Two-gear reduction device and vehicle having the same, control method of vehicle

Abstract

The application provides a two-gear speed reducer, a vehicle with the same and a control method of the vehicle. The two-gear speed reducer comprises an input shaft, a first intermediate shaft, a second intermediate shaft, a transition shaft, a differential and a multi-plate clutch. The input shaft is provided with a primary reduction driving gear. The first intermediate shaft is provided with a tertiary reduction driven gear and a main reduction driving gear. The second intermediate shaft is provided with a primary reduction driven gear, a secondary reduction driving gear and a synchronizer. The transition shaft is provided with a secondary reduction driven gear and a tertiary reduction driving gear. The secondary reduction driven gear is in mesh with the secondary reduction driving gear. The tertiary reduction driving gear is in mesh with the tertiary reduction driven gear. The driven end of the multi-plate clutch is fixedly connected with the first intermediate shaft. The passive end of the multi-plate clutch is fixedly connected with the second intermediate shaft. The housing of the differential is provided with a main reduction driven gear. The main reduction driven gear is in mesh with the main reduction driving gear. The scheme can realize a large first-gear speed ratio and improve the power performance of the vehicle.

Description

Technical Field

[0001] This invention relates to the field of vehicle design and manufacturing technology, and more specifically, to a two-speed reducer, a vehicle having the same, and a method for controlling the vehicle. Background Technology

[0002] In the pure electric vehicle sector, the vast majority of electric drive systems on the market currently consist of a drive motor and a single-speed reducer. On one hand, drive motors differ from traditional internal combustion engines in that they can provide high torque at low speeds and have a wider speed range. Therefore, complex multi-speed transmissions are no longer necessary; a drive motor and a single-speed reducer can meet the power and fuel economy requirements of most models. On the other hand, single-speed reducers offer advantages such as high transmission efficiency, low development difficulty, and low cost. With the rapid development of the electric vehicle market, customer demands for vehicle performance are increasing. For example, ordinary pure electric vehicles require reduced energy consumption at medium and high speeds to increase range; pure electric sports cars require higher acceleration and top speed; and large pure electric SUVs or pickup trucks require greater low-speed wheel-side torque. A single-speed reducer with a fixed transmission ratio can no longer meet the needs of all these operating conditions. A two-speed reducer, through two speed ratios, can effectively improve the overall power and fuel economy of the vehicle.

[0003] Currently, there are two main two-speed reducer solutions: The first is to add a pair of gears to a single-speed reducer to achieve a new gear. In this solution, the speed ratio of both gears is formed by two-stage reduction, which is relatively simple in structure and has high transmission efficiency. However, the speed ratio formed by two-stage reduction means that while ensuring a reasonable second gear ratio to meet the vehicle's economic needs, a larger center distance is needed to achieve a large first gear ratio (such as a first gear ratio of 15 or higher) to meet the vehicle's power requirements. However, the center distance is limited by the vehicle's layout space, so this solution is difficult to achieve a large first gear ratio in a limited space. The second solution is to add a planetary gear mechanism between the two-stage reduction gears to a single-speed reducer. By utilizing the characteristics of the planetary gear set and controlling the sun gear, planet gears, and ring gear, two speed ratios are formed. However, this solution is relatively complex in structure, and the use of a planetary gear mechanism also reduces transmission efficiency and NVH quality to some extent.

[0004] There is currently no effective solution to the aforementioned technical problem of not being able to achieve a larger gear ratio with a limited center distance. Summary of the Invention

[0005] The main objective of this invention is to provide a two-speed reducer, a vehicle having the same, and a vehicle control method, in order to solve the problem in the prior art that a larger gear ratio cannot be achieved with a limited center distance.

