Transmission mechanism for electric vehicle, range extending device, range extending system and electric vehicle

Abstract

The utility model provides a transmission mechanism, a range extending device and a range extending system for an electric vehicle and the electric vehicle. The transmission mechanism comprises a first input shaft (10) and a second input shaft (12); a first clutch (2) and a second rotating member (22); a reduction gear (3) comprising a first input gear (32) and a ring gear (33) having inner teeth and outer teeth, the first input gear being connected to the second input shaft and meshing with the inner teeth and the ring gear being connected to the first clutch; a differential (7); an intermediate shaft; first and second intermediate gears disposed on the intermediate shaft; one end part of each output shaft is in power connection with the differential mechanism; and a second clutch (6) provided between the first intermediate gear and the other end of each output shaft opposite to the one end on the power transmission path of the transmission mechanism.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of new energy vehicles, in particular to a transmission mechanism for an electric vehicle, a range extending device for an electric vehicle, a range extending system for an electric vehicle and an electric vehicle. BACKGROUND

[0002] With the lack of oil resources and the improvement of people's environmental awareness, it is urgent to develop green and environmentally friendly vehicle products that can save energy and have low or even zero emissions. For this reason, new energy vehicles such as electric vehicles are increasingly concerned. Compared with the internal combustion engine of a conventional vehicle, the traction motor of an electric vehicle has a wider operating range, and the constant torque at low speed and constant power at high speed of the motor are more suitable for the operating requirements of the vehicle. In recent years, the power drive system and its operating mode for electric vehicles have become a research hotspot.

[0003] The prior art discloses a range extending system or power coupling system for an electric vehicle, which includes an internal combustion engine, a generator and a drive motor. In this technology, both the generator and the drive motor are used at the same time, resulting in a complex vehicle structure, a large space occupation and an increased manufacturing cost. In addition, the internal combustion engine and the generator are directly connected in power in this prior art, and the internal combustion engine and the generator cannot be flexibly controlled. The output of the drive motor needs to be decelerated, and the prior art usually uses a common planetary gear set to decelerate the motor output, resulting in a heavy system and a reduced transmission efficiency.

[0004] Therefore, there is a need for an improved electric vehicle, in particular an improved range extending system for an electric vehicle. CONTENT OF THE INVENTION

[0005] The purpose of the present application is to provide a transmission mechanism, a range extending device and a range extending system for an electric vehicle, which are simple in structure and save space, and an electric vehicle.

[0006] To solve the above technical problem, the present disclosure provides a transmission mechanism for an electric vehicle, characterized by comprising: a first input shaft; a second input shaft; a first clutch provided between the first input shaft and the second input shaft, the first clutch having a first rotating member and a second rotating member capable of being engaged and disengaged from each other, the first rotating member of the first clutch being connected to the first input shaft; a reduction device provided between the first clutch and the second input shaft, the reduction device including a first input gear and a ring gear, the ring gear having inner teeth on a radially inner surface of the ring gear and outer teeth on a radially outer surface of the ring gear, the first input gear being connected to the second input shaft on one side and engaged with the inner teeth on the other side, and the ring gear being connected to the second rotating member of the first clutch, whereby power from the first input shaft and power from the second input shaft can be coupled at the ring gear; a differential provided with a second input gear on a differential housing; an intermediate shaft; a first intermediate gear and a second intermediate gear arranged on the intermediate shaft, the first intermediate gear being engaged with the outer teeth of the ring gear, and the second intermediate gear being power-connectable to the first intermediate gear on one side and power-connectable to the second input gear of the differential on the other side, whereby the second input gear can be power-connected to the ring gear; two output shafts, one end of each of the two output shafts being power-connected to the differential, whereby power from the differential can be transmitted; and a second clutch provided between the first intermediate gear and the other end of each of the two output shafts opposite to the one end in a power transmission path of the transmission mechanism, whereby power transmission between the first intermediate gear and the other end of each of the output shafts can be allowed or disconnected.

[0007] The transmission mechanism for an electric vehicle according to the present disclosure is compact in structure, improves the utilization rate of in-vehicle space, reduces the motor output with a simple configuration, and can quickly disconnect the power transmission of the driving device to the wheels.

[0008] Preferably, in the radial direction of the ring gear, the engagement point of the first input gear with the inner teeth of the ring gear and the engagement point of the first intermediate gear with the outer teeth of the ring gear overlap.

[0009] According to one aspect of the present disclosure, the first input gear is engaged with the inner teeth of the ring gear on the side of the ring gear close to the first intermediate gear.

[0010] According to another aspect of the present disclosure, the first input gear meshes with the inner teeth of the ring gear on a side of the ring gear distal from the first intermediate gear, and the speed reduction device further includes a first stationary point transition gear and a second stationary point transition gear, the first transition gear is disposed between and meshes with the first input gear and the second transition gear, respectively, and the second transition gear meshes with the inner teeth of the ring gear.

[0011] Preferably, the first and second transition gears are supported by a common gear carrier. Also, preferably, the gear centers of the first input gear, the ring gear, the first transition gear, the second transition gear, and the first intermediate gear are arranged on a straight line.

[0012] The second clutch can be a dog clutch. The first clutch can be a friction clutch.

[0013] According to the transmission mechanism structure for an electric vehicle of the present disclosure, the force acting on the ring gear can be effectively counteracted by overlapping the meshing point of the first input gear with the inner teeth of the ring gear and the meshing point of the first intermediate gear with the outer teeth of the ring gear in the radial direction of the ring gear.

[0014] Preferably, the second clutch is a dog clutch, and the first clutch is a friction clutch.

