Dual-motor multi-mode driving system for electric vehicle

Abstract

The application discloses a kind of electric vehicle double motor multi-mode drive system, belongs to pure electric vehicle driving technical field, comprising: first motor, second motor, first synchronizer, second synchronizer, simpson planetary gear set, power output unit and main controller;The output shaft of the first motor is connected with first synchronizer, and the output shaft of the second motor is connected with second synchronizer;First synchronizer and second synchronizer are connected with simpson planetary gear set;Simpson planetary gear set is also connected with the output shaft of first motor, the output shaft of second motor and power output unit respectively;The first motor, second motor, first synchronizer, second synchronizer and power output unit are connected with the main controller.The drive system of the application can reduce the energy consumption of electric vehicle, reduce the volume of drive system, and improve driving efficiency.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of pure electric vehicle driving technology, and more particularly relates to a dual-motor multi-mode driving system for electric vehicles. BACKGROUND

[0002] With the development of automobiles, people have put forward more and more requirements for economy, ride comfort and other performances on the premise of meeting the power performance. Electric vehicles have been greatly developed due to their excellent economic performance. The efficiency of the electric vehicle driving system is a major factor affecting the economy of the electric vehicle. Nowadays, the driving system of commercial electric vehicles mostly adopts a single-motor, fixed-reduction-ratio driving form or a single-motor, multi-gear transmission driving form. The single-motor plus fixed-reduction-ratio driving system cannot meet the economic performance on the premise of meeting the power performance, and cannot fully play the advantages of pure electric vehicles. The single-motor plus multi-gear transmission driving form can improve the economy of the vehicle while ensuring the power performance of the vehicle, but it will inevitably cause power interruption during gear shifting, affecting the driving experience of users.

[0003] In order to improve the economy of electric vehicles and the smoothness during mode switching, more and more dual-motor transmission systems have been proposed. The reason why the dual-motor transmission system improves the economy is that it can drive with a single motor in the case of small power demand, thereby reducing the power loss of the motor. As a kind of solution, the Chinese patent with application number 201910817933.2 discloses a hybrid driving device, whose power system adopts a double planetary gear set structure, including a sun gear, a planet gear, a planet carrier, a ring gear, a brake and a clutch. The power driving device can realize compound power split and output power split, and can realize various pure electric and hybrid driving modes, but its structure is large on a pure electric vehicle, and it is mainly used for hybrid driving. In addition, the conversion of the driving mode needs to rely on the brake and the clutch, both of which need to be powered by a hydraulic system. If it is directly used on a pure electric vehicle, it will increase the energy consumption of the vehicle. SUMMARY

[0004] In view of the defects of the prior art and the improvement needs, the present application provides a dual-motor multi-mode driving system for electric vehicles, which aims to reduce the energy consumption of electric vehicles.

[0005] To achieve the above-mentioned purpose, the present application provides a dual-motor multi-mode driving system for electric vehicles, which comprises a first motor, a second motor, a first synchronizer, a second synchronizer, a Simpson planetary gear set, a power output unit and a main controller.

[0006] The output shaft of the first motor is connected with a first synchronizer, and the output shaft of the second motor is connected with a second synchronizer; the first synchronizer and the second synchronizer are both connected with a Simpson planetary gear set; the Simpson planetary gear set is further connected with the output shaft of the first motor, the output shaft of the second motor and a power output unit respectively; the first motor, the second motor, the first synchronizer, the second synchronizer and the power output unit are all connected with the main controller.

[0007] Further, the Simpson planetary gear set comprises a front planetary gear set ring gear, a front planetary gear set sun gear, a front planetary gear, a front planetary gear carrier, a rear planetary gear set ring gear, a rear planetary gear set sun gear, a rear planetary gear and a rear planetary gear carrier;

[0008] The front planetary gear set ring gear and the front planetary gear set sun gear are both engaged with the front planetary gear, and the front planetary gear is arranged on the front planetary gear carrier;

[0009] The rear planetary gear set ring gear and the rear planetary gear set sun gear are both engaged with the rear planetary gear, and the rear planetary gear is arranged on the rear planetary gear carrier;

[0010] The front planetary gear carrier and the rear planetary gear set ring gear form an integrated component, the front planetary gear set ring gear is connected with the first synchronizer and the output shaft of the first motor respectively; the rear planetary gear carrier is connected with the second synchronizer, and the rear planetary gear set sun gear and the front planetary gear set sun gear are both connected with the output shaft of the second motor.

[0011] Further, the first synchronizer comprises a coaxially arranged first engagement ring gear, a first synchronizing ring, a first engagement sleeve and a first shift fork;

[0012] The first engagement ring gear is connected with the output shaft of the first motor, the first synchronizing ring rotates synchronously with the first engagement ring gear, and the first shift fork is detachably connected with the first engagement sleeve;

[0013] When the first shift fork is separated from the first engagement sleeve, the first engagement sleeve is not engaged with the first synchronizing ring, and when the first shift fork is connected with the first engagement sleeve, the first shift fork pushes the first engagement sleeve to engage with the first synchronizing ring, so that the first synchronizing ring is engaged with the first engagement ring gear, and the first motor connected with the first engagement ring gear is locked.