[0006] To achieve the above objectives, according to one aspect of the present invention, a two-speed reducer is provided, comprising: an input shaft, one end of which is connected to a drive unit, and a first-stage reduction drive gear is disposed on the input shaft, the first-stage reduction drive gear being coaxially and fixedly connected to the input shaft; a first intermediate shaft, on which a third-stage reduction driven gear and a main reduction drive gear are disposed, both the third-stage reduction driven gear and the main reduction drive gear being coaxially and fixedly connected to the first intermediate shaft; and a second intermediate shaft, sleeved outside the first intermediate shaft, on which a first-stage reduction driven gear, a second-stage reduction drive gear, and a synchronizer are disposed, the first-stage reduction driven gear meshing with the first-stage reduction drive gear, the second-stage reduction drive gear being loosely sleeved on the second intermediate shaft, and the synchronizer having a coupling with the second-stage reduction drive gear. The system includes: an engaged state of the first-stage reduction drive gear and a disengaged state of the second-stage reduction drive gear; a transition shaft with a second-stage reduction driven gear and a third-stage reduction drive gear mounted on it, both of which are coaxially and fixedly connected to the transition shaft; the second-stage reduction driven gear meshing with the second-stage reduction drive gear, and the third-stage reduction drive gear meshing with the third-stage reduction driven gear; a multi-plate clutch with its driven end fixedly connected to a first intermediate shaft and its driven end fixedly connected to a second intermediate shaft; and a differential with an output shaft, a main reduction driven gear mounted on its housing, coaxially and fixedly connected to the differential, and meshing with the main reduction drive gear.

[0007] Furthermore, the two-speed reducer also includes an overrunning clutch. The second intermediate shaft is connected to the second-stage reduction drive gear through the overrunning clutch. When the speed of the second intermediate shaft is greater than the speed of the second-stage reduction drive gear, the second intermediate shaft is connected to the second-stage reduction drive gear and rotates synchronously. When the speed of the second intermediate shaft is less than the speed of the second-stage reduction drive gear, the second intermediate shaft is disconnected from the second-stage reduction drive gear and rotates freely.

[0008] Furthermore, the transition shaft is sleeved outside the input shaft.

[0009] Furthermore, the input shaft is set parallel to the first intermediate shaft.

[0010] Furthermore, the transition axis is set parallel to the first intermediate axis.

[0011] According to another aspect of the present invention, a vehicle is provided having a two-speed reducer, which is the two-speed reducer described above.

[0012] According to another aspect of the present invention, a vehicle control method is provided. The method is used to control the vehicle described above. The method includes: controlling a multi-plate clutch to disengage, controlling a synchronizer to be engaged, and controlling an overrunning clutch to be engaged, so that the vehicle is in a first gear. In this method, power is transmitted sequentially along a first-stage reduction drive gear, a first-stage reduction driven gear, a second-stage reduction drive gear, a second-stage reduction driven gear, a third-stage reduction drive gear, a third-stage reduction driven gear, a main reduction drive gear, and a main reduction driven gear. The speed ratio of the two gear reducers is a first speed ratio.

[0013] Furthermore, the method also includes: controlling the engagement of the multi-plate clutch, controlling the synchronizer to be in a disengaged state, and controlling the overrunning clutch to be in a disengaged state, so that the vehicle is in the second gear, wherein the power is transmitted sequentially along the first-stage reduction drive gear, the first-stage reduction driven gear, the main reduction drive gear, and the main reduction driven gear, and the transmission ratio of the two-speed reducers is the second speed ratio.

[0014] Furthermore, the method also includes: controlling the multi-plate clutch to disengage, controlling the synchronizer to be in a disengaged state, controlling the overrunning clutch to be in a disengaged state, and disconnecting the connection between the first intermediate shaft and the second intermediate shaft to put the vehicle in neutral.

[0015] Furthermore, the method also includes: controlling the engagement of the multi-plate clutch, controlling the synchronizer to be engaged, controlling the overrunning clutch to be disengaged, and controlling the first intermediate shaft to be locked, so as to put the vehicle in the parking gear.

[0016] By applying the technical solution of this invention, four sets of transmission reduction gears (i.e., first-stage reduction driving gear and first-stage reduction driven gear, second-stage reduction driving gear and second-stage reduction driven gear, third-stage reduction driving gear and third-stage reduction driven gear, main reduction driving gear and main reduction driven gear) are set up to achieve four-stage transmission of the transmission ratio. Through reasonable speed ratio matching, a larger first-gear speed ratio can be achieved, solving the problem that the existing technology cannot achieve a larger first-gear speed ratio with a limited center distance, thus improving the vehicle's power performance. Attached Figure Description

[0017] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0018] Figure 1 A schematic diagram of the structure of a first embodiment of a two-speed reducer according to the present invention is shown;

[0019] Figure 2 A schematic diagram of a second embodiment of the two-speed reducer according to the present invention is shown.