[0015] According to an aspect of the present disclosure, the second clutch is disposed between the first intermediate gear and the second intermediate gear, thereby allowing or interrupting the transmission of power between the first intermediate gear and the second intermediate gear.

[0016] According to an aspect of the present disclosure, the second clutch is disposed on either one of the two output shafts, thereby interrupting the transmission of power between the differential and the other end portion.

[0017] The transmission mechanism for an electric vehicle further includes a damper disposed between the first input shaft and the first clutch, an input end of the damper being power connected to the first input shaft, and an output end of the damper being power connected to a first rotating member of the first clutch.

[0018] The damper is a torsional damper.

[0019] The present disclosure provides a range extender for an electric vehicle, characterized by comprising: an electric motor generator; and the aforementioned transmission mechanism for an electric vehicle, wherein a second input shaft of the transmission mechanism for an electric vehicle is power connected to the electric motor generator.

[0020] The motor generator is a permanent magnet synchronous motor.

[0021] The present disclosure provides a range extending system for an electric vehicle, characterized by comprising: an internal combustion engine; the aforementioned range extending device for an electric vehicle, wherein a first input shaft of the transmission mechanism for an electric vehicle is in power connection with the internal combustion engine.

[0022] The internal combustion engine is an in-line 4-cylinder internal combustion engine.

[0023] The present disclosure provides an electric vehicle, characterized by comprising: the range extending system for an electric vehicle; a power battery, in which the electric power generated by the range extending system is stored; and a pair of wheels, which are a pair of front wheels or a pair of rear wheels of the electric vehicle, wherein the other end of each of the two output shafts of the transmission mechanism for an electric vehicle is in power connection with a corresponding one of the pair of wheels.

[0024] The electric vehicle comprises a main drive, which comprises a main drive motor and a main speed reducer in power connection with the main drive motor, and the main drive is powered by a power battery of the electric vehicle, wherein the main drive is used to drive a pair of wheels different from the pair of wheels driven by the range extending system for an electric vehicle.

[0025] When the range extending device for an electric vehicle is used to drive a pair of front wheels of an electric vehicle, the main drive is used to drive a pair of rear wheels of the electric vehicle. During vehicle travel, the main drive is always in operation, and the range extending device for an electric vehicle is operated in time according to the vehicle's own conditions and road conditions, etc. for driving, for generating electricity, or for both driving and generating electricity.

[0026] The present disclosure also provides a method for controlling the range extending device for an electric vehicle, characterized by comprising: step S21: judging the size relationship between the state of charge (SOC) of the power battery of the electric vehicle and the SOC threshold value, or simultaneously judging the size relationship between the SOC of the power battery of the electric vehicle and the SOC threshold value and the size relationship between the vehicle speed of the electric vehicle and the vehicle speed threshold value; and step S22: selecting the working mode of the range extending device according to the judgment result.

[0027] The present disclosure also provides a computer readable medium, which comprises a program containing a plurality of instructions, wherein when the program runs on a vehicle-mounted computer, the instructions execute the method for controlling the range extending system for an electric vehicle. The computer readable medium is, for example, a program carrier, such as a hard disk, etc.

[0028] The reducer, the range extending device and the range extending system for the electric vehicle according to the present disclosure are compact in structure, improve the utilization rate of the in-vehicle space, reduce the motor output in a simple configuration, and can rapidly disconnect the power transmission from the driving device to the wheels. By using the method for controlling the range extending device for the electric vehicle according to the present disclosure, the switching of multiple working modes can be automatically realized according to the SOC of the power battery and the vehicle speed. BRIEF DESCRIPTION OF DRAWINGS

[0029] The features, advantages, and technical and industrial significance of the exemplary embodiments of the present application will be described below with reference to the accompanying drawings, wherein the same reference numerals denote the same elements throughout the drawings. It should be noted that the drawings described below are only some embodiments of the present application, and those skilled in the art can make changes to the drawings without creative labor.

[0030] Figure 1 is a structural schematic diagram of a transmission mechanism, a range extending device and a range extending system for an electric vehicle according to a first embodiment.

[0031] Figure 2 is a schematic diagram of the state when the first input gear, the ring gear and the first intermediate gear of the transmission mechanism according to the first embodiment are engaged.

[0032] Figure 3 is a structural schematic diagram of a transmission mechanism, a range extending device and a range extending system for an electric vehicle according to a second embodiment.

[0033] Figure 4 is a structural schematic diagram of a transmission mechanism, a range extending device and a range extending system for an electric vehicle according to a third embodiment.

[0034] Figure 5 is a schematic diagram of the state when the first input gear, the ring gear, the first transition gear and the second transition gear of the transmission mechanism according to the third embodiment are engaged.

[0035] Figure 6 is a structural schematic diagram of a transmission mechanism, a range extending device and a range extending system for an electric vehicle according to a fourth embodiment.

[0036] Figure 7 is a comparison diagram of the SOC and the vehicle speed with respective threshold values. DETAILED DESCRIPTION

[0037] The various embodiments of the present application are described below with reference to the accompanying drawings, which are used to illustrate specific embodiments of the present application that can be implemented. The expressions "left" and "right" and the like (if any) appearing in the specification are merely used to refer to the accompanying drawings to describe the present application and are not intended to limit the present application, and it is understood that the expressions "left" or "right" merely indicate a direction and are reversible. Certain terms used in the specification are used for convenience only and are not limiting. The words "axial", "radial", "circumferential", "outward", "inward", "up" and "down" and the like (if any) indicate directions in the referenced drawings. Unless otherwise expressly stated, each numerical value and range, as well as shape (if any), should be interpreted as approximate, as if the term "about", "approximately" or "substantially" preceded the value or range. The terms "about", "substantially" and the like are intended to mean considerably large or most of the specified range but not necessarily exactly (but can include exactly) the specified range.

