Amphibious vehicle and hybrid transmission structure thereof

Abstract

The present application provides an amphibious vehicle and a hybrid transmission structure thereof, which are applied to the technical field of amphibious vehicles. The hybrid transmission structure of the amphibious vehicle includes: a locker, a first clutch, a second clutch, a third clutch, a first coupler and a second coupler. The locker, the clutch and the coupler cooperate with each other to provide power during driving on water or on land, thereby solving the hybrid problem of the amphibious vehicle.

Description

Technical Field

[0001] The present application relates to the technical field of vehicle transmissions, and in particular to an amphibious vehicle and a hybrid transmission structure thereof. Background Art

[0002] Existing amphibious vehicles use a single engine as a power source, but the engine's power characteristics make it difficult to balance the power requirements of water travel with fuel economy on land. In addition, a dual-engine layout not only increases the vehicle's weight but also makes it more difficult to locate the vehicle's center of gravity.

[0003] Based on this, a new power supply solution is needed for amphibious vehicles. Summary of the Invention

[0004] In view of this, the present application provides an amphibious vehicle and a hybrid transmission structure thereof to solve the problem of current amphibious vehicles using hybrid power.

[0005] The embodiments of this specification provide the following technical solutions:

[0006] The embodiment of this specification provides an amphibious vehicle hybrid transmission structure, including: a locker, a first clutch, a second clutch, a third clutch, a first adapter and a second adapter;

[0007] When in pure electric mode for water travel, the second clutch is in a closed state, and the first clutch, the third clutch, and the lock are all in a disengaged state. The closing of the second clutch allows the first motor to drive the jet engine through the closed second clutch to propel the vehicle on the water.

[0008] When in hybrid mode for water travel, the detent and second clutch are both in the closed state, and the first and third clutches are both in the open state. The closing of the second clutch allows the first motor to drive the jet engine through the closed second clutch to propel the vehicle on the water. The closing of the detent causes the second motor to rotate forward, pulling the engine to work. The engine cooperates with the second motor to generate electricity as an auxiliary power unit.

[0009] When in pure electric mode for land travel, the first clutch is in a closed state, and the second clutch, the third clutch, and the lock are all in a disengaged state. The closing of the first clutch enables the first motor to drive the vehicle on land through the closed first clutch and the second clutch.

[0010] When the hybrid mode is used for land driving, the locker and the first clutch are both in the closed state, and the second clutch and the third clutch are both in the disconnected state; wherein, the closing of the locker causes the second motor to rotate forward to drag the engine to work, and the engine cooperates with the second motor as an auxiliary power unit to generate electricity; when in series hybrid, the closing of the first clutch causes the first motor to drive the vehicle on land through the closed first clutch and the second coupler; when in parallel hybrid, the closing of the first clutch causes the first motor to drive the vehicle on land through the closed first clutch and the second coupler, and the second motor and the engine drive the vehicle on land through the first coupler.

[0011] Preferably, in the hybrid mode for water travel, when the state of charge of the battery is lower than a preset condition, the closing of the lock causes the second motor to rotate forward to start the engine to work as an auxiliary power unit to supply power to the battery, wherein the planetary gear set acts as a reduction mechanism.

[0012] Preferably, in the hybrid mode for water travel, the lock is closed so that the second motor rotates forward to start the engine, and then the lock is disconnected to indirectly control the speed of the sun gear by controlling the speed of the second motor and the engine, and when the speed of the sun gear is the same as the speed of the first motor, the third clutch is closed to adjust the engine speed by controlling the speed of the second motor when the speed of the sun gear is constant, and at the same time, by controlling the torque of the first motor, the engine torque can be adjusted when the speeds of the sun gear, ring gear and planetary carrier are fixed.

[0013] Preferably, when used in the water-land switching mode, the lock and the second clutch are in the closed state, and the first clutch and the third clutch are in the disconnected state; wherein, the closing of the lock enables the second motor to rotate forward to start the engine and then drive the vehicle through the first clutch, and the closing of the second clutch enables the first motor to drive the jet engine through the closed second clutch to propel the vehicle on the water.