[0020] The above figures include the following reference numerals:

[0021] 1. Input shaft; 2. Three-stage reduction drive gear; 3. Two-stage reduction driven gear; 4. Transition shaft; 5. One-stage reduction drive gear; 6. Multi-plate clutch; 7. One-stage reduction driven gear; 8. Synchronizer; 9. Two-stage reduction drive gear; 10. Three-stage reduction driven gear; 11. Second intermediate shaft; 12. Overrunning clutch; 13. First intermediate shaft; 14. Main reduction drive gear; 15. Main reduction driven gear; 16. Differential. Detailed Implementation

[0022] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0023] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0024] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of this application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0025] Exemplary embodiments according to this application will now be described in more detail with reference to the accompanying drawings. However, these exemplary embodiments may be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. It should be understood that these embodiments are provided so that the disclosure of this application is thorough and complete, and that the concept of these exemplary embodiments is fully conveyed to those skilled in the art. In the drawings, for clarity, the thickness of layers and regions may be exaggerated, and the same reference numerals are used to denote the same devices, and therefore their description will be omitted.

[0026] Combination Figures 1 to 2As shown, according to a specific embodiment of this application, a two-speed reducer is provided.

[0027] The two-speed reducer includes an input shaft 1, a first intermediate shaft 13, a second intermediate shaft 11, a transition shaft 4, a multi-plate clutch 6, and a differential 16. One end of the input shaft 1 is connected to the drive unit. A first-stage reduction drive gear 5 is mounted on the input shaft 1 and is coaxially and fixedly connected to the input shaft 1. A third-stage reduction driven gear 10 and a main reduction drive gear 14 are mounted on the first intermediate shaft 13 and are coaxially and fixedly connected to the first intermediate shaft 13. The second intermediate shaft 11 is sleeved outside the first intermediate shaft 13. A first-stage reduction driven gear 7, a second-stage reduction drive gear 9, and a synchronizer 8 are mounted on the second intermediate shaft 11. The first-stage reduction driven gear 7 meshes with the first-stage reduction drive gear 5, and the second-stage reduction drive gear 9 is loosely sleeved on the second intermediate shaft 11. The synchronizer... 8 has an engaged state connected to the second-stage reduction drive gear 9 and a disengaged state separated from the second-stage reduction drive gear 9; a second-stage reduction driven gear 3 and a third-stage reduction drive gear 2 are provided on the transition shaft 4, both of which are coaxially and fixedly connected to the transition shaft 4, the second-stage reduction driven gear 3 meshes with the second-stage reduction drive gear 9, and the third-stage reduction drive gear 2 meshes with the third-stage reduction driven gear 10; the driven end of the multi-plate clutch 6 is fixedly connected to the first intermediate shaft 13, and the driven end of the multi-plate clutch 6 is fixedly connected to the second intermediate shaft 11; the differential 16 has an output shaft, and a main reduction driven gear 15 is provided on the housing of the differential 16, which is coaxially and fixedly connected to the differential 16, and meshes with the main reduction drive gear 14.

[0028] By applying the technical solution of this embodiment, four sets of transmission reduction gears (i.e., first-stage reduction drive gear 5 and first-stage reduction driven gear 7, second-stage reduction drive gear 9 and second-stage reduction driven gear 3, third-stage reduction drive gear 2 and third-stage reduction driven gear 10, main reduction drive gear 14 and main reduction driven gear 15) are set up to achieve four-stage transmission of the transmission ratio. Through reasonable speed ratio matching, a larger first-gear ratio can be achieved, which solves the problem that the existing technology cannot achieve a larger first-gear ratio with a limited center distance, thereby improving the vehicle's power performance.

[0029] Furthermore, the two-speed reducer also includes an overrunning clutch 12. The second intermediate shaft 11 is connected to the second-stage reduction drive gear 9 via the overrunning clutch 12. When the rotational speed of the second intermediate shaft 11 is greater than that of the second-stage reduction drive gear 9, the second intermediate shaft 11 is connected to the second-stage reduction drive gear 9 and rotates synchronously. When the rotational speed of the second intermediate shaft 11 is less than that of the second-stage reduction drive gear 9, the second intermediate shaft 11 is disconnected from the second-stage reduction drive gear 9 and rotates freely. The overrunning clutch 12 ensures that the second intermediate shaft 11 and the second-stage reduction drive gear 9 are connected in a timely manner during gear shifting, allowing them to rotate synchronously. This avoids power interruption during gear shifting intervals (i.e., the gap between disengaging the multi-plate clutch 6 and engaging the synchronizer 8), maintaining continuous power input and more stable power output for the vehicle.