[0038] <system configuration>

[0039] First embodiment:

[0040] Figure 1 is a structural diagram of a transmission mechanism, a range extender and a range extending system for an electric vehicle according to the first embodiment. As shown in Figure 1 The range extending system for an electric vehicle according to the first embodiment includes an internal combustion engine 1, an electric motor generator 4, and a transmission mechanism located between the internal combustion engine 1 and the electric motor generator 4, as shown by the dashed line box. The transmission mechanism is capable of coupling and outputting power from the internal combustion engine 1 and the electric motor generator 4. The internal combustion engine 1 and the electric motor generator 4 are preferably located on opposite sides of the transmission mechanism.

[0041] The transmission mechanism includes two input shafts, a first input shaft 10 and a second input shaft 12. The first input shaft 10 and the second input shaft 12 are both rotatably supported. The first input shaft 10 and the second input shaft 12 are used to receive power input from respective power sources, such as the internal combustion engine 1 and the electric motor generator 4.

[0042] The transmission further comprises a first clutch 2 arranged between the first input shaft 10 and the second input shaft 12. The first clutch 2 comprises a first rotary part 21 and a second rotary part 22 which can be engaged and disengaged from each other. The first rotary part 21 is connected to the first input shaft 10 to receive power therefrom and thereby to the internal combustion engine 1, in particular to the crankshaft of the internal combustion engine. The connection between the first rotary part 21 and the first input shaft 10 can be a direct connection such as a form fit connection or a friction fit connection, or an indirect connection such as a connection through a conventional coupling. The second rotary part 22 is power connected to the second input shaft 12 (e.g. via the reduction gear 3, as described below) and thereby to the motor generator 4, in particular to the output shaft of the motor generator. Thereby, the first clutch 2 can power connect the first input shaft 10 with the second input shaft 12. Accordingly, the first clutch 2 can power connect the internal combustion engine 1 with the motor generator 4. In the present disclosure, the term "power connected" is a connection in which two parts are connected directly or indirectly in a manner that power can be transmitted.

[0043] The transmission for an electric vehicle further comprises a reduction gear 3. The reduction gear 3 is arranged between the first clutch 2 and the second input shaft 12 which can be connected to the motor generator 4. The reduction gear 3 comprises a first input gear 32 and a ring gear 33. The first input gear 32 is located radially inside the ring gear 33. The ring gear 33 has inner teeth 331 on a radially inner surface of the ring gear and outer teeth 332 on a radially outer surface of the ring gear. The first input gear 32 is connected to the second input shaft 12 on one hand and is in mesh with the inner teeth 331 on the other hand, and the ring gear 33 is connected to the second rotary part 22 of the first clutch 2. Thereby, power from the first input shaft 10 and power from the second input shaft 12 can be coupled together at the ring gear 33.

[0044] The transmission for an electric vehicle further comprises a differential 7 which is provided with a second input gear 70 on a differential housing which can be power connected with the reduction gear 3, thereby receiving power from the reduction gear 3.

[0045] The transmission for an electric vehicle further comprises an intermediate shaft 222, a first intermediate gear 24 and a second intermediate gear 25. The first intermediate gear 24 and the second intermediate gear 25 are located on the intermediate shaft 222, and at least one of the intermediate gears is non-rotatably connected to the intermediate shaft 222. The axis of the intermediate shaft 222 is different from the rotational axis of the ring gear 33 of the reduction gear 3 and the rotational axis of the output shaft 71 of the differential 7, and is located therebetween. The first intermediate gear 24 is in mesh with the external teeth 332 of the ring gear 33. The second intermediate gear 25 is on the one hand power-connectable with the first intermediate gear 24 to receive power from the first intermediate gear 24, and on the other hand power-connectable with the second input gear 70 of the differential, preferably in mesh with the second input gear 70. Thereby, the second input gear 70 is power-connectable with the ring gear 33, in particular the external teeth 332 of the ring gear 33. In particular, the intermediate shaft 222 can be rotatably supported, one of the first intermediate gear 24 and the second intermediate gear 25 is non-rotatably arranged on or integrated with the intermediate shaft 222, and the other intermediate gear is rotatably arranged on the intermediate shaft 222, or both the first intermediate gear 24 and the second intermediate gear 25 are non-rotatably arranged on or integrated with the intermediate shaft 222, as desired. The term "non-rotatably connected" is a connection in which two components are rigidly connected together without being able to rotate relative to each other.

[0046] The transmission for an electric vehicle further comprises two output shafts 71. One end of each of the two output shafts 71 is power-connectable with the differential 7, thereby being able to transmit power from the differential 7. For example, the output shafts 71 are used to transmit power to a pair of wheels of the electric vehicle. In particular, the other end of each output shaft 71 opposite the one end power-connectable to the differential 7 can be connected to a respective one of a pair of wheels 8 of the electric vehicle for transmitting power from the differential 7 to the pair of wheels 8. The pair of wheels 8 is a pair of front wheels or a pair of rear wheels of the electric vehicle.

[0047] The transmission for an electric vehicle further comprises a second clutch 6 provided in the power transmission path of the transmission between the first intermediate gear 24 and the other end of each of the two output shafts 71 opposite the one end, thereby being able to allow or interrupt power transmission between the first intermediate gear 24 and the other end of each output shaft.

[0048] In particular, as shown in Figure 1 the second clutch 6 is located on the intermediate shaft 222 and provided between the first intermediate gear 24 and the second intermediate gear 25, thereby being able to allow or interrupt power transmission between the first intermediate gear 24 and the second intermediate gear 25.