[0014] Further, the second synchronizer comprises a coaxially arranged second engagement ring gear, a second synchronizing ring, a second engagement sleeve, a second shift fork, a third synchronizing ring and a third engagement ring gear;

[0015] The second engagement ring gear is connected with the rear planetary gear set carrier, the third engagement ring gear is connected with the output shaft of the second motor, the second synchronizing ring rotates synchronously with the second engagement ring gear, the third synchronizing ring rotates synchronously with the third engagement ring gear, and the second shift fork is detachably connected with the second engagement sleeve.

[0016] When the second shift fork is separated from the second engagement sleeve, the second engagement sleeve is not engaged with the second synchronizing ring and the third synchronizing ring; when the second shift fork is connected with the second engagement sleeve, the second shift fork pushes the second engagement sleeve to engage with the second synchronizing ring, so that the second synchronizing ring engages with the second engagement ring gear, and the rear planetary gear set carrier connected with the second engagement ring gear is locked; the second shift fork pushes the second engagement sleeve to engage with the third synchronizing ring, so that the third synchronizing ring engages with the third engagement ring gear, and the second motor connected with the third engagement ring gear is locked.

[0017] Further, the power output unit comprises a main reducer gear set and a differential;

[0018] The main reducer gear set comprises an input gear and an output gear, the input gear and the output gear are engaged, and the output gear is connected with the differential; the front planetary gear set carrier and the rear planetary gear set ring gear integrated member are connected with the input gear.

[0019] Further, the driving system comprises six driving modes, including a first single motor driving mode, a second single motor driving mode, a third single motor driving mode, a fourth single motor driving mode, a double motor torque coupling driving mode, and a double motor speed coupling driving mode.

[0020] The first single motor driving mode is that the first motor is locked, and the second motor drives the electric vehicle through a first fixed transmission ratio i1.

[0021] The second single motor driving mode is that the rear planetary gear set carrier is locked, and the second motor drives the electric vehicle through a second fixed transmission ratio i2.

[0022] The third single motor driving mode is that the second motor is locked, and the first motor drives the electric vehicle through a third fixed transmission ratio i3.

[0023] The fourth single motor driving mode is that the rear planetary gear set carrier is locked, and the first motor drives the electric vehicle through a fourth fixed transmission ratio i4.

[0024] The double motor torque coupling driving mode is that the rear planetary gear set carrier is locked, the first motor drives the electric vehicle through the fourth fixed transmission ratio i4, and the second motor drives the electric vehicle through the second fixed transmission ratio i2.

[0025] The double-motor rotation speed coupling driving mode is that the first motor and the second motor drive the electric vehicle through rotation speed coupling mode with variable transmission ratio.

[0026] The fixed transmission ratio in different driving modes is selected according to the tooth number of the input gear and the output gear of the main reducer gear set and the Simpson planetary gear set.

[0027] Further, the first fixed transmission ratio i1, the second fixed transmission ratio i2, the third fixed transmission ratio i3 and the fourth fixed transmission ratio i4 respectively satisfy:

[0028] i1=i f (1+i p1 )

[0029] i2=i f i p2

[0030] i3=i f (1+i p1 ) / i p1

[0031] i4=i f (1+i p1 +i p2 ) / i p1

[0032] Wherein, i f represents the tooth number ratio of the input gear of the main reducer gear set and the output gear of the main reducer gear set, i p1 represents the tooth number ratio of the ring gear of the front planetary gear set and the sun gear of the front planetary gear set, and i p2 represents the tooth number ratio of the ring gear of the rear planetary gear set and the sun gear of the rear planetary gear set.

[0033] Further, in the double-motor rotation speed coupling driving mode, the first motor, the second motor and the vehicle speed of the electric vehicle satisfy:

[0034]

[0035] Wherein, ω1 and ω2 respectively represent the rotation speed of the first motor and the rotation speed of the second motor, v represents the vehicle speed, and R ω represents the rolling radius of the tire of the electric vehicle.

[0036] Further, the main controller selects the driving mode with the highest efficiency among the six driving modes to drive the electric vehicle according to the principle of efficiency optimization.

[0037] Further, the efficiency η of the driving system satisfies:

[0038]

[0039]

[0040] Wherein, T1, T2 are output torque of the first motor and the second motor in each mode respectively, ω1, ω2 are output speed of the first motor and the second motor in each mode respectively, T c2 , ω c2 Are torque and speed of the rear planetary gear set.

[0041] Overall, the above technical solutions conceived by the present application can achieve the following beneficial effects:

[0042] (1) The present application connects the output shafts of two motors with the first synchronizer and the second synchronizer respectively, and the first synchronizer and the second synchronizer are connected with the Simpson planetary gear set. When the electric vehicle needs to brake, the corresponding synchronizer locks the corresponding motor to achieve braking. In the field of automobiles, the conventional cognition of those skilled in the art is that the synchronizer is mainly used for gear shifting, and the present application innovatively uses the first synchronizer and the second synchronizer as a braking mechanism to replace the traditional brake to achieve braking, avoiding hydraulic power supply, thereby reducing the energy consumption of the whole vehicle.