[0014] Preferably, in a parallel hybrid, when the lock is switched from closed to open, the third clutch is switched from open to closed, so that the first motor is connected to the sun gear of the planetary gear set through the third clutch, and the second motor drives the ring gear of the planetary gear set, the engine drives the planetary carrier of the planetary gear set, and drives the vehicle through the third clutch.

[0015] Preferably, the first clutch is used for engagement and switching between the first-speed gear set and the third-speed gear set, and the second clutch is used for engagement and switching between the second-speed gear set and the fourth-speed gear set.

[0016] An embodiment of this specification also provides an amphibious vehicle, comprising the amphibious vehicle hybrid transmission structure described in any embodiment of this specification.

[0017] Compared with the prior art, the at least one technical solution adopted in the embodiments of this specification can achieve the following beneficial effects:

[0018] 1. By using this hybrid transmission, amphibious vehicles can achieve pure electric mode and hybrid mode on both water and land, and switch between the two modes during driving. Due to the presence of batteries and motors, in hybrid mode, the engine operating point can be relatively decoupled from the load, and the engine operates in the high-efficiency range;

[0019] 2. Due to the presence of the motor, the response speed of the power unit to power requests is greatly improved. During vehicle acceleration, the speed regulation of the motor reduces the shift shock and increases the gearbox shift speed;

[0020] 3. Under stable driving conditions, the engine is fixed in the high-efficiency working range through the motor and planetary gears, and the gear set is used for transmission to improve transmission efficiency;

[0021] 4. During the water-land switching process, this gearbox can realize the coordinated control of the water and land drive devices, improve the vehicle's entry and exit efficiency, and greatly shorten the entry and exit time. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0023] Figure 1 It is a structural diagram of the hybrid transmission structure of the amphibious vehicle in this application. DETAILED DESCRIPTION

[0024] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0025] The following describes the embodiments of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, in the absence of conflict, the features in the following embodiments and embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of this application.

[0026] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on this application, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number and aspect described herein can be used to implement an apparatus and / or practice a method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this apparatus and / or practice this method.

[0027] It should also be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present application. The illustrations only show components related to the present application and are not drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component can be changed at will, and the component layout type may also be more complicated.

[0028] Additionally, in the following description, specific details are provided to provide a thorough understanding of the examples, however, one skilled in the art will appreciate that the examples can be practiced without these specific details.

[0029] The following is an illustrative description of the gearbox structure in an amphibious vehicle, taking driving on water and driving on land as examples.

[0030] 1. Traveling on water

[0031] 1. Pure electric mode

[0032] When the vehicle battery SoC (State of Charge) is within the permitted range, the second clutch K2 is engaged, the first clutch K1, the third clutch K3, and the lock L are all disengaged, and the first electric motor EM1 drives the jet engine JET through the second clutch K2 to propel the vehicle on the water. At this time, the engine ICE and the second electric motor EM2 are both inoperative.

[0033] 2. Switch from pure electric mode to hybrid mode

[0034] In one example, when the battery SoC of the vehicle is too low in pure electric mode, the lock L and the second clutch are closed, and the first clutch K1 and the third clutch K3 are opened. The closing of the lock L causes the second electric motor EM2 to rotate forward and pull the engine ICE. At this time, the ICE + EM2 function as an Auxiliary Power Unit (APU) to supply power to the vehicle and the battery, and the planetary gear set functions as a reduction gear.

[0035] In one example, when a high power demand is encountered in pure electric mode, the lock L engages. The second electric motor (EM2) rotates forward to pull the engine (ICE). Then, the lock L disengages. By controlling the speeds of the second electric motor (EM2) and the engine (ICE), the speed of the sun gear (Sun) of the planetary gearset is indirectly controlled, rapidly approaching that of the first electric motor (EM1). Simultaneously, the third clutch (K3) engages. At this point, the second and third clutches (K2 and K3) engage, while the first clutch (K1) and the lock L disengage. The engine (ICE) and the second electric motor (EM2) are power-coupled via the planetary gear mechanism, with the torque of the first electric motor (EM1) superimposed on the speed of the sun gear (Sun). While maintaining a constant vehicle speed (Sun speed), controlling the speed of EM2 adjusts the ICE speed. Simultaneously, controlling the torque of EM1 adjusts the ICE torque while maintaining the speeds of the sun gear (Sun), ring gear (Ring), and carrier (Carrier) of the planetary gearset. This achieves complete decoupling (speed and torque) of the engine operating point from the load condition, enabling the engine to operate within its high-efficiency range.