[0030] Furthermore, the transition shaft 4 is fitted outside the input shaft 1. For example... Figure 1 As shown, by setting the transition shaft 4 and the input shaft 1 as a coaxial nested structure, the two-speed reducer has a more compact structure and reduces the space occupied.

[0031] It should be noted that, as Figure 2 As shown, the transition axis 4 can also be set separately, that is, the transition axis 4 and the input axis 1 are not set in a coaxial nested configuration. The center distance between the transition axis 4 and the first intermediate axis 13 is not limited by the center distance between the input axis 1 and the first intermediate axis 13, making speed ratio matching easier.

[0032] Specifically, the input shaft 1 is arranged parallel to the first intermediate shaft 13. Arranging the input shaft 1 and the first intermediate shaft 13 in parallel allows for more orderly and efficient meshing between gears, more efficient power transmission, and a more compact structural design.

[0033] Specifically, the transition shaft 4 is arranged parallel to the first intermediate shaft 13. Arranging the transition shaft 4 and the first intermediate shaft 13 in parallel allows for more orderly and efficient meshing between gears, more efficient power transmission, and a more compact structural design.

[0034] According to another specific embodiment of this application, a vehicle is also provided, which has a two-speed reducer, the two-speed reducer described above. The vehicle in this embodiment is preferably a pure electric vehicle.

[0035] According to another specific embodiment of this application, a vehicle control method is also provided. The method is used to control the vehicle described above. The method includes: controlling the multi-plate clutch 6 to disengage, controlling the synchronizer 8 to be engaged, and controlling the overrunning clutch 12 to be engaged, so that the vehicle is in the first gear. In this method, power is transmitted sequentially along the first-stage reduction drive gear 5, the first-stage reduction driven gear 7, the second-stage reduction drive gear 9, the second-stage reduction driven gear 3, the third-stage reduction drive gear 2, the third-stage reduction driven gear 10, the main reduction drive gear 14, and the main reduction driven gear 15. The speed ratio of the two gear reducers is the first speed ratio.

[0036] Specifically, when the vehicle is in first gear, the transmission route is as follows: input shaft 1 → first-stage reduction drive gear 5 → first-stage reduction driven gear 7 → second intermediate shaft 11 → synchronizer 8 → second-stage reduction drive gear 9 → second-stage reduction driven gear 3 → third-stage reduction drive gear 2 → third-stage reduction driven gear 10 → first intermediate shaft 13 → main reduction drive gear 14 → main reduction driven gear 15 → differential 16. Power is transmitted through a four-stage gear set (i.e., first-stage reduction drive gear 5, first-stage reduction driven gear 7, second-stage reduction drive gear 9, second-stage reduction driven gear 3, third-stage reduction drive gear 2, third-stage reduction driven gear 10, main reduction drive gear 14, and main reduction driven gear 15). By setting the parameter values ​​of second-stage reduction drive gear 9, second-stage reduction driven gear 3, third-stage reduction drive gear 2, and third-stage reduction driven gear 10, a larger first gear ratio can be obtained.

[0037] Furthermore, the method also includes: controlling the multi-plate clutch 6 to engage, controlling the synchronizer 8 to disengage, and controlling the overrunning clutch 12 to disengage, so that the vehicle is in the second gear, wherein power is transmitted sequentially along the first-stage reduction drive gear 5, the first-stage reduction driven gear 7, the main reduction drive gear 14, and the main reduction driven gear 15, and the transmission ratio of the two gear reducers is the second gear ratio.

[0038] Specifically, when the vehicle is in second gear, the transmission route is as follows: input shaft 1 → first-stage reduction drive gear 5 → first-stage reduction driven gear 7 → second intermediate shaft 11 → multi-plate clutch 6 → first intermediate shaft 13 → main reduction drive gear 14 → main reduction driven gear 15 → differential 16. Power is transmitted through two gear sets (i.e., first-stage reduction drive gear 5, first-stage reduction driven gear 7, main reduction drive gear 14, and main reduction driven gear 15), achieving the standard second-gear setting of existing technology.