[0043] (2) Further, the present application also designs the structure of the synchronizer. When the electric vehicle needs to brake, pushing the fork can achieve braking, similar to the dog clutch, the structure is simple, and the braking mode is simple.

[0044] (3) As a preferred embodiment, in the present application, the front planetary gear set and the rear planetary gear set are integrated with the power output unit. Compared with the prior art in which the rear planetary gear set is connected with the power output unit, the connection mode of the present application can compress the horizontal space of the whole system, and the structure will be more compact, reducing the volume of the drive system.

[0045] (4) Based on the connection relationship between the two motors, the Simpson planetary gear set and the power output unit in the present application, the two motors transmit power in different drive modes with different fixed transmission ratios and different power flow transmission routes through different gear positions of the two synchronizers. The main controller selects different drive modes according to the principle of optimal efficiency, so that the motor works at the highest efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0046] Figure 1 The structure diagram of the dual-motor electric vehicle drive system provided by the present application;

[0047] Figure 2 The three-dimensional structure diagram of the first synchronizer provided by the present application;

[0048] Figure 3 A second synchronizer three-dimensional structure schematic diagram provided by the present application;

[0049] Figure 4 A first single motor driving mode power transmission path diagram provided by the present application;

[0050] Figure 5 A second single motor driving mode power transmission path diagram provided by the present application;

[0051] Figure 6 A third single motor driving mode power transmission path diagram provided by the present application;

[0052] Figure 7 A fourth single motor driving mode power transmission path diagram provided by the present application;

[0053] Figure 8 A double motor torque coupling driving mode power transmission path diagram provided by the present application;

[0054] Figure 9 A double motor speed coupling driving mode power transmission path diagram provided by the present application. In all the drawings, the same reference signs are used to represent the same elements or structures, wherein:

[0055] 1 - first motor, 2 - second motor, 3 - first synchronizer, 4 - second synchronizer, 5 - Simpson planetary gear set, 6 - input gear, 7 - output gear, 8 - differential, 31 - first synchronizer fixing seat, 32 - first engagement ring gear, 33 - first synchronizer ring, 34 - first engagement sleeve, 35 - first shift fork, 41 - second synchronizer fixing seat, 42 - second engagement ring gear, 43 - second synchronizer ring, 44 - second engagement sleeve, 45 - second shift fork, 46 - third synchronizer ring, 47 - third engagement ring gear, 51 - front planetary gear set ring gear, 52 - front planetary gear set sun gear, 53 - front planetary gear, 54 - rear planetary gear, 55 - rear planetary gear carrier, 56 - rear planetary gear set sun gear, 57 - front planetary gear carrier and rear planetary gear set ring gear integrated member. DETAILED DESCRIPTION

[0056] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in details below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and should not be used to limit the present application. In addition, the technical features involved in each embodiment of the present application described below can be combined with each other as long as there is no conflict.

[0057] In the present application, the terms "first", "second", and the like in the present application and the drawings are used to distinguish similar objects, and do not necessarily describe a specific order or sequence. The terms "left", "right", "middle", and the like indicate the positional relationship based on the positional relationship shown in the drawings, or the positional relationship when the product of the present application is commonly placed in use, only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation and operation, so it cannot be understood as a limitation on the present application.

[0058] As shown in Figure 1 The electric vehicle dual-motor multi-mode drive system provided by the present application comprises a first motor 1, a second motor 2, a first synchronizer 3, a second synchronizer 4, a Simpson planetary gear set 5, a power output unit, and a main controller. The output shaft of the first motor is connected with the first synchronizer, and the output shaft of the second motor is connected with the second synchronizer. The first synchronizer 3 and the second synchronizer 4 are both connected with the Simpson planetary gear set 5. The Simpson planetary gear set 5 is also connected with the output shaft of the first motor 1, the output shaft of the second motor 2, and the power output unit respectively. The first motor 1, the second motor 2, the first synchronizer 3, the second synchronizer 4, and the power output unit are all connected with the main controller.

[0059] As shown in Figure 2 and Figure 3 The first synchronizer and the second synchronizer are used to brake the first motor or the second motor according to different gears, so that the power transmission path of the motor changes. The first synchronizer 3 acts on the output shaft of the first motor 1, and the second synchronizer 2 acts on the rear planetary carrier 55 of the Simpson planetary gear set 5 when it is locked to the left, and acts on the output shaft of the second motor 2 when it is locked to the right.