[0049] Figure 2 This is a schematic diagram showing the state of engagement of the first input gear, the gear ring, and the first intermediate gear in the transmission mechanism according to the first embodiment. Figure 2 Combination Figure 1 As shown, in the radial direction of the gear ring 33, the meshing point of the first input gear 32 with the gear ring 33 (specifically the internal teeth 331) and the meshing point of the first intermediate gear 24 with the gear ring 33 (specifically the external teeth 332) approximately overlap. That is, these two meshing points are arranged approximately in a straight line in the radial direction of the gear ring 33, as shown... Figure 2 As shown by the dashed line. In other words, these two meshing points are located at approximately the same position or the same circumferential angle on the circumference of the gear ring.

[0050] Furthermore, such as Figure 2 As shown, the first input gear 32 meshes with the internal teeth 331 of the gear ring 33 on the side of the gear ring 33 closest to the first intermediate gear 24. Thus, during the transmission of power from the first input gear 32 through the gear ring 33 to the first intermediate gear 24, by arranging these two meshing points to overlap each other in the radial direction of the gear ring 33, the forces on the gear ring, particularly the radial and axial forces, are counteracted. Accordingly, the reduction device according to this disclosure can reduce the rotational output of the drive source with a simple construction and in a stable manner. This further reduces costs.

[0051] The type of the second clutch 6 is not limited. However, preferably, the second clutch 6 is a dog clutch (also known as a canine clutch or claw clutch). The dog clutch can be a radial tooth dog clutch or an axial tooth dog clutch. The dog clutch includes a first external spline (not shown) disposed on the first intermediate gear 24, a second external spline (not shown) disposed on the second intermediate gear 25, and a sliding sleeve (not shown) provided with an internal spline. The sliding sleeve is slidably disposed on one of the external splines of the first and second external splines via its internal spline, and is axially actuated when engagement is required to make its internal spline mesh with the other external spline, thereby realizing the synchronous rotation of the first and second intermediate gears. The structural features of the dog clutch are simple structure, low drag loss, small size, and no relative rotation of the two shafts after engagement; convenient operation, ability to transmit large torque, effective prevention of overload and overheating, and extension of equipment service life; and fast response characteristics. Using this jaw clutch, the transmission mechanism for electric vehicles according to this disclosure is smaller in size and can quickly drive the electric vehicle (main drive or auxiliary drive). In the case where an intermediate gear is arranged anti-rotationally on or integral with the intermediate shaft 222, an external spline of the jaw clutch corresponding to the intermediate gear can be directly formed on the intermediate shaft 222.

[0052] The first clutch 2 can be any type of clutch, such as a friction clutch. A friction clutch has the advantage of being simple in construction and relatively low in cost. As mentioned above, the second rotary part 22 of the first clutch 2 is power connected to the ring gear 33 of the reduction gear 3. It is readily understood that the second rotary part 22 of the first clutch 2 can be fixed to or integrated with the ring gear 33 of the reduction gear 3.

[0053] The differential 7 is of a conventional type. As mentioned above, each output shaft 71 of the transmission mechanism is power connected to the differential 7 at the one end of the output shaft 71 and to the respective one wheel 8 of the electric vehicle at the other end of the output shaft 71. In this case, the output shaft 71 of the transmission mechanism can also be regarded as an output shaft of the differential 7 itself. The specific construction of the differential can be known and will not be described in detail herein.

[0054] The first rotary part 21 of the first clutch 2 can be directly power connected to a power source, such as the internal combustion engine 1. Preferably, for the purpose of buffering or damping the output of the external power source, such as the internal combustion engine 1, the transmission mechanism for the electric vehicle can be provided with a damper 11, which is arranged between the first input shaft 10 and the first clutch 2. The input of the damper 11 is power connected to the first input shaft 10, thereby being connectable to the crankshaft of the internal combustion engine 1, and the output of the damper 11 is power connected to the first rotary part 21 of the first clutch 2. The damper is preferably a torsional damper. However, the type of damper is not limited and can be other types of dampers, such as a hydraulic damper.

[0055] Preferably, the transmission mechanism can include a housing to accommodate one or more components of the transmission mechanism. Preferably, the internal combustion engine 1 and the motor generator 4 can be located outside the housing and on opposite sides of the housing, respectively. The housing can be fixed to a frame of the electric vehicle, for example. In the case where the transmission mechanism is provided with a housing, the first input shaft 10 is rotatably supported in a wall on one side of the housing, and the second input shaft 12 is rotatably supported in a wall on the other side of the housing opposite to the one side. The engine 1 is located on the one side, and the motor generator 4 is located on the other side, for example. The damper 11 and the reduction device 3 can be provided inside or outside the housing. The first clutch 2 is preferably provided inside the housing. The differential 7 is preferably provided inside the housing. One of the two output shafts 71 is rotatably supported in a wall on one side of the housing, and the other output shaft is rotatably supported in a wall on the other side of the housing. It should be understood that the positional relationship of all components of the transmission mechanism relative to the housing is not restrictive, but can be appropriately selected according to actual needs. The configuration of the housing is not limited, and the housing can not have any wall in the axial direction of the input shaft and / or the output shaft, for example.

[0056] The layout of the components of the transmission mechanism for an electric vehicle according to the above-described structure is rational, compact, facilitates assembly, saves space, and improves the utilization rate of the in-vehicle space. In particular, the reduction device 3 according to the present disclosure can decelerate the rotational output of the power source in a simple configuration and in a stable manner, and the second clutch 6 according to the present disclosure can quickly disconnect the power transmission of the drive device to the wheels of the electric vehicle.

