Single-motor two-gear coaxial electric drive axle structure, vehicle and method

Abstract

The invention discloses a single-motor two-gear coaxial electric drive axle structure, a vehicle and a working method, solves the problems of mass center offset and large occupied space of an electric drive axle in the prior art, and has the beneficial effects of being compact in structure, high in integration level and convenient to arrange. Comprising a first half shaft and a second half shaft, the first half shaft and the second half shaft are connected through a differential mechanism, a driving motor is arranged around the first half shaft and is a hollow shaft motor, an output shaft of the driving motor is connected with a first planet row, and a first planet carrier in the first planet row is fixedly connected with driving discs of at least two clutches; driven discs of the clutches are fixedly connected with sun gears in the second planet row respectively, the sun gears are meshed with the corresponding planet gears, one planet gear is meshed with the corresponding gear ring, all the planet gears in the second planet row are connected and arranged on the second planet carrier in a sleeved mode, and the first planet row and the second planet row both take the first half shaft as the rotation center.

Description

Technical Field

[0001] The present invention relates to the field of electric drive technology, and in particular to a single-motor two-speed coaxial electric drive axle structure, a vehicle, and a method. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] With the rapid development of new energy vehicles, electric drive technology is increasingly being used in the automotive sector. In the commercial vehicle sector, pure electric heavy-duty trucks typically utilize either a central drive or an electric axle drive system for vehicle power transmission. While the central drive system requires minimal changes to the vehicle, offers low development difficulty and a short development cycle, it also has significant disadvantages, such as large chassis space occupation, long power transmission routes, low efficiency, and reduced safety. Consequently, many newly developed models are adopting the electric axle drive system.

[0004] In the currently disclosed technologies, there are parallel-axis and coaxial electric drive axles. The parallel-axis electric drive axle is an arrangement in which the motor and transmission system are offset to one or both sides of the bridge to form a mass center load. Although this arrangement is relatively easy to manufacture, it occupies a large space. Moreover, for heavy-duty commercial vehicles, in order to enhance load capacity and reliability, it is often necessary to design a double intermediate shaft structure, so the weight also increases, which is not conducive to lightweight design. Moreover, the mass center load arrangement is very demanding on the shell strength, affecting the reliability and lightweight design of the electric drive axle. Although the coaxial electric drive axle has no mass center load, due to the relatively high speed requirements of heavy trucks and the complex structural settings, at least three levels of deceleration are generally required, resulting in a large axial dimension of the existing coaxial electric drive axle, and it is currently less used.

[0005] The prior art discloses a coaxial two-speed electric drive axle, which includes a drive motor coaxially arranged with the axle, and an intermediate shaft and gears arranged on the shaft offset to one side of the axle. Two-speed drive is achieved through a shift mechanism on the intermediate shaft. Although the motor is coaxially arranged, the two-speed reduction gear and the intermediate shaft are still offset. For the electric drive axle, the greater the offset mass, the greater the eccentricity of the center of mass, and the greater the impact load transmitted from the road on the electric drive axle, which is prone to problems such as fatigue failure of the electric drive axle and shell rupture.

[0006] Moreover, the above scheme only has two levels of parallel gear reduction, which cannot achieve a larger speed ratio; In addition, a single intermediate shaft is provided on the outside of the half-shaft, but the structural load-bearing capacity of the single intermediate shaft is limited and it cannot be used for heavy trucks. Summary of the Invention

[0007] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a single-motor two-speed coaxial electric drive bridge structure with a compact structure, high integration, small component volume and weight, and high power density.

[0008] In order to achieve the above object, the present invention is implemented through the following technical solutions: A single-motor two-speed coaxial electric drive axle structure includes a first half-shaft and a second half-shaft, the first half-shaft and the second half-shaft are connected by a differential, a drive motor is arranged around the first half-shaft, the drive motor is a hollow shaft motor, the output shaft of the drive motor is connected to the first planetary row, the first planetary carrier in the first planetary row is fixedly connected to the driving plates of at least two clutches, the driven plates of each clutch are respectively fixedly connected to the sun gear in the second planetary row, the sun gear is meshed with the corresponding planetary gear, one of the planetary gears is meshed with the corresponding ring gear, all the planetary gears in the second planetary row are connected and sleeved on the second planetary carrier, the first planetary row and the second planetary row both use the first half-shaft as the rotation center, and different second planetary rows are formed according to the engagement conditions of different clutches to adjust the reduction ratio of the electric drive axle.