[0060] The first synchronizer mainly comprises a coaxially arranged first synchronizer fixing seat 31, a first engagement gear ring 32, a first synchronizing ring 33, a first engagement sleeve 34 and a first shift fork 35, and the first engagement gear ring 32, the first synchronizing ring 33, the first engagement sleeve 34 and the first shift fork 35 are located inside the first synchronizer fixing seat 31 and coaxially arranged with the first synchronizer fixing seat 31; wherein the first synchronizer fixing seat 31 is connected with the gearbox shell and used for fixing the whole synchronizer; the first engagement gear ring 32 is connected with the output shaft of the first motor, the first synchronizing ring 33 rotates synchronously with the first engagement gear ring 32, and the first shift fork 35 is disconnectively connected with the first engagement sleeve 34; when the first shift fork 35 is in the middle position, i.e. the first shift fork 35 is disconnected with the first engagement sleeve 34, the first engagement sleeve 34 is not engaged (not in contact) with the first synchronizing ring 33, and at this time, the first synchronizer is defined as being in the neutral gear, at this time, the first synchronizer does not work, and the first motor is in a free state; when the first shift fork 35 is connected with the first engagement sleeve 34, the first shift fork 35 pushes the first engagement sleeve 34 to move leftwards and engages with the first synchronizer fixing seat 31 and the first synchronizing ring, the first synchronizing ring engages with the first engagement gear ring, and the part connected with the first engagement gear ring is locked, i.e. the first motor is locked, and at this time, the first synchronizer is defined as being in the left gear;

[0061] The second synchronizer mainly comprises a coaxially arranged second synchronizer fixing seat 41, a second engagement gear ring 42, a second synchronizing ring 43, a second engagement sleeve 44, a second shift fork 45, a third synchronizing ring 46 and a third engagement gear ring 47, and the second engagement gear ring 42, the second synchronizing ring 43, the second engagement sleeve 44, the second shift fork 45, the third synchronizing ring 46 and the third engagement gear ring 47 are located inside the second synchronizer fixing seat 41 and coaxially arranged with the second synchronizer fixing seat 41;

[0062] The second synchronizer fixed seat 41 is connected with the gearbox housing, the second engaging ring gear 42 is connected with the rear planetary gear set carrier 55 of the Simpson planetary gear set 5, the third engaging ring gear 47 is connected with the output shaft of the second motor, the second synchronizer ring 43 rotates synchronously with the second engaging ring gear 42, the third synchronizer ring 46 rotates synchronously with the third engaging ring gear 47, and the second shift fork 45 is detachably connected with the second engaging sleeve 44; when the second shift fork 45 is in the middle position, that is, the second shift fork 45 is separated from the second engaging sleeve 44, the second engaging sleeve 44 is not engaged with the second synchronizer ring 43, and the second engaging sleeve 44 is not engaged with the third synchronizer ring 46, and at this time, the second synchronizer is defined as being in the middle gear position, and the second synchronizer is in the non-working state or in the non-locking state; when the second shift fork 45 pushes the second engaging sleeve 44 to move left and is engaged with the second synchronizer fixed seat 41 and the second synchronizer ring 43, the second synchronizer ring 43 is engaged with the second engaging ring gear 42, and the part connected with the second engaging ring gear 42, that is, the rear planetary gear set carrier, is locked, the power transmission path of the motor is changed, and at this time, the second synchronizer is defined as being in the left gear position; the second shift fork 45 pushes the second engaging sleeve 44 to move right and is engaged with the second synchronizer fixed seat 41 and the third synchronizer ring 46, the third synchronizer ring 46 is engaged with the third engaging ring gear 47, and the part connected with the third engaging ring gear 47, that is, the second motor, is locked, and at this time, the second synchronizer is defined as being in the right gear position.

[0063] The power of the first motor and the second motor is output to the power output unit through the Simpson planetary gear set to drive the electric vehicle.

[0064] Specifically, the Simpson planetary gear set includes a front planetary gear set ring gear 51, a front planetary gear set sun gear 52, a front planetary gear 53, a front planetary gear carrier, a rear planetary gear set ring gear, a rear planetary gear set sun gear 56, a rear planetary gear 54, and a rear planetary gear carrier 55; the front planetary gear set ring gear 51 and the front planetary gear set sun gear 52 are engaged with the front planetary gear 53, the front planetary gear carrier is connected with the rear planetary gear set ring gear to form a front planetary gear carrier and rear planetary gear set ring gear integrated component 57, the rear planetary gear set ring gear and the rear planetary gear set sun gear 56 are engaged with the rear planetary gear 54, the front planetary gear is arranged on the front planetary gear carrier, and the rear planetary gear is arranged on the rear planetary gear carrier; the rear planetary gear carrier 55 is connected with the second engaging ring gear 42 of the second synchronizer, and the front planetary gear set ring gear 51 is connected with the first engaging ring gear 32 of the first synchronizer.

[0065] The output shaft of the first motor 1 is connected with the first synchronizer and the front planetary gear row gear ring 51 in sequence; the output shaft of the second motor 2 is connected with the second synchronizer, the rear planetary gear row sun gear 56 and the front planetary gear row sun gear 52 in sequence; the front planetary row carrier and the rear planetary gear row gear ring integrated component are connected with the power output unit;

[0066] The double-motor driving system can have six driving modes, and the conversion of the six driving modes is completed by the first synchronizer and the second synchronizer. The first synchronizer has neutral and left two gears, and the second synchronizer has neutral, left and right three gears. When the first synchronizer is in the neutral gear, the second synchronizer can be in the neutral, left and right gears. When the first synchronizer is in the left gear, the second synchronizer can be in the neutral, left and right gears, forming six driving modes.