[0057] Second Embodiment:

[0058] Figure 3 is a configuration diagram of a transmission mechanism, a range extender, and a range extending system for an electric vehicle according to the second embodiment. The same parts as those of the first embodiment of the second embodiment have the same reference numerals and the description thereof is omitted here, and only the different parts are described.

[0059] In the above-described first embodiment, as shown in Figure 1 , the second clutch 6 is located on the intermediate shaft 222 and is provided between the first intermediate gear 24 and the second intermediate gear 25. Unlike the first embodiment, as shown in Figure 3 , in the second embodiment, the second clutch 6 is provided on one of the two output shafts 71. Thereby, the power transmission from the differential 7 to the other end portion of either output shaft 71 can be disconnected. It should be understood that the same effect of disconnecting the power transmission can be achieved when the second clutch 6 is provided on either of the two output shafts 71.

[0060] Third Embodiment

[0061] Figure 4 is a configuration diagram of a transmission mechanism, a range extender, and a range extending system for an electric vehicle according to the third embodiment. Figure 5 is a diagram of a state when a first input gear, a ring gear, a first transition gear, and a second transition gear of a transmission mechanism according to the third embodiment are engaged. The same parts as those of the first embodiment of the third embodiment have the same reference numerals and the description thereof is omitted here, and only different parts are described.

[0062] In the above-described first embodiment, as shown in Figure 2 , the first input gear 32 is engaged with the inner teeth 331 of the ring gear 33 on the side of the ring gear 33 close to the first intermediate gear 24. Unlike the first embodiment, in the third embodiment, as shown in Figures 4-5 , the first input gear 32 is engaged with the inner teeth 331 of the ring gear 33 on the side of the ring gear 33 away from the first intermediate gear 24.

[0063] Specifically, in the third embodiment, the reduction device 3 includes the first transition gear 34 and the second transition gear 35 in addition to the first input gear 32. The center point of the first transition gear 34 and the center point of the second transition gear 35 are fixed respectively. The first transition gear 34 and the second transition gear 35 are located on the radially inner side of the ring gear 33 and can be fixed independently. However, preferably, the first transition gear 34 and the second transition gear 35 can be supported by a common gear carrier 36 which is fixed, for example, to the stator 42 of the electric motor 4. The first transition gear 34 is provided between the first input gear 32 and the second transition gear 35 and engaged with the first input gear 32 and the second transition gear 35 respectively, and the second transition gear 35 is engaged with the inner teeth 331 of the ring gear 33. As Figure 5 clearly shown, the first input gear 32 is on the side of the ring gear 33 away from the first intermediate gear 24 (see Figure 4 ), and the second transition gear 35 is on the side of the ring gear 33 close to the first intermediate gear 24 and engaged with the inner teeth 331 of the ring gear 33.

[0064] The size and arrangement of the first input gear 32, the first transition gear 34, and the second transition gear 35 are not particularly limited, as long as the three gears, i.e., the first input gear 32, the first transition gear 34, and the second transition gear 35, are in meshing engagement, the first input gear 32 and the second transition gear 35 are in meshing engagement with the inner teeth 331 of the ring gear 33, respectively. However, preferably, the center points of the first input gear 32, the ring gear 33, the first transition gear 34, the second transition gear 35, and the first intermediate gear 24 (not shown), i.e., the gear centers, are arranged on a straight line L, as shown in Figure 5 Thus, the radial force on the ring gear can be better balanced.

[0065] Thus, when power is transmitted from the first input gear 32 to the first intermediate gear 24 via the ring gear 33, by causing the meshing point of the second transition gear 35 with the ring gear 33, specifically the inner teeth 331, and the meshing point of the first intermediate gear 24 with the ring gear 33, specifically the outer teeth 332, to substantially overlap in the radial direction of the ring gear 33, the force on the ring gear is counteracted. Accordingly, the reduction device according to the present disclosure can reduce the rotational output of the driving source in a simple configuration and in a stable manner. Thus, the cost is further reduced.

[0066] Fourth Embodiment:

[0067] Figure 6 is a structural schematic diagram of a transmission mechanism, a range extender, and a range extending system for an electric vehicle according to the fourth embodiment. The same parts of the fourth embodiment as the third embodiment have the same reference numerals and the description thereof is omitted here, and only the different parts are described.

[0068] In the above-described third embodiment, as shown in Figure 4 the second clutch 6 is located on the intermediate shaft 222 and is provided between the first intermediate gear 24 and the second intermediate gear 25. Unlike the third embodiment, in the fourth embodiment, as shown in Figure 6 the second clutch 6 is provided on one of the two output shafts 71. Thus, the transmission of power from the differential 7 to the other end portion of any one of the output shafts 71 can be disconnected. It should be understood that the same effect of disconnecting the transmission of power can be achieved when the second clutch 6 is provided on any one of the two output shafts 71.

[0069] The range extender for an electric vehicle according to the present disclosure includes the transmission mechanism according to any one of the above-described first to fourth embodiments and the motor generator 4. The second input shaft 12 of the transmission mechanism for an electric vehicle is in power connection with the motor generator 4.

[0070] The motor generator 4 can function as both a motor and a generator. The motor generator 4 is provided with an inverter (not shown) for controlling the operation of the motor generator 4. The motor generator is preferably a permanent magnet synchronous motor (PSM). However, it should be understood that the type of the motor generator 4 is not limited.