[0009] As described above, in a single-motor two-speed coaxial electric drive axle structure, the first planetary gear includes a first sun gear fixed to the output shaft of the drive motor, the first sun gear is externally meshed with the first planetary gear, the first planetary gear is internally meshed with the first ring gear, the first ring gear is fixed, and several first planetary gears are idling in the first planetary carrier.

[0010] As described above, in a single-motor two-speed coaxial electric drive axle structure, the gear ratios of each sun gear and the corresponding planet gear in the second planetary gear set are different, so that different reduction ratios can be achieved in conjunction with the first planetary gear set.

[0011] As described above, a single-motor two-speed coaxial electric drive bridge structure, the clutch includes a first clutch, the driven plate of the first clutch is fixedly connected to the third sun gear in the second planetary row, the third sun gear is externally meshed with the third planetary gear, the third planetary gear is internally meshed with the second ring gear, and the second ring gear is fixed.

[0012] The single-motor two-speed coaxial electric drive axle structure described above, wherein the clutch further comprises a second clutch, wherein the driven plate of the second clutch is fixedly connected to the second sun gear of the second planetary gear, the second sun gear is externally meshed with the second planetary gear, the second planetary gear is fixedly connected to the third planetary gear to form a stepped gear, the stepped gear is loosely mounted on the second planetary carrier, and the second planetary carrier is fixed to the differential; Taking into account the transmission of power and the arrangement of structural space, the second clutch and the second sun gear are arranged between the first clutch and the third sun gear.

[0013] As described above, in a single-motor two-speed coaxial electric drive axle structure, the length of the first half-shaft is greater than the length of the second half-shaft, so that the first planetary gear and the second planetary gear are arranged on the longer first half-shaft, ensuring the rationality of the electric drive axle structure setting and the balance of mass.

[0014] As described above, in a single-motor two-speed coaxial electric drive bridge structure, the first planetary carrier is connected to the coupling sleeve, the coupling sleeve can be connected to the sun gear in the second planetary row, and the coupling sleeve can transmit the power transmitted by the first planetary row to the second sun gear or the third sun gear in the second planetary row.

[0015] In a second aspect, the present invention further discloses a vehicle, comprising the single-motor two-speed coaxial electric drive axle structure.

[0016] In a third aspect, a method for operating a single-motor two-speed coaxial electric drive axle structure includes the following: The power output by the drive motor is reduced in one stage by the first planetary gear, output through the first planetary carrier, and then transmitted to the active plate of the clutch; When the vehicle starts or climbs a slope, one of the clutches engages and the other disengages, and power is transmitted to one of the sun gears of the second planetary gear set, passing through the NW planetary gear set consisting of the corresponding planetary gear, ring gear and planetary carrier to achieve the first reduction ratio.

[0017] As described above, in the working method of a single-motor two-speed coaxial electric drive bridge structure, when the vehicle is traveling at high speed, the working clutch is disengaged and the other clutch is engaged, and the power is transmitted to the other sun gear of the second planetary gear, and the second reduction ratio is achieved through the NGW planetary gear composed of the corresponding planetary gear, ring gear and planetary carrier.

[0018] The beneficial effects of the present invention are as follows: 1) The present invention is provided with an electric drive axle structure, and the rotation centers of the drive motor, the first planetary gear, and the second planetary gear are all the rotation center of the first semi-shaft, that is, the three are coaxially arranged with the drive axle, i.e., the first semi-shaft. The theoretical center of mass is coaxial with the first semi-shaft. There is no cantilever structure, and there will be no center of mass offset. This effectively improves the force and vibration conditions, effectively reduces the impact of the impact load transmitted from the road surface on the electric drive axle, minimizes the fatigue failure of the electric drive axle, and is conducive to the overall lightweight design.

[0019] 2) The present invention provides a clutch or coupling sleeve between the first planetary gear and the second planetary gear, so that different planetary gears can be formed in the second planetary gear. Through the operation of different clutches or coupling sleeves, the different planetary gears in the first planetary gear and the second planetary gear can achieve a larger speed ratio by realizing two-stage reduction without the need for three-stage reduction. This effectively reduces the number of parts, has a compact structure, effectively controls the overall occupied space, and has a high power density.

[0020] 3) The overall structure of the present invention is rationally arranged. The first planetary gear and the second planetary gear are both along the axial direction of the first semi-shaft. The drive motor and each sun gear are arranged on the first semi-shaft, which makes the overall size small, facilitates the layout of the entire vehicle, and ensures the load-bearing capacity of the overall structure, and can be used in heavy trucks.

