the first clutch 155 in parallel. Figure 8 , such as between the second creeper gear wheel 753a and the third creeper gear wheel 753b.

[0096] Figure 8 The transmission 720 in the depicted example is configured to employ three gear states (i.e., three different gear ratios) as well as a creeper gear. The first gear state is employed by positioning the first clutch 155 in a neutral position, positioning the second clutch 146 to rotationally connect the first sun gear 141 to the second gear wheel 132, and positioning the third clutch 145 to rotationally connect the first ring gear 144 to the stationary member 149b. As a result, the first ring gear 144 is stationary while the first sun gear 141 is driven, thereby achieving a first speed reduction between the input and output shafts.

[0097] The second gear state is adopted by positioning first clutch 155 in a neutral position, positioning second clutch 146 to rotationally connect first sun gear 141 to fixed member 149a, and positioning third clutch 145 to rotationally connect first ring gear 144 to second gear wheel 132. Thus, first sun gear 141 is stationary while first ring gear 144 is driven, resulting in a second reduction in speed between the input and output shafts. This second reduction is lower / smaller than the first reduction.

[0098] The third gear state is adopted by positioning the first clutch 155 in a neutral position, positioning the second clutch 146 to rotationally connect the first sun gear 141 to the second gear wheel 132, and positioning the third clutch 145 to rotationally connect the first ring gear 144 to the second gear wheel 132. Thus, a direct gear state is achieved in which the second gear wheel 132, the first ring gear 144, the first planet carrier 142, and the output shaft 190 all rotate in the same direction.

[0099] A crawler gear is engaged by positioning the first clutch 155 so that the first crawler gear 751 is rotationally connected to the first planetary carrier 142. Since the first planetary carrier 142 is rotationally connected to the output shaft 190, the first crawler gear 751 is also rotationally connected to the output shaft 190. The second clutch 146 is positioned so that the first sun gear 141 is rotationally connected to the second gear wheel 132, and the third clutch 145 is positioned so that it adopts a neutral position. This results in a third reduction gearing between the input shaft and the output shaft, with the first ring gear 144 and the first planetary carrier 142 rotating in opposite directions. The third reduction gearing is higher / greater than the first reduction gearing. In other words, the output shaft rotates at a lower speed relative to the input shaft during the third reduction gearing compared to the relative speed of the input and output shafts during the first reduction gearing.

[0100] Final reference Figure 9 , which is a schematic diagram of an exemplary powertrain including a transmission. Figure 9 In the embodiment, the power transmission system 901 includes the above Figure 2 However, it should be readily understood that the transmission 120 described herein is Figures 3 to 8 Each of the exemplary transmissions described is also applicable to powertrain 901 .

[0101] Drivetrain 901 includes an electric traction motor 110 drivingly connected to an input shaft 115. Furthermore, drivetrain 901 includes a final drive 904, such as, for example, a bevel gear, drivingly connected to an output shaft 190. Final drive 904 is drivingly connected to a differential 902, which in turn is connected to wheels 906 of the vehicle. However, it should be readily understood that output shaft 190 could also be directly connected to differential 902 without the use of final drive 904.

[0102] Example List

[0103] Example 1: A transmission for a vehicle, the transmission comprising: an input shaft and an output shaft, the input shaft being drivably connected to an electric traction motor, the output shaft being drivably connected to a pair of wheels of the vehicle; a first gear stage, the first gear stage comprising a first gear wheel and a second gear wheel drivingly connected to each other, the first gear wheel being rotationally connected to the input shaft; a first planetary gear set, the first planetary gear set comprising a first sun gear, a first ring gear, and a first planet carrier carrying a first set of planetary gears, the first set of planetary gears being meshingly engaged with the first ring gear and the first sun gear, wherein the first sun gear and the first ring gear are rotatably connected to the second gear wheel of the first gear stage, and wherein the first planet carrier is rotationally connected to the output shaft; and a crawler unit comprising a plurality of gear members, the crawler unit being drivably connected between the first planetary gear set and the output shaft via a first clutch, wherein the first clutch is configured to rotationally connect one of the plurality of gear members of the crawler unit to the first planet gear, the first planet carrier, or one of the stationary members of the transmission, so as to cause the first ring gear to rotate in a direction opposite to a direction of rotation of the first planet carrier.

[0104] Example 2. The transmission according to example 1, wherein the first gear stage is a reduction gear stage, wherein during operation of the transmission, the first gear wheel rotates at a higher rotational speed than a rotational speed of the second gear wheel.

[0105] Example 3. The transmission according to any of examples 1 or 2, wherein the first sun gear of the first planetary gear set is rotationally connectable to the second gear wheel of the first gear stage via a second clutch of the transmission.