[0039] Furthermore, the method also includes: controlling the multi-plate clutch 6 to disengage, controlling the synchronizer 8 to be in a disengaged state, controlling the overrunning clutch 12 to be in a disengaged state, and disconnecting the connection between the first intermediate shaft 13 and the second intermediate shaft 11, so that the vehicle is in neutral. The neutral state is suitable for situations such as temporary vehicle parking, facilitating subsequent gear shifting when starting the vehicle.

[0040] Furthermore, the method also includes: controlling the multi-plate clutch 6 to engage, controlling the synchronizer 8 to be engaged, controlling the overrunning clutch 12 to be disengaged, and controlling the first intermediate shaft 13 to be locked, so that the vehicle is in the parking gear. When in the parking gear, the first intermediate shaft 13 is locked, which ensures that there is no power output at this time.

[0041] Specifically, in one exemplary embodiment of this application, the first-stage reduction drive gear 5 and the first-stage reduction driven gear 7 form a reduction ratio i1, the second-stage reduction drive gear 9 and the second-stage reduction driven gear 3 form a reduction ratio i2, the third-stage reduction drive gear 2 and the third-stage reduction driven gear 10 form a reduction ratio i3, and the main reduction drive gear 14 and the main reduction driven gear 15 form a reduction ratio i1. diff When the vehicle is in first gear, the transmission ratio is the first gear ratio i. 1st First speed ratio i 1st =i1×i2×i3×i diff When the vehicle is in second gear, the transmission ratio is the second gear ratio i. 2nd Second speed ratio i 2nd =i1×i diff .

[0042] Based on the above embodiments, the vehicle has four gears: first gear, second gear, neutral, and parking gear. The shifting logic is shown in Table 1 below.

[0043] Table 1:

[0044]

[0045] Note: In Table 1, “╳” indicates separation; “○” indicates joining.

[0046] Compared to existing technologies, vehicles using the two-speed reducer in the above embodiments have the following advantages over single-speed reducers: First-stage reduction gear set (i.e., first-stage reduction drive gear 5 and first-stage reduction driven gear 7, forming a reduction ratio i1) and main reduction gear set (i.e., main reduction drive gear 14 and main reduction driven gear 15, forming a reduction ratio i1). diff Between these two gear sets, two more parallel shaft gear sets are inserted to form two additional reduction ratios (i.e., the second-stage reduction driving gear 9 and the second-stage reduction driven gear 3 form reduction ratio i2, and the third-stage reduction driving gear 2 and the third-stage reduction driven gear 10 form reduction ratio i3). The original reduction ratio i1 and reduction ratio i diff This constitutes a second gear ratio; the original reduction ratio i1 and reduction ratio i diffThe first gear ratio is formed by two sequentially inserted reduction ratios (reduction ratio i2 and reduction ratio i3). (Choosing to insert two gear ratios instead of one solves the gear rotation problem.) The first gear ratio is formed by four reduction ratios. Through reasonable gear ratio matching, a larger first gear ratio (such as a first gear ratio of 15 or higher) can be achieved, solving the problem that existing technologies cannot achieve a larger first gear ratio with limited center distance. In addition, this structure has a multi-plate clutch 6, a synchronizer 8, and an overrunning clutch 12. Through the combined control of the separation and engagement of these components, the power switching between first gear, second gear, neutral, and parking gear can be realized (in addition, reverse gear can be achieved by reversing the drive motor).

[0047] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0048] In addition to the above, it should be noted that the terms "one embodiment," "another embodiment," and "embodiment" used in this specification refer to specific features, structures, or characteristics described in connection with that embodiment, which are included in at least one embodiment described in the general description of this application. The appearance of the same expression in multiple places in the specification does not necessarily refer to the same embodiment. Furthermore, when a specific feature, structure, or characteristic is described in connection with any embodiment, the intention is to suggest that implementing such a feature, structure, or characteristic in conjunction with other embodiments also falls within the scope of this invention.