[0021] 4) The second planetary gear set structure in the present invention is reasonably arranged, and the positions of the second sun gear and the third sun gear in the second planetary gear set are reasonably arranged, which not only facilitates the connection with the corresponding clutch, but also facilitates power transmission. In addition, all the planetary gears in the second planetary gear set are connected and loosely mounted on the corresponding second planetary carrier, eliminating the need for additional ring gears.

[0022] 5) The electric drive axle structure of the present invention can achieve power shifting through dual-clutch shifting, which further improves the power, safety, comfort and controllability of the vehicle under harsh working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0024] Figure 1 It is a schematic diagram of a single-motor two-speed coaxial electric drive bridge structure according to one or more embodiments of the present invention.

[0025] Figure 2 It is a schematic diagram of the working state of a single-motor two-speed coaxial electric drive axle structure when the vehicle is in first gear according to one or more embodiments of the present invention.

[0026] Figure 3 It is a schematic diagram of the working state of a single-motor two-speed coaxial electric drive axle structure when the vehicle is in the second gear according to one or more embodiments of the present invention.

[0027] Figure 4 It is a schematic diagram of the working state of a vehicle in first gear after the clutch is replaced by the coupling sleeve in a single-motor two-speed coaxial electric drive axle structure according to one or more embodiments of the present invention.

[0028] Figure 5 It is a schematic diagram of the working state of a vehicle in 2nd gear after the clutch is replaced by the coupling sleeve in a single-motor two-speed coaxial electric drive axle structure according to one or more embodiments of the present invention.

[0029] In the figure: the distances or sizes between parts are exaggerated to show the positions of various parts, and the schematic diagram is for reference only.

[0030] Among them: 1-drive motor; 2-first sun gear; 3-first ring gear; 4-first planetary gear; 5-first planetary carrier; C1-first clutch; C2-second clutch; 6-second sun gear; 7-third sun gear; 8-second planetary gear; 9-third planetary gear; 10-second ring gear; 11-second planetary carrier; 12-differential; 13-first half shaft; 14-wheel; 15-second half shaft; 16-joint sleeve. DETAILED DESCRIPTION

[0031] It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those skilled in the art to which the present invention belongs.

[0032] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless otherwise clearly indicated in the present invention, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "include" and / or "comprising" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or their combinations; As introduced in the background technology, the electric drive bridge in the prior art has the problems of uneven center of mass load, large space occupation and inconvenient layout. In order to solve the above technical problems, the present invention proposes a single-motor two-speed coaxial electric drive bridge structure.

[0033] Example 1 In a typical embodiment of the present invention, referring to Figure 1 As shown, a single-motor two-speed coaxial electric drive bridge structure includes a first half-shaft 13 and a second half-shaft 15, which are connected by a differential 12. A drive motor 1 is arranged around the first half-shaft 13, and the drive motor 1 is a hollow shaft motor. The output shaft of the drive motor 1 is connected to the first planetary gear. The first planetary carrier 5 in the first planetary gear is fixedly connected to the driving plates of at least two clutches, and the driven plates of each clutch are respectively fixedly connected to the sun gear in the second planetary gear. The sun gear is meshed with the corresponding planetary gear, and one of the planetary gears is meshed with the corresponding ring gear. All the planetary gears in the second planetary gear are connected and sleeved on the second planetary carrier 11. The first planetary gear and the second planetary gear both use the central axis of the first half-shaft 13 as the rotation center. Different second planetary gears are formed according to the engagement conditions of different clutches to adjust the reduction ratio of the electric drive bridge.

[0034] In the electric drive axle structure provided in this embodiment, the rotation centers of the drive motor 1, the first planetary gear and the second planetary gear are all the rotation centers of the first semi-shaft 13, that is, the three are coaxially arranged with the drive axle, i.e., the first semi-shaft 13. The theoretical center of mass is coaxial with the first semi-shaft 13, there is no cantilever structure, and there will be no center of mass offset, which effectively reduces the impact of the impact load transmitted from the road surface on the electric drive axle and minimizes the phenomenon of fatigue failure of the electric drive axle.

[0035] Among them, the length of the first half shaft 13 is greater than that of the second half shaft 15, so that the first planetary gear and the second planetary gear are arranged on the longer first half shaft 13, ensuring the rationality of the electric drive axle structure setting and the balance of mass. The second planetary carrier 11 is fixed to the differential 12.

[0036] In this embodiment, the first planetary gear set includes a first sun gear 2 fixed to the output shaft of the drive motor 1, the first sun gear 2 is fixedly connected to the output shaft of the drive motor 1, the first sun gear 2 is sleeved on the circumference of the first half shaft 13, and the first ring gear 3 is fixed; the first planetary gear 4 is externally meshed with the first sun gear 2