[0071] The range extending system for an electric vehicle according to the present disclosure includes the above-described range extending device and the internal combustion engine 1. The first input shaft 10 of the transmission mechanism for the electric vehicle is power connected with the internal combustion engine 1, in particular, the crankshaft thereof. The specific type of the internal combustion engine 1 is not limited, for example, can be an in-line four-cylinder internal combustion engine, a horizontally opposed six-cylinder internal combustion engine, and a V-type 12-cylinder internal combustion engine, etc. The output parameters of the internal combustion engine, for example, the maximum torque, the maximum output power, etc. are also not limited, but are selected as needed. Thus, the internal combustion engine 1 and the motor generator 4 can together provide power to the output shaft 71 of the range extending system. However, it is readily understood that the internal combustion engine 1 can be limited to provide mechanical power to the output shaft 71, while only the motor generator 4 is maintained to provide power to the output shaft 71 to ensure the pure electric mode of the range extending system.

[0072] The range extending device and / or the range extending system in the prior art generally uses two electric machines, one of which is exclusively used for power generation and the other of which is exclusively used for driving to achieve the range extending function. This makes the device bulky and increases the cost. However, the range extending device and / or the range extending system described above according to the present disclosure only needs one electric machine, i.e., the motor generator 4, to achieve both the power generation and the driving functions of the vehicle, thereby achieving the range extending function with low cost and low space occupation. Moreover, the use of the reduction device 3 according to the present disclosure can reduce the rotational output of the power source in a simple structure and in a stable manner, and the use of the second clutch 6 according to the present disclosure can quickly disconnect the power transmission of the driving device to the output shaft or the wheels of the electric vehicle.

[0073] The electric vehicle according to the present disclosure includes the above-described range extending system, the power battery, and a pair of wheels 8, which are a pair of front wheels or a pair of rear wheels of the electric vehicle. The other end of each of the two output shafts of the transmission mechanism for the electric vehicle is power connected with a corresponding one of the pair of wheels 8. The electric power generated by the range extending system can be stored in the power battery of the electric vehicle. The range extending system according to the present disclosure can be the only driver of the electric vehicle. Thus, the efficient power generation and driving of the electric vehicle can be achieved without the need for additional drivers. Thus, the cost is reduced.

[0074] However, it is easily understood that the range extending system according to the present disclosure can be used as an auxiliary drive of an electric vehicle. Thereby, additionally, the electric vehicle of the present disclosure can comprise a main drive. The main drive comprises a main drive motor and a main reduction gear in power connection with the main drive motor. The main drive is used to drive a pair of wheels different from the pair of wheels 8 driven by the range extending system for the electric vehicle. For example, the range extending system according to the present disclosure can be used to drive a pair of front wheels of the electric vehicle, while the main drive can be used to drive a pair of rear wheels of the electric vehicle. Since the main drive itself is able to realize two-wheel drive of the electric vehicle, thereby the electric vehicle of the present disclosure is able to easily realize four-wheel drive of the electric vehicle by means of the range extending system.

[0075] With the range extending device and / or range extending system of the electric vehicle having the above structure, the damper can be easily mounted to the internal combustion engine, high power density and good smoothness are realized, and the entire range extending device and / or range extending system is highly integrated and compact, thereby realizing low resistance loss when the electric vehicle is coasting.

[0076] <Control strategy>

[0077] The range extending system for the electric vehicle according to the first embodiment has a plurality of working modes, including a pure electric mode, a hybrid drive mode, a first range extending mode and a second range extending mode, and can automatically realize switching of the plurality of modes according to a state of charge (SOC) of a power battery and a speed demand. Thereby, the present disclosure further provides a method of controlling the range extending system for the electric vehicle, the method comprising: a step S21 of judging a size relationship between the SOC of the power battery of the electric vehicle and an SOC threshold value, or simultaneously judging the size relationship between the SOC of the power battery of the electric vehicle and the SOC threshold value and a size relationship between a speed of the electric vehicle and a speed threshold value; and a step S22 of selecting a working mode of the range extending system according to a judgment result.

[0078] Figure 7 A comparison diagram of the SOC and the speed with respective threshold values is shown. As Figure 7 shown, the SOC threshold value comprises three threshold values, i.e. a first SOC threshold value S1, a second SOC threshold value S2 less than the first SOC threshold value S1, and a third SOC threshold value 3 less than the second SOC threshold value S2. According to the relationship between the SOC of the power battery of the electric vehicle and each of the SOC threshold values S1, S2 and S3 and the relationship between the speed V and the speed threshold value V1, the working mode of the range extending system is selected.

[0079] In particular, when the step S21 judges that the SOC of the power battery of the electric vehicle is higher than the first SOC threshold S1, the step S22 includes: controlling the internal combustion engine 1 to be inoperative and the motor generator 4 to operate as a drive motor, the first clutch 2 to be disengaged and the second clutch 6 to be engaged, the power from the motor generator 4 to be transmitted to the differential 7 via the reduction mechanism 3, the first intermediate gear 24 and the second intermediate gear 25, and then to the pair of wheels 8 to drive the electric vehicle. At this time, the range extending system for the electric vehicle operates in a pure electric mode. At this time, the main drive (if any, not shown) of the electric vehicle is usually used to drive another pair of wheels of the electric vehicle different from the pair of wheels 8. Therefore, when the range extending system for the electric vehicle operates in the pure electric mode, the electric vehicle can achieve four-wheel drive.