[0036] 2. Water-land switching

[0037] During entry or exit, the first electric motor (EM1) drives the jet through the second clutch (K2) to propel the vehicle, while the ICE (ICE) and EM2 drive the wheels in 1st (3rd) gear. At this point, the first and third clutches (K1, K3) are disengaged, while the lock (L) and second clutch (K2) are engaged.

[0038] Due to the fluid-loading characteristics of the jet, at a constant speed, the jet load and fluid density are positively correlated. That is, at the same speed, the jet load (power) in water and air differs. Therefore, during both entry and exit, the jet only needs to maintain closed-loop control of the EM1 speed, with its output power automatically matched to the load. Furthermore, wheel driving force is determined by wheel slip. Maximum driving force under varying adhesion conditions occurs within the same slip range. Therefore, wheel (Sun) speed can be controlled by adjusting the EM2 and ICE speeds to maintain the wheel slip within a certain range, ensuring the highest possible driving force at all times. This allows the vehicle to simultaneously pass through the water, maximizing driving force on the ground to improve both entry and exit efficiency, significantly improving the time it takes to transition from water to road.

[0039] 3. Driving on land

[0040] 1. Pure electric mode

[0041] When the vehicle battery SoC is within the permitted range, the first electric motor EM1 drives the vehicle via the first clutch K1. The vehicle can be driven in second gear at low speeds and in fourth gear at medium speeds. Gear shifting adjusts the motor operating point to the high-efficiency range. At this point, the first clutch K1 is engaged, the lock L, the second clutch K2, and the third clutch K3 are disengaged, and the engine ICE and electric motor EM2 are inoperative.

[0042] 2. Switch from pure electric mode to hybrid mode

[0043] In pure electric mode, when the battery SoC is too low, the lock L engages, and the second electric motor EM2 rotates forward to pull the engine ICE. At this point, the lock L and the first clutch K1 engage, while the second clutch K2 and the third clutch K3 disengage. When the vehicle is at medium or low speeds, the ICE + EM2 function as the APU to supply power to the battery pack and electric motor EM1, which then drives the vehicle in gears 2 and 4, achieving series hybrid operation.

[0044] In pure electric mode, when a high power demand or high vehicle speed occurs, the immobilizer L engages, and the second electric motor (EM2) rotates forward, pulling the engine (ICE). At this point, the immobilizer L and the first clutch (K1) engage, while the second and third clutches (K2 and K3) disengage. The first electric motor (EM1) drives the vehicle through gears 2 / 4 via K1, while the ICE and EM2 simultaneously drive the vehicle through gears 1 / 3, achieving parallel hybrid operation.

[0045] 3. Series hybrid and parallel hybrid

[0046] Series hybrids are relatively simple, with the second clutch S2 shifting between 2nd and 4th gears depending on vehicle speed. In parallel hybrid mode, EM1 and ICE+EM2 act as two independent power sources, driving the vehicle through odd and even gears, respectively, with only one power unit driving the vehicle at a time through the corresponding clutch.

[0047] During the vehicle speed change, if the power unit currently engaged with and driving the wheel (WHEEL) is not operating in the optimal working range, the other power unit controls the motor speed to make the output gear speed of the gear set to be engaged close to the output shaft. The current clutch is disconnected from the output gear set while the other clutch is engaged. The entire gear shifting process has little impact and no power interruption.

[0048] In one example, when the vehicle is parked, the lock L is engaged, the first to third clutches (i.e., K1, K2, K3) are disengaged, and the first to second clutches (i.e., S1, S2) are both disengaged. At this time, the ICE+EM2 acts as an APU to supply power to the battery pack.