[0106] Example 4. A transmission according to any of the preceding examples, wherein the first ring gear of the first planetary gear set is rotationally connectable to the second gear wheel of the first gear stage via a third clutch of the transmission.

[0107] Example 5. The transmission of Example 4, wherein the first ring gear of the first planetary gear set is rotationally connectable to the stationary member via the third clutch.

[0108] Example 6. A transmission according to any one of the preceding examples, wherein the crawling unit includes a second planetary gear set, the plurality of gear members of the crawling unit including a second sun gear, a second ring gear and a second planet carrier carrying a second set of planetary gears, the second set of planetary gears being in meshing engagement with the second ring gear and the second sun gear.

[0109] Example 7. The transmission of Example 6, wherein the second sun gear is rotationally connected to the first planet carrier.

[0110] Example 8. The transmission of Example 7, wherein the second sun gear is rotationally connectable to the first ring gear via the first clutch of the crawler unit.

[0111] Example 9. A transmission according to any one of examples 7 or 8, wherein the second planet carrier is rotationally connected to the stationary member of the transmission.

[0112] Example 10. The transmission of Example 7, wherein the second ring gear is rotationally connected to the first ring gear.

[0113] Example 11. The transmission according to example 7 or 10, wherein the second planet carrier is rotationally connectable to the stationary member via the first clutch of the crawler unit.

[0114] Example 12. The transmission of Example 6, wherein the second ring gear is rotationally connected to the first ring gear.

[0115] Example 13. The transmission of example 6 or 12, wherein the second planet carrier is rotationally connected to the stationary member.

[0116] Example 14. The transmission of any one of Examples 6 or 12 to 13, wherein the second sun gear is rotatably connectable to the first planet carrier via the first clutch of the crawler unit.

[0117] Example 15. The transmission of Example 6, wherein the second ring gear is rotationally connected to the first planet carrier.

[0118] Example 16. The transmission of example 6 or 15, wherein the second planet carrier is rotationally connected to the stationary member.

[0119] Example 17. The transmission of any one of Examples 6 or 15 to 16, wherein the second sun gear is rotationally connectable to the first ring gear via the first clutch of the crawler unit.

[0120] Example 18. The transmission of Example 6, wherein the second sun gear is rotationally connected to the first ring gear.

[0121] Example 19. The transmission of example 6 or 18, wherein the second ring gear is rotationally connected to the first planet carrier.

[0122] Example 20. The transmission according to any one of Examples 6 or 18 to 19, wherein the second planet carrier is rotationally connectable to the stationary member via the first clutch of the crawler unit.

[0123] Example 21. The transmission of Example 6, wherein the second sun gear is rotationally connected to the first ring gear.

[0124] Example 22. The transmission of Example 6 or 21, wherein the second planet carrier is rotationally connected to the stationary member.

[0125] Example 23. The transmission of Examples 6 or 21-22, wherein the second sun gear is rotatably connected to the first planet carrier via the first clutch of the crawler unit.

[0126] Example 24. A transmission according to any one of Examples 1 to 5, wherein the crawler unit includes a crawler gear stage, the crawler gear stage including a set of crawler gear wheels, the set of crawler gear wheels being drivably connected between the first planet carrier and the first ring gear via the first clutch of the crawler unit.

[0127] Example 25. A powertrain for an electric vehicle, the powertrain comprising: an electric traction motor; and a transmission according to any of the preceding examples, wherein the input shaft of the transmission is drivingly connected to the electric traction motor.

[0128] Example 26. A vehicle comprising the transmission of any one of Examples 1 to 24, or the powertrain according to Example 25.

[0129] The terms used herein are for the purpose of describing specific aspects only and are not intended to limit the present disclosure. As used herein, unless the context clearly indicates otherwise, the singular forms "a", "an", and "the" 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 "include" and / or "comprising" when used herein indicate the presence of stated features, integers, actions, steps, operations, elements, and / or parts, but do not exclude the presence or addition of one or more other features, integers, actions, steps, operations, elements, parts, and / or groups thereof.

[0130] 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 only used to distinguish one element from another. For example, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element without departing from the scope of this disclosure.

[0131] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It should also be understood that, unless otherwise explicitly defined herein, the terms used herein should be interpreted as having the same meaning as in the context of this specification and the relevant art, and should not be interpreted in an idealized or overly formal sense.

[0132] It should be understood that the present disclosure is not limited to the aspects described above and shown in the accompanying drawings; rather, the skilled person will recognize that many changes and modifications may be made within the scope of the present disclosure and the appended claims. In the drawings and description, various aspects have been disclosed for illustrative purposes only and not for purposes of limitation, the scope of the disclosure being set forth in the appended claims.