[0080] When the step S21 judges that the SOC of the power battery is lower than the first SOC threshold S1 but higher than the second SOC threshold S2, and the vehicle speed V is higher than the vehicle speed threshold V1, the step S22 includes: controlling the internal combustion engine 1 to operate and the motor generator 4 to operate as a drive motor, the first clutch 2 and the second clutch 6 to be engaged, the power of the internal combustion engine 1 and the power of the motor generator 4 to be coupled via the reduction mechanism 3, and then the coupled power to be transmitted to the differential 7 via the first intermediate gear 24 and the second intermediate gear 25, and then to the pair of wheels 8. At this time, the range extending system for the electric vehicle operates in a hybrid mode. At this time, the main drive (if any, not shown) of the electric vehicle is usually used to drive another pair of wheels of the electric vehicle different from the pair of wheels 8. Therefore, when the range extending system for the electric vehicle operates in the hybrid mode, the electric vehicle achieves four-wheel drive.

[0081] When the step S21 judges that the SOC of the power battery is lower than the second SOC threshold S2 but higher than the third SOC threshold S3, and the vehicle speed V is higher than the vehicle speed threshold V1, the step S22 includes: controlling the internal combustion engine 1 to operate and the motor generator 4 to operate as a generator, the first clutch 2 and the second clutch 6 to be engaged, a part of the power of the internal combustion engine 1 to be transmitted to the motor generator 4 to generate electricity via the first clutch 2 and the reduction mechanism 3, and another part of the power of the internal combustion engine 1 to be transmitted to the pair of wheels 8 via the first clutch 2, the reduction mechanism 3, the first intermediate gear 24, the second intermediate gear 25 and the differential 7. The electricity generated by the motor generator 4 is stored in the power battery (not shown) of the electric vehicle. At this time, the range extending system for the electric vehicle operates in a first range extending mode. At this time, the main drive (if any, not shown) of the electric vehicle is usually used to drive another pair of wheels of the electric vehicle different from the pair of wheels 8. Therefore, when the range extending system for the electric vehicle operates in the first range extending mode, the electric vehicle also achieves four-wheel drive.

[0082] When the step S21 judges that the SOC of the power battery is lower than the third SOC threshold S3 and the vehicle speed is lower than the vehicle speed threshold V1, the step S22 includes: controlling the first clutch 2 to be closed and the second clutch 6 to be opened, and the internal combustion engine 1 drives the motor generator 4 via the first clutch 2 and the reduction mechanism 3 to generate electricity to charge the power battery. At this time, the range extending system for the electric vehicle operates in the second range extending mode, in which only electricity generation is performed (pure electricity generation mode). The electricity generated by the motor generator 4 is stored in the power battery (not shown) of the electric vehicle. At this time, if the main drive (if any, not shown) of the electric vehicle is driving another pair of wheels of the electric vehicle different from the pair of wheels 8, when the range extending system for the electric vehicle operates in the second range extending mode, the electric vehicle travels in the low speed region in a two-wheel drive mode.

[0083] Further, when the range extending system starts, the motor generator 4 can be used as a driving motor to start the internal combustion engine 1. Accordingly, the method of controlling the range extending system of the electric vehicle of the present embodiment further includes: a step S23 of controlling the motor generator 4 to generate a starting torque and starting the internal combustion engine 1 when the range extending system starts.

[0084] In the above-mentioned first range extending mode and the second range extending mode, since the SOC of the power battery is low, the internal combustion engine 1 drives the motor generator 4 to charge the power battery to quickly raise the SOC of the power battery.

[0085] The above-mentioned various SOC thresholds are used to judge the SOC of the power battery, and the vehicle speed threshold is used to judge the vehicle speed. In the present embodiment, the specific values of the SOC thresholds and the vehicle speed threshold are not limited. Generally, they can be freely set according to a specific control strategy, and the values of any one of the SOC thresholds and the vehicle speed threshold are not the same under different control strategies. After the various SOC thresholds and the vehicle speed threshold are set, the electric vehicle can automatically judge and automatically switch between the various modes according to the judgment result.

[0086] In addition, when the vehicle brakes, the first clutch 2 is opened, and the second clutch 6 is closed to use the motor generator 4 to generate a braking torque to brake the wheels, so that an induced current will be generated in the winding of the motor generator 4 to charge the power battery of the electric vehicle, realizing the recovery of braking energy. Thus, the control method of the present embodiment further includes: controlling the second clutch 6 to generate a braking torque and generating an induced current in the winding of the motor generator 4 to charge the power battery of the electric vehicle when braking.

[0087] In addition, the range extending system for the electric vehicle according to the above-mentioned structure can disconnect both the internal combustion engine and the motor generator from the wheels 8 of the electric vehicle by simply opening the second clutch 6, so that the transmission of the driving force of the range extending system can be easily interrupted.

[0088] The various working modes of the range extending system for the electric vehicle are described above in connection with the first embodiment. The various working modes of the range extending system for the electric vehicle according to the second to fourth embodiments include the working states of the various components and the directions of the power flow, which are corresponding to the various working modes of the first embodiment. Therefore, the various working modes of the range extending system for the electric vehicle according to the second to fourth embodiments are not described in detail again. It should be understood that the above working modes are not restrictive, but can be modified as needed.

[0089] In addition, the present disclosure also provides a computer readable medium, for example, a program carrier such as a hard disk, comprising a program containing a plurality of instructions, wherein when the program runs on the vehicle-mounted computer, the instructions execute the method of controlling the range extending system for the electric vehicle.

[0090] The preferred embodiments of the present disclosure have been described above, but these embodiments are not intended to limit the scope of the present utility model. Therefore, various modifications can be made to the embodiments without exceeding the scope of protection defined by the claims of the present utility model, without deviating from the spirit and essential characteristics of the present utility model and its equivalents.