[0067] The main controller selects the gear of the first synchronizer or the second synchronizer according to the efficiency optimization principle, so as to select a driving mode with the highest efficiency from the six driving modes to drive the electric vehicle. The six driving modes include the first single-motor driving mode, the second single-motor driving mode, the third single-motor driving mode, the fourth single-motor driving mode, the double-motor torque coupling driving mode and the double-motor speed coupling driving mode.

[0068] The power output unit is used for outputting the power provided by the first motor or / and the second motor to the wheels according to the driving mode selected by the main controller to drive the electric vehicle.

[0069] Specifically, the power output unit includes a main reducer gear set and a differential 8, wherein the main reducer gear set includes an input gear 6 and an output gear 7, the input gear 6 and the output gear 7 are engaged, and the output gear 7 is connected with the differential 8; the front planetary row carrier and the rear planetary gear row gear ring integrated component are connected with the input gear 6 through gears, the input gear 6 and the output gear 7 are engaged and transmitted, and the power is output to the wheels through the differential 8.

[0070] When the first synchronizer is in the neutral position, the first motor drives the front planetary gear set gear ring of the Simpson planetary gear set, the first motor is in the working state (i.e. free state), and the state of the second motor is determined according to the gear state of the second synchronizer; when the first synchronizer is in the left position, the first motor connected with the first engagement gear ring is locked; when the second synchronizer is in the neutral position, the second motor drives the rear planetary gear set sun gear and the front planetary gear set sun gear of the Simpson planetary gear set, and the second motor is in the working state; when the second synchronizer is in the left position, the second motor is in the working state, the second motor drives the rear planetary gear set sun gear and the front planetary gear set sun gear of the Simpson planetary gear set, and the rear planetary gear set carrier connected with the second engagement gear ring 42 is locked; when the second synchronizer is in the right position, the second motor connected with the third engagement gear ring 47 is locked, and the different states correspond to different power transmission paths of the motor.

[0071] The first single-motor driving mode is that the first synchronizer is locked to the left, i.e. the first synchronizer pushes the first engagement sleeve 34 to make the first synchronizer ring 33 engage with the first engagement gear ring 32, the first motor is locked, the second motor drives the electric vehicle through the first fixed transmission ratio, at this time, the second synchronizer is in the neutral position, i.e. the second synchronizer is in the disengaged state with the second engagement sleeve 44, and the power transmission path is as shown in Figure 4 The power of the second motor 2 is sequentially transmitted to the input gear 6 of the main reducer gear set through the rear planetary gear set sun gear 56, the front planetary gear set sun gear 52, the front planetary gear set 53, the front planetary gear set carrier and the rear planetary gear set gear ring integrated component 57.

[0072] The second single-motor driving mode is that the second synchronizer is locked to the left, i.e. the second synchronizer pushes the second engagement sleeve 44 to make the second synchronizer ring 43 engage with the second engagement gear ring 42, the rear planetary gear set carrier is locked, the second motor drives the electric vehicle through the second fixed transmission ratio, at this time, the first synchronizer is in the neutral position, and the power transmission path is as shown in Figure 5 The power of the second motor 2 is sequentially transmitted to the input gear 6 of the main reducer gear set through the rear planetary gear set sun gear 56, the rear planetary gear set 54 and the front planetary gear set carrier and the rear planetary gear set gear ring integrated component 57.

[0073] The third single-motor driving mode is that the second synchronizer is locked to the right, i.e. the second synchronizer pushes the second engagement sleeve 44 to make the third synchronizer ring 46 engage with the third engagement gear ring 47, the second motor is locked, and the first motor drives the electric vehicle through the third fixed transmission ratio; at this time, the first synchronizer is in the neutral position, and the power transmission path is as shown in Figure 6As shown, the power of the first motor 1 is sequentially output to the input gear 6 of the main reducer gear set through the front planetary gear row ring gear 51, the front planetary gear row 53, the front planetary gear row carrier and the rear planetary gear row ring gear integrated component 57.

[0074] The fourth single motor driving mode is that the second synchronizer is locked to the left, i.e. the second shift fork 45 of the second synchronizer pushes the second engagement sleeve 44 to make the second synchronizer ring 43 engage with the second engagement ring gear 42, the rear planetary gear row carrier is locked, and the first motor drives the electric vehicle through the fourth fixed transmission ratio; at this time, the first synchronizer is in the neutral gear; the power transmission path is as shown in Figure 7 As shown, the power of the first motor 1 is sequentially output to the input gear 6 of the main reducer gear set through the front planetary gear row ring gear 51, the front planetary gear row 53, the front planetary gear row carrier and the rear planetary gear row ring gear integrated component 57; the other route is sequentially output to the input gear 6 of the main reducer gear set through the front planetary gear row ring gear 51, the front planetary gear row 53, the front planetary gear row sun gear 52, the rear planetary gear row sun gear 56, the rear planetary gear row 54, the front planetary gear row carrier and the rear planetary gear row ring gear integrated component 57.