[0049] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0050] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A two-speed reducer, characterized in that, include: An input shaft (1) is provided, one end of which is connected to a drive unit. A first-stage reduction drive gear (5) is provided on the input shaft (1), and the first-stage reduction drive gear (5) is coaxially and fixedly connected to the input shaft (1). A first intermediate shaft (13) is provided with a three-stage reduction driven gear (10) and a main reduction driving gear (14). The three-stage reduction driven gear (10) and the main reduction driving gear (14) are both coaxially fixedly connected to the first intermediate shaft (13). The second intermediate shaft (11) is sleeved outside the first intermediate shaft (13). The second intermediate shaft (11) is provided with a first-stage reduction driven gear (7), a second-stage reduction driving gear (9) and a synchronizer (8). The first-stage reduction driven gear (7) is meshed with the first-stage reduction driving gear (5). The second-stage reduction driving gear (9) is loosely sleeved on the second intermediate shaft (11). The synchronizer (8) has an engaged state connected to the second-stage reduction driving gear (9) and a disengaged state separated from the second-stage reduction driving gear (9). A transition shaft (4) is provided with a two-stage reduction driven gear (3) and a three-stage reduction driving gear (2). The two-stage reduction driven gear (3) and the three-stage reduction driving gear (2) are both coaxially fixedly connected to the transition shaft (4). The two-stage reduction driven gear (3) meshes with the two-stage reduction driving gear (9), and the three-stage reduction driving gear (2) meshes with the three-stage reduction driven gear (10). A multi-plate clutch (6), wherein the driven end of the multi-plate clutch (6) is fixedly connected to the first intermediate shaft (13), and the passive end of the multi-plate clutch (6) is fixedly connected to the second intermediate shaft (11); Differential (16), the differential (16) has an output shaft, and a main reduction driven gear (15) is provided on the housing of the differential (16). The main reduction driven gear (15) is coaxially fixedly connected to the differential (16), and the main reduction driven gear (15) is meshed with the main reduction driving gear (14). The two-speed reducer also includes an overrunning clutch (12). The second intermediate shaft (11) is connected to the second-stage reduction drive gear (9) through the overrunning clutch (12). When the rotational speed of the second intermediate shaft (11) is greater than the rotational speed of the second-stage reduction drive gear (9), the second intermediate shaft (11) is connected to the second-stage reduction drive gear (9) and rotates synchronously. When the rotational speed of the second intermediate shaft (11) is less than the rotational speed of the second-stage reduction drive gear (9), the second intermediate shaft (11) is disconnected from the second-stage reduction drive gear (9) and rotates freely.

2. The two-speed reducer according to claim 1, characterized in that, The transition shaft (4) is sleeved outside the input shaft (1).

3. The two-speed reducer according to claim 1, characterized in that, The input shaft (1) is arranged parallel to the first intermediate shaft (13).

4. The two-speed reducer according to claim 1, characterized in that, The transition shaft (4) is arranged parallel to the first intermediate shaft (13).

5. A vehicle having a two-speed reducer, characterized in that, The two-speed reducer is the two-speed reducer according to any one of claims 1-4.

6. A method for controlling a vehicle, said method for controlling the vehicle of claim 5, characterized in that, The method includes: The multi-plate clutch (6) is controlled to disengage, the synchronizer (8) is controlled to be in the engaged state, and the overrunning clutch (12) is controlled to be in the engaged state, so that the vehicle is in the first gear. The power is transmitted sequentially along the first-stage reduction drive gear (5), the first-stage reduction driven gear (7), the second-stage reduction drive gear (9), the second-stage reduction driven gear (3), the third-stage reduction drive gear (2), the third-stage reduction driven gear (10), the main reduction drive gear (14), and the main reduction driven gear (15). The transmission ratio of the two-speed reducer is the first speed ratio.

7. The method according to claim 6, characterized in that, The method further includes: The multi-plate clutch (6) is engaged, the synchronizer (8) is disengaged, and the overrunning clutch (12) is disengaged, so that the vehicle is in the second gear. Power is transmitted sequentially along the first-stage reduction drive gear (5), the first-stage reduction driven gear (7), the main reduction drive gear (14), and the main reduction driven gear (15). The transmission ratio of the two-speed reducer is the second speed ratio.

8. The method according to claim 6, characterized in that, The method further includes: Control the multi-plate clutch (6) to disengage, control the synchronizer (8) to be in the disengaged state, control the overrunning clutch (12) to be in the disengaged state, and disconnect the first intermediate shaft (13) from the second intermediate shaft (11) so that the vehicle is in neutral.

9. The method according to claim 6, characterized in that, The method further includes: The multi-plate clutch (6) is engaged, the synchronizer (8) is engaged, the overrunning clutch (12) is disengaged, and the first intermediate shaft (13) is locked, so that the vehicle is in parking gear.

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