Claims

1. A transmission mechanism for an electric vehicle, characterized by comprises: a first input shaft (10); a second input shaft (12); a first clutch (2) provided between the first input shaft (10) and the second input shaft (12), the first clutch having a first rotary member (21) and a second rotary member (22) capable of being engaged and disengaged from each other, the first rotary member (21) of the first clutch being connected to the first input shaft (10); a reduction device (3) provided between the first clutch (2) and the second input shaft (12), the reduction device (3) including a first input gear (32) and a ring gear (33) having internal teeth (331) on a radially inner surface of the ring gear and external teeth (332) on a radially outer surface of the ring gear, the first input gear (32) being connected to the second input shaft (12) on one hand and being in mesh with the internal teeth (331) on the other hand, and the ring gear (33) being connected to the second rotary member (22) of the first clutch (2), whereby power from the first input shaft (10) and power from the second input shaft (12) can be coupled at the ring gear (33); a differential (7) provided with a second input gear (70) on a differential housing; an intermediate shaft (222); a first intermediate gear (24) and a second intermediate gear (25) arranged on the intermediate shaft (222), the first intermediate gear (24) being in mesh with the external teeth (332) of the ring gear (33), and the second intermediate gear (25) being power connectable with the first intermediate gear (24) on one hand and with the second input gear (70) of the differential (7) on the other hand, whereby the second input gear (70) is power connectable with the ring gear (33); two output shafts (71), one end of each of the two output shafts being power connected with the differential (7), whereby power from the differential (7) can be transmitted; and a second clutch (6) provided between the first intermediate gear (24) and the other end of each of the two output shafts opposite to the one end in a power transmission path of the transmission mechanism, whereby power transmission between the first intermediate gear (24) and the other end of each of the output shafts can be allowed or interrupted.

2. The transmission mechanism for an electric vehicle according to claim 1, characterized in that, in a radial direction of the ring gear (33), a meshing point of the first input gear (32) with the internal teeth (331) of the ring gear (33) and a meshing point of the first intermediate gear (24) with the external teeth (332) of the ring gear (33) overlap.

3. The transmission mechanism for an electric vehicle according to claim 1 or 2, characterized in that, The first input gear (32) meshes with the inner teeth (331) of the ring gear (33) on a side of the ring gear (33) close to the first intermediate gear (24).

4. The transmission mechanism for an electric vehicle according to claim 1 or 2, characterized in that, The first input gear (32) meshes with the inner teeth (331) of the ring gear (33) on a side of the ring gear (33) away from the first intermediate gear (24), and The reduction device (3) further includes a first stationary transition gear (34) and a second stationary transition gear (35), the first transition gear (34) is arranged between and meshes with the first input gear (32) and the second transition gear (35) respectively, and the second transition gear (35) meshes with the inner teeth (331) of the ring gear (33).

5. The transmission mechanism for an electric vehicle according to claim 4, characterized in that, Gear centers of the first input gear (32), the ring gear (33), the first transition gear (34), the second transition gear (35) and the first intermediate gear (24) are arranged on a straight line (L).

6. The transmission mechanism for an electric vehicle according to claim 1 or 2, characterized in that, The second clutch (6) is a dog clutch.

7. The transmission mechanism for an electric vehicle according to claim 1 or 2, characterized in that, The first clutch (2) is a friction clutch.

8. The transmission mechanism for an electric vehicle according to claim 6, characterized in that, The first clutch (2) is a friction clutch.

9. The transmission mechanism for an electric vehicle according to claim 1 or 2, characterized in that, The second clutch (6) is arranged between the first intermediate gear (24) and the second intermediate gear (25), thereby capable of allowing or disconnecting the transmission of power between the first intermediate gear (24) and the second intermediate gear (25).

10. The transmission mechanism for an electric vehicle according to claim 1 or 2, characterized in that, The second clutch (6) is arranged on any one of the two output shafts (71), thereby capable of disconnecting the transmission of power between the differential (7) and the other end.

11. The transmission mechanism for an electric vehicle according to claim 1 or 2, characterized by, The transmission mechanism further includes: A damper (11) arranged between the first input shaft (10) and the first clutch (2), an input end of the damper (11) is power connected with the first input shaft (10), and an output end of the damper (11) is power connected with a first rotating part (21) of the first clutch (2).

12. The transmission for an electric vehicle of claim 11, wherein, The damper (11) is a torsional damper.

13. A range extending device for an electric vehicle, characterized in that Comprise: A motor generator (4); and The transmission mechanism for an electric vehicle according to any one of the preceding claims 1-12, Wherein, a second input shaft (12) of the transmission mechanism is power connected with the motor generator (4).

14. The range extending device for an electric vehicle of claim 13, wherein, The motor generator is a permanent magnet synchronous motor.

15. A range extending system for an electric vehicle, characterized by Comprising: An internal combustion engine (1); A range extending device for an electric vehicle according to the preceding claim 13 or 14, wherein a first input shaft (10) of the transmission mechanism is power connected with the internal combustion engine (1).

16. The range extending system for an electric vehicle of claim 15, wherein, The internal combustion engine is an in-line 4-cylinder internal combustion engine.

17. An electric vehicle characterized by Comprising: A range extending system for an electric vehicle according to claim 15 or 16; A power battery in which electric power emitted by the range extending system is stored; and A pair of wheels (8), which is a pair of front wheels or a pair of rear wheels of the electric vehicle, wherein the other end of each of the two output shafts of the transmission mechanism for an electric vehicle is power connected with a respective one of the pair of wheels (8).

18. The electric vehicle of claim 17, wherein Comprising: A main drive including a main drive motor and a main speed reducer power connected with the main drive motor, the main drive being powered by a power battery of the electric vehicle, wherein the main drive is used to drive a pair of wheels of the electric vehicle different from the pair of wheels (8) driven by the range extending system for an electric vehicle.

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