[0075] The double motor torque coupling driving mode is that the second synchronizer is locked to the left, the first motor drives the electric vehicle through the fourth fixed transmission ratio, and the second motor drives the electric vehicle through the second fixed transmission ratio; at this time, the first synchronizer is in the neutral gear; the power transmission path is as shown in Figure 8 As shown, the power of the second motor 2 is sequentially output to the input gear 6 of the main reducer gear set through the rear planetary gear row sun gear 56, the rear planetary gear row 54 and the front planetary gear row carrier and the rear planetary gear row ring gear integrated component 57; the power of the first motor 1 is sequentially output to the input gear 6 of the main reducer gear set through the front planetary gear row ring gear 51, the front planetary gear row 53, the front planetary gear row carrier and the rear planetary gear row ring gear integrated component 57, and the other route is sequentially output to the input gear 6 of the main reducer gear set through the front planetary gear row ring gear 51, the front planetary gear row 53, the front planetary gear row sun gear 52, the rear planetary gear row sun gear 56, the rear planetary gear row 54, the front planetary gear row carrier and the rear planetary gear row ring gear integrated component 57.

[0076] The double motor speed coupling driving mode is that the first and second synchronizers are not locked (i.e. the first and second synchronizers are in the neutral gear), the first motor and the second motor drive the electric vehicle through the speed coupling mode with variable transmission ratio. The power transmission path is as shown in Figure 9As shown, the power of the first motor 1 is sequentially output to the input gear 6 of the main reducer gear set through the front planetary gear row gear ring 51, the front planetary gear row 53, the front planetary row carrier and the rear planetary gear row gear ring integrated component 57; the power of the second motor 2 is sequentially output to the input gear 6 of the main reducer gear set through the rear planetary gear row sun gear 56, the front planetary gear row sun gear 52, the front planetary gear row 53 and the front planetary row carrier and the rear planetary gear row gear ring integrated component 57.

[0077] According to the tooth number of the input gear and the output gear of the main reducer gear set of the power output unit and the Simpson planetary gear row, different fixed transmission ratios are selected.

[0078] Specifically, the specific formula for calculating the first fixed transmission ratio is:

[0079] i1=i f (1+i p1 )

[0080] Wherein, i1 represents the first fixed transmission ratio, i f represents the tooth number ratio of the input gear of the main reducer gear set and the output gear of the main reducer gear set, i p1 represents the tooth number ratio of the front planetary gear row gear ring and the front planetary gear row sun gear.

[0081] The specific formula for calculating the second fixed transmission ratio is:

[0082] i2=i f i p2

[0083] Wherein, i2 represents the second fixed transmission ratio, i f represents the tooth number ratio of the input gear of the main reducer gear set and the output gear of the main reducer gear set, i p2 represents the tooth number ratio of the rear planetary gear row gear ring and the rear planetary gear row sun gear.

[0084] The specific formula for calculating the third fixed transmission ratio is:

[0085] i3=i f (1+i p1 ) / i p1

[0086] Wherein, i3 represents the third fixed transmission ratio, i f represents the tooth number ratio of the input gear of the main reducer gear set and the output gear of the main reducer gear set, i p1 represents the tooth number ratio of the front planetary gear row gear ring and the front planetary gear row sun gear.

[0087] The specific formula for calculating the fourth fixed transmission ratio is:

[0088] i4 = i f (1 + i p1 ) / i p2 ) / i p1

[0089] wherein i4 represents the fourth fixed transmission ratio, i f represents the gear ratio of the input gear of the main reducer gear set and the output gear of the main reducer gear set, i p1 represents the gear ratio of the ring gear of the front planetary gear set and the sun gear of the front planetary gear set, i p2 represents the gear ratio of the ring gear of the rear planetary gear set and the sun gear of the rear planetary gear set.

[0090] In the rotational speed driving mode, the relationship between the first motor, the second motor and the vehicle speed of the electric vehicle is:

[0091]

[0092] wherein ω1 represents the rotational speed of the first motor, ω2 represents the rotational speed of the second motor, v represents the vehicle speed, R ω represents the rolling radius of the tire of the electric vehicle, i f represents the gear ratio of the input gear of the main reducer gear set and the output gear of the main reducer gear set, i p1 represents the gear ratio of the ring gear of the front planetary gear set and the sun gear of the front planetary gear set, i p2 represents the gear ratio of the ring gear of the rear planetary gear set and the sun gear of the rear planetary gear set.

[0093] The main controller determines the state of the brake and the motor according to the mode switching control strategy in the energy management strategy, i.e. the principle of optimal comprehensive efficiency of the power system, so as to realize the selection of the above six modes, select one driving mode from the six driving modes to drive the electric vehicle, and further improve the efficiency of the transmission system.

[0094] wherein the driving efficiency corresponding to different driving modes is related to the output torque and rotational speed of the first motor and the second motor, the torque and rotational speed of the carrier of the rear planetary gear set, and the gear ratio i p1 of the ring gear of the front planetary gear set and the sun gear of the front planetary gear set, the gear ratio i p2 of the ring gear of the rear planetary gear set and the sun gear of the rear planetary gear set, i p1 , i p2And related to the fixed transmission ratio under different driving modes; that is, the efficiency of the double-motor driving system designed by the application is related to the fixed transmission ratio under different driving modes, based on the special connection relationship between the two motors, the simpson planetary gear set and the power output unit of the application, the motor transmits power in different power flow transmission routes under different fixed transmission ratios through different gear states of the two synchronizers, and the main controller selects different driving modes according to the efficiency optimization principle, so that the motor works at the highest efficiency.