Claims

1. A transmission device for a vehicle, the transmission device comprising: - an input shaft drivably connected to an electric traction motor and an output shaft drivably connected to a pair of wheels of the vehicle; - a first gear stage comprising a first gear wheel and a second gear wheel drivingly connected to each other, the first gear wheel being rotationally connected to the input shaft; - a first planetary gear set comprising a first sun gear, a first ring gear and a first planet carrier carrying a first set of planet gears, the first set of planet gears being in meshing engagement with the first ring gear and the first sun gear, wherein the first sun gear and the first ring gear are rotatably connected to the second gear wheel of the first gear stage, and wherein the first planet carrier is rotatably connected to the output shaft; as well as - a crawler unit comprising a plurality of gear members, the crawler unit being drivably connectable between the first planetary gear set and the output shaft via a first clutch, wherein the first clutch is configured to rotationally connect one of the plurality of gear members of the crawler unit to one of the first planetary gears, the first planet carrier, or a stationary member of the transmission so as to cause the first ring gear to rotate in a direction opposite to a direction of rotation of the first planet carrier. 2 . The transmission according to claim 1 , wherein the first gear stage is a reduction gear stage, wherein during operation of the transmission, the first gear wheel rotates at a higher rotational speed than the rotational speed of the second gear wheel. 3 . The transmission according to claim 1 , wherein the first sun gear of the first planetary gear set is rotationally connectable to the second gear wheel of the first gear stage via a second clutch of the transmission. 4 . The transmission according to claim 1 , wherein the first ring gear of the first planetary gear set is rotationally connectable to the second gear wheel of the first gear stage via a third clutch of the transmission. 5 . The transmission of claim 4 , wherein the first ring gear of the first planetary gear set is rotatably connected to the stationary member via the third clutch.

6. A transmission device according to any one of the preceding claims, wherein the crawling unit includes a second planetary gear set, the multiple gear members of the crawling unit including a second sun gear, a second ring gear and a second planet carrier carrying a second set of planet gears, and the second set of planet gears are in meshing engagement with the second ring gear and the second sun gear.

7. The transmission of claim 6, wherein the second sun gear is rotationally connected to the first planet carrier. 8 . The transmission according to claim 7 , wherein the second sun gear is rotatably connected to the first ring gear via the first clutch of the crawler unit.

9. A transmission according to any one of claims 7 or 8, wherein the second planet carrier is rotationally connected to the stationary member of the transmission.

10. The transmission of claim 7, wherein the second ring gear is rotationally connected to the first ring gear.

11. The transmission according to claim 7 or 10, wherein the second planet carrier is rotatably connected to the fixed member via the first clutch of the crawler unit.

12. The transmission of claim 6, wherein the second ring gear is rotationally connected to the first ring gear.

13. A transmission according to claim 6 or 12, wherein the second planet carrier is rotationally connected to the stationary member.

14. The transmission according to any one of claims 6 or 12 to 13, wherein the second sun gear is rotatably connected to the first planet carrier via the first clutch of the crawler unit.

15. The transmission of claim 6, wherein the second ring gear is rotationally connected to the first planet carrier.

16. A transmission according to claim 6 or 15, wherein the second planet carrier is rotationally connected to the stationary member.

17. The transmission according to any one of claims 6 or 15 to 16, wherein the second sun gear is rotationally connectable to the first ring gear via the first clutch of the crawler unit.

18. The transmission of claim 6, wherein the second sun gear is rotationally connected to the first ring gear.

19. A transmission according to claim 6 or 18, wherein the second ring gear is rotationally connected to the first planet carrier.

20. The transmission according to any one of claims 6 or 18 to 19, wherein the second planet carrier is rotationally connectable to the stationary member via the first clutch of the crawler unit.

21. The transmission of claim 6, wherein the second sun gear is rotationally connected to the first ring gear.

22. A transmission according to claim 6 or 21, wherein the second planet carrier is rotationally connected to the stationary member.

23. The transmission according to claim 6 or 21 to 22, wherein the second sun gear is rotatably connected to the first planet carrier via the first clutch of the crawler unit.

24. The transmission according to any one of claims 1 to 5, wherein the crawler unit comprises a crawler gear stage, the crawler gear stage comprising a set of crawler gear wheels, the set of crawler gear wheels being drivably connectable between the first planet carrier and the first ring gear via the first clutch of the crawler unit.

25. A power transmission system for an electric vehicle, the power transmission system comprising: - Electric traction motor, and - A transmission according to any one of the preceding claims, wherein the input shaft of the transmission is drivingly connected to the electric traction motor.

26. A vehicle comprising a transmission according to any one of claims 1 to 24, or a drivetrain according to claim 25.

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