[0049] In one example, when the vehicle is starting and traveling at low speed, the first clutch S1 engages the first-gear gearset, and the ICE and EM2 drive the vehicle via the planetary gearset and the first-gear gearset. At this point, the lock L is engaged, the three clutches (i.e., K1, K2, and K3) are disengaged, and the planetary gearset acts as a speed reduction mechanism. The second electric motor EM2 can adjust the load on the engine ICE based on the load request and the SoC status.

[0050] In one example, as the vehicle speed increases, the first electric motor EM1 adjusts its speed via the first clutch K1 so that the output gear of the second gear set rotates at a speed close to that of the output shaft. Simultaneously, the first clutch S1 disengages the first gear, while the second clutch S2 engages the second gear. At this point, the lock L and first clutch K1 engage, while the second and third clutches K2 and K3 disengage. The first electric motor EM1 drives the vehicle in second gear, while the ICE + EM2 function as an APU, supplying power to the battery pack and EM1.

[0051] In one example, as the vehicle speed continues to increase, the EM2+ICE adjusts the speed so that the output gear of the 3rd gear set is close to the output shaft speed. Simultaneously, the first clutch S1 engages the 3rd gear, and the second clutch S2 disengages the 2nd gear. At this point, the lock L closes, the three clutches (i.e., K1, K2, and K3) disengage, and the ICE+EM2 drives the vehicle in 3rd gear via the planetary gear set.

[0052] In one example, as the vehicle speed continues to increase, the first electric motor EM1 is adjusted by the first clutch K1 so that the output gear of the fourth-speed gear set has a speed close to that of the output shaft. Simultaneously, the second clutch S2 engages the fourth-speed gear, while the first clutch S1 disengages the third-speed gear. At this point, the lock L and first clutch K1 are closed, while the second clutch K2 and third clutch K3 are disengaged, allowing the first electric motor EM1 to drive the vehicle in fourth gear.

[0053] It should be noted that the principle of vehicle deceleration and downshifting is similar to the above example and will not be elaborated here.

[0054] Furthermore, during parallel hybrid driving, if the vehicle accelerates suddenly or the driver selects power priority, the lock L disengages and the third clutch K3 engages. The first electric motor EM1 is coupled to the sun gear of the planetary gear set via the third clutch K3. The carrier and sun gear components of the planetary gear set engage in different gears via the first clutch K1 and the third clutch K3 through the corresponding first clutch S1 and second clutch S2. The speed between the carrier and sun gear is determined by the currently engaged gear. Therefore, different gear combinations of S1 and S2 enable different speed ratios to be achieved between components of the planetary gear set, such as the planet carrier (also referred to as carrier) and sun gear. As a result, the first electric motor EM1, the second electric motor EM2, and the engine ICE can simultaneously provide power to the vehicle via the first clutch S1 (odd-numbered gears) and the second clutch S2 (even-numbered gears). At this time, the first clutch K1 and the third clutch K3 are closed, the second clutch K2 and the lock L are disengaged, the second electric motor EM2 is connected through the ring gear Ring, the engine ICE is connected through the planetary carrier Carrier, and the first electric motor EM1 is connected to Sun through the third clutch K3. Since the output is simultaneously transmitted through two adapters (i.e., S1 and S2) through two sets of gear sets, and the three are linked by clutch and gear meshing and have a fixed speed relationship, it is equivalent to the first electric motor EM1, the second electric motor EM2, and the engine ICE outputting to the vehicle through a speed regulation mechanism. Compared with the acceleration process without gear meshing and separately controlling the speeds of EM1, EM2, and ICE, the upper limit of the transmission's output torque is greatly increased, thereby improving acceleration performance.