[0095] Specifically, the relationship between the efficiency η of the driving system and the output torque and output speed of the first motor and the second motor, the torque and speed of the rear planetary gear set is:

[0096]

[0097] Wherein, T1 and T2 are the output torque of the first motor and the second motor under each mode, ω1 and ω2 are the output speed of the first motor and the second motor under each mode, T c2 is the torque of the rear planetary gear set, ω c2 is the speed of the rear planetary gear set, v is the current vehicle speed, R ω is the tire radius;

[0098]

[0099] Wherein, T1, T2, ω1, ω2, T c2 are all related to i p1 , i p2 , that is, T1=T1(i p1 , i p2 ), T2=T2(i p1 , i p2 ), ω1=ω1(i p1 , i p2 ), ω2=ω2(i p1 , i p2 ), T c2 =T c2 (i p1 , i p2 ); i f represents the tooth number ratio of the input gear and the output gear of the main reducer gear set, i p1 represents the tooth number ratio of the front planetary gear set gear and the front planetary gear set sun gear, and i p2 represents the tooth number ratio of the rear planetary gear set gear and the rear planetary gear set sun gear.

[0100] The application has torque coupling driving mode and speed coupling driving mode, the vehicle can adapt to more working conditions, and power performance is improved; during mode switching, at least one motor is in working state, so that mode switching impact is reduced, and smoothness is improved.

[0101] The double-motor multi-mode driving system of the application considers vehicle power performance and economy, only one motor is used for driving when the vehicle needs small power, and two motors are used for driving when the vehicle needs large power, so that the economy of the vehicle is improved; and in the single-motor driving mode, the two motors have different transmission ratios and are suitable for different driving conditions, such as city, off-road, high-speed and different working conditions, so that the economy of low power is optimized; in the double-motor driving mode, the two motors have speed coupling and torque coupling to optimize the economy in high-power working conditions; and the driving system has two motors, at least one motor is in working state, so that there is no power interruption problem.

[0102] More importantly, the first synchronizer and the second synchronizer are used as brake mechanisms to replace the traditional brake to realize braking, different driving modes are realized through the synchronizer, a hydraulic system is not needed to maintain the state of each driving mode, and additional energy consumption exchange required for realizing different driving modes by using the clutch or brake depending on the hydraulic system can be effectively avoided.

[0103] When the electric vehicle needs to brake, the push fork can realize braking, similar to the dog clutch, the structure is simple, and the braking mode is simple; and the synchronizer gear shifting can ensure that the gear is not impacted during gear shifting, the operation is easy, and the gear shifting time is shortened.

[0104] By connecting the front planetary row planetary carrier and the rear planetary gear row gear ring integrated component with the power output unit, compared with the connection of the rear planetary row planetary carrier and the power output unit in the prior art, the connection mode of the output power of the application can compress the horizontal space of the whole system, the structure will be more compact, and the volume of the driving system is reduced.

[0105] Those skilled in the art can easily understand that the above description is only a preferred embodiment of the application, and is not used to limit the application, and any modification, equivalent replacement and improvement made within the spirit and principle of the application shall be included in the protection scope of the application.

Claims

1. An electric vehicle dual-motor multi-mode drive system, characterized by, The application relates to a power output unit of an electric vehicle, which comprises a first motor (1), a second motor (2), a first synchronizer (3), a second synchronizer (4), a Simpson planetary gear train (5), a power output unit and a main controller. The output shaft of the first motor (1) is connected with the first synchronizer (3), the output shaft of the second motor (2) is connected with the second synchronizer (4), the first synchronizer (3) and the second synchronizer (4) are connected with the Simpson planetary gear train (5), the Simpson planetary gear train (5) is further connected with the output shaft of the first motor (1), the output shaft of the second motor (2) and the power output unit, and the first motor (1), the second motor (2), the first synchronizer (3), the second synchronizer (4) and the power output unit are all connected with the main controller. The first synchronizer comprises coaxially arranged first engagement ring gear (32), first synchronizing ring (33), first engagement sleeve (34) and first shift fork (35). The first engagement ring gear (32) is connected with the output shaft of the first motor, the first synchronizing ring (33) rotates synchronously with the first engagement ring gear (32), and the first shift fork (35) is disconnectably connected with the first engagement sleeve (34). When the first shift fork is disconnected from the first engagement sleeve, the first engagement sleeve is not engaged with the first synchronizing ring; when the first shift fork is connected with the first engagement sleeve, the first shift fork pushes the first engagement sleeve to engage with the first synchronizing ring, so that the first synchronizing ring is engaged with the first engagement ring gear, and the first motor connected with the first engagement ring gear is locked. The second synchronizer (4) comprises coaxially arranged second engagement ring gear (42), second synchronizing ring (43), second engagement sleeve (44), second shift fork (45), third synchronizing ring (46) and third engagement ring gear (47). The second engagement ring gear (42) is connected with the planet carrier (55) of the rear planetary gear train, the third engagement ring gear (47) is connected with the output shaft of the second motor, the second synchronizing ring (43) rotates synchronously with the second engagement ring gear (42), the third synchronizing ring (46) rotates synchronously with the third engagement ring gear (47), and the second shift fork (45) is disconnectably connected with the second engagement sleeve (44). When the second shift fork is disconnected from the second engagement sleeve, the second engagement sleeve is not engaged with the second synchronizing ring and the third synchronizing ring; when the second shift fork is connected with the second engagement sleeve, the second shift fork pushes the second engagement sleeve to engage with the second synchronizing ring, so that the second synchronizing ring is engaged with the second engagement ring gear, the planet carrier of the rear planetary gear train connected with the second engagement ring gear is locked, the second shift fork pushes the second engagement sleeve to engage with the third synchronizing ring, so that the third synchronizing ring is engaged with the third engagement ring gear, and the second motor connected with the third engagement ring gear is locked. The power output unit is used for outputting the power provided by the first motor or / and the second motor to wheels to drive the electric vehicle according to the driving mode selected by the main controller. The power output unit comprises a main reducer gear set and a differential (8). ​ The main reducer gear set comprises an input gear (6) and an output gear (7), the input gear (6) and the output gear (7) are engaged, and the output gear (7) is connected with a differential (8); the front planetary gear set carrier and the rear planetary gear set ring are integrated components connected with the input gear (6).

2. The drive system of claim 1, wherein, The Simpson planetary gear set (5) comprises a front planetary gear set ring (51), a front planetary gear set sun gear (52), a front planetary gear (53), a front planetary gear set carrier, a rear planetary gear set ring, a rear planetary gear set sun gear (56), a rear planetary gear (54) and a rear planetary gear set carrier (55); The front planetary gear set ring (51) and the front planetary gear set sun gear (52) are engaged with the front planetary gear (53), and the front planetary gear (53) is arranged on the front planetary gear set carrier; The rear planetary gear set ring and the rear planetary gear set sun gear (56) are engaged with the rear planetary gear (54), and the rear planetary gear (54) is arranged on the rear planetary gear set carrier (55); The front planetary gear set carrier and the rear planetary gear set ring are integrated components, the front planetary gear set ring (51) is connected with the output shaft of the first synchronous motor and the first motor respectively; the rear planetary gear set carrier (55) is connected with the second synchronous motor, and the rear planetary gear set sun gear (56) and the front planetary gear set sun gear (52) are connected with the output shaft of the second motor.

3. The drive system of claim 1, wherein, The driving system comprises six driving modes, including a first single motor driving mode, a second single motor driving mode, a third single motor driving mode, a fourth single motor driving mode, a double motor torque coupling driving mode and a double motor speed coupling driving mode; The first single-motor driving mode is that the first motor is locked and the second motor is driven through a first fixed transmission ratio Driving an electric vehicle; The second single-motor driving mode is that the rear planetary gear set carrier is locked, and the second motor drives the vehicle through a second fixed transmission ratio Driving an electric vehicle; The third single-motor driving mode is that the second motor is locked, and the first motor drives the vehicle through a third fixed transmission ratio Driving an electric vehicle; The fourth single-motor driving mode is that the rear planetary carrier is locked, and the first motor drives the vehicle through the fourth fixed transmission ratio Driving an electric vehicle; The double-motor torque coupling driving mode is that the rear planetary gear set carrier is locked, the first motor drives the electric vehicle through the fourth fixed transmission ratio The second motor drives the electric vehicle through the second fixed transmission ratio The second motor drives the electric vehicle through the second fixed transmission ratio The double motor speed coupling driving mode is that the first motor and the second motor drive the electric vehicle through speed coupling in a variable transmission ratio; Wherein, according to the input gear and the output gear of the main reducer gear set and the Simpson planetary gear set, the fixed transmission ratio in different driving modes is selected.

4. The drive system of claim 3, wherein, the first fixed transmission ratio , the second fixed transmission ratio , the third fixed transmission ratio and the fourth fixed transmission ratio respectively wherein represents the gear ratio of the input gear of the main reduction gear set to the output gear of the main reduction gear set, represents the gear ratio of the ring gear of the front planetary gear set to the sun gear of the front planetary gear set, represents the gear ratio of the ring gear of the rear planetary gear set to the sun gear of the rear planetary gear set.

5. The drive system of claim 4, wherein, In the double motor speed coupling driving mode, the first motor, the second motor and the vehicle speed of the electric vehicle satisfy: wherein, , respectively represent a rotational speed of the first motor, a rotational speed of the second motor, represents a vehicle speed, represents a rolling radius of the electric vehicle tire.

6. The drive system according to any one of claims 3 to 5, wherein The main controller selects the driving mode with the highest efficiency in the six driving modes to drive the electric vehicle according to the principle of optimal efficiency.

7. The drive system of claim 6, wherein, Efficiency of the drive system satisfies: wherein, Tout1 and Tout2 are the output torques of the first and second electric motors, respectively, Nout1 and Nout2 are the output speeds of the first and second electric motors, respectively, , Tout3 and Nout3 are the torque and speed of the rear planetary set carrier, respectively.

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