[0055] In one example, when the vehicle starts, the second clutch S2 is engaged in 2nd gear, the first clutch S1 is engaged in 1st gear, the first clutch K1 and the third clutch K3 are closed, and the second clutch K2 and the lock L are disengaged. The Sun, Carrier, and Ring speeds of the planetary gearset are fixed in ratio. Driven by the first electric motor EM1, the engine ICE, and the second electric motor EM2, respectively, the three motors are driven by the first and second gearsets, respectively. EM1, EM2, and the ICE rotate in this ratio, and torque is added to propel the vehicle. At this point, the second electric motor EM2 drives the vehicle through the first gearset, while the first electric motor EM1 drives the vehicle through the second gearset. Both have a single output shaft. Therefore, the ratio of the second electric motor EM2 speed to the first electric motor EM1 speed is I1 / I2. The engine ICE speed is determined by the size of the planetary gearset; the second electric motor EM2 speed is greater than the engine ICE speed, which is greater than the first electric motor EM1 speed. During vehicle acceleration, the speeds of the three motors maintain this ratio and increase.

[0056] In one example, as the vehicle accelerates, when the speed relationship defined by the 1st and 2nd gear sets no longer fits the operating range of the first electric motor (EM1), the second electric motor (EM2), and the engine (ICE), the first clutch (S1) disengages from 1st gear. While the first electric motor (EM1) maintains vehicle acceleration via the 2nd gear set, the speed of the second electric motor (EM2) and the engine (ICE) is controlled to bring the output gear of the 3rd gear set close to the output shaft, and the first clutch (S1) engages in 3rd gear. At this point, the Sun, Carrier, and Ring (EM1, ICE, and EM2) of the planetary gear set determine the speed ratio, defined by the 2nd and 3rd gear sets. The speed ratio of EM1, EM2, and ICE is fixed, and torque is superimposed to propel the vehicle. When the second clutch (S2) engages with the 2nd gear set and the first clutch (S1) engages with the 3rd gear set, the second electric motor (EM2) drives the vehicle via the 3rd gear set, while the first electric motor (EM1) drives the vehicle via the 2nd gear set, with a single output shaft.

[0057] Therefore, the ratio of EM2 speed to EM1 speed is I3 / I2. The ICE speed is determined by the size of the planetary gearset, so EM2 speed is lower than the ICE speed, which is lower than EM1 speed. In other words, after S1 disengages from first gear, EM1 continues to accelerate to maintain vehicle acceleration while simultaneously controlling the speed of EM2 to decrease. The ICE (whose speed is determined by the planetary gearset) stops injecting fuel. When EM2 speed drops to a speed similar to that of the output gear of the third gearset and the output shaft, S1 engages third gear.

[0058] It can be seen that at this time, the ICE speed drops compared to before switching from 1st gear to 3rd gear. Therefore, during the entire acceleration process, the engine's maximum torque platform can be utilized as much as possible to improve acceleration performance.

[0059] In one example, as the vehicle continues to accelerate, when the speed relationship defined by the 2nd and 3rd gear sets no longer fits the operating range of EM1, EM2, and the ICE, S2 disengages from 2nd gear, controlling EM2 to maintain vehicle acceleration through 3rd gear while simultaneously reducing the speed of EM1 and the ICE, aligning the output gear speed of the 4th gear set with the output shaft, and S2 engages 4th gear. At this point, the Sun, Carrier, and Ring of the planetary gear set (EM1, ICE, and EM2) determine the speed ratio through the 3rd and 4th gear sets. EM1, EM2, and the ICE drive the vehicle at proportional speeds and with added torque.

[0060] Therefore, throughout the acceleration process, due to the simultaneous engagement of both clutches with the gear sets and the fixed planetary gears through the two gear sets, the upper limit of torque transmission is increased, and EM1, EM2, and the ICE simultaneously output power, enabling the vehicle to achieve superior acceleration or hill-climbing performance. Different gear combinations can achieve different speed ratios, better matching the operating ranges of EM1, EM2, and the ICE throughout the acceleration process. This example focuses on the differences from other embodiments. In particular, the description of the embodiments described later is relatively simple, and relevant details can be referred to the partial description of the aforementioned embodiments.

[0061] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A hybrid transmission structure for an amphibious vehicle, characterized in that: include: A locker, a first clutch, a second clutch, a third clutch, a first adapter, and a second adapter. The first clutch, the second clutch, and the third clutch are all connected to the first motor. When the first clutch is closed, the first motor is connected to the second gear input gear or the fourth gear input gear through the second adapter. The second clutch is used to control whether the first motor is connected to the jet engine. The third clutch is used to control whether the first motor and the second motor are connected to the engine. The locker is provided on the transmission structure between the first motor and the second motor. The second motor is connected to the engine and is connected to the first gear input gear or the third gear input gear through the first adapter. When in pure electric mode for water travel, the second clutch is in a closed state, and the first clutch, the third clutch, and the lock are all in a disengaged state. The closing of the second clutch allows the first motor to drive the jet engine through the closed second clutch to propel the vehicle on the water. When in hybrid mode for water travel, the detent and second clutch are both in the closed state, and the first and third clutches are both in the open state. The closing of the second clutch allows the first motor to drive the jet engine through the closed second clutch to propel the vehicle on the water. The closing of the detent causes the second motor to rotate forward, pulling the engine to work. The engine cooperates with the second motor to generate electricity as an auxiliary power unit. When in pure electric mode for land travel, the first clutch is in a closed state, and the second clutch, the third clutch, and the lock are all in a disengaged state. The closing of the first clutch enables the first motor to drive the vehicle on land through the closed first clutch and the second clutch. When the hybrid mode is used for land driving, the locker and the first clutch are both in the closed state, and the second clutch and the third clutch are both in the disconnected state; wherein, the closing of the locker causes the second motor to rotate forward to drag the engine to work, and the engine cooperates with the second motor as an auxiliary power unit to generate electricity; when in series hybrid, the closing of the first clutch causes the first motor to drive the vehicle on land through the closed first clutch and the second coupler; when in parallel hybrid, the closing of the first clutch causes the first motor to drive the vehicle on land through the closed first clutch and the second coupler, and the second motor and the engine drive the vehicle on land through the first coupler.

2. The hybrid transmission structure for an amphibious vehicle according to claim 1, characterized in that: The second motor is connected to the engine through a planetary gear set, the outer ring gear of the planetary gear set is connected to the rotor of the second motor, the second motor is connected to the sun gear of the planetary gear set, and the planetary gear carrier of the planetary gear set is connected to the output shaft of the engine; In the hybrid mode for water travel, when the state of charge of the battery is lower than a preset condition, the closing of the lock causes the second motor to rotate forward to pull the engine to work as an auxiliary power unit to supply power to the battery, wherein the planetary gear set acts as a reduction mechanism.

3. The hybrid transmission structure for an amphibious vehicle according to claim 1, characterized in that: In the hybrid mode for traveling on water, the lock is closed so that the second motor rotates forward to start the engine, and then the lock is disconnected to indirectly control the speed of the sun gear by controlling the speed of the second motor and the engine. When the speed of the sun gear is the same as that of the first motor, the third clutch is closed to adjust the engine speed by controlling the speed of the second motor when the speed of the sun gear is constant. At the same time, by controlling the torque of the first motor, the engine torque can be adjusted when the speeds of the sun gear, ring gear and planetary carrier are fixed.

4. The hybrid transmission structure for an amphibious vehicle according to claim 1, characterized in that: When used in the land-water switching mode, the locker and the second clutch are in the closed state, and the first clutch and the third clutch are in the disconnected state; wherein, the closing of the locker enables the second motor to rotate forward to start the engine and then drive the vehicle through the first clutch, and the closing of the second clutch enables the first motor to drive the jet engine through the closed second clutch to propel the vehicle on the water.

5. The hybrid transmission structure for an amphibious vehicle according to claim 1, characterized in that: In a parallel hybrid, when the lock switches from closed to open, the third clutch switches from open to closed, so that the first motor is connected to the sun gear of the planetary gear set through the third clutch, and the second motor drives the ring gear of the planetary gear set, the engine drives the planetary carrier of the planetary gear set, and drives the vehicle through the third clutch.

6. The hybrid transmission structure for an amphibious vehicle according to any one of claims 1 to 5, characterized in that: The first clutch is used for engaging and switching between the first-speed gear set and the third-speed gear set, and the second clutch is used for engaging and switching between the second-speed gear set and the fourth-speed gear set.

7. An amphibious vehicle, characterized in that: It comprises an amphibious vehicle hybrid transmission structure as described in any one of claims 1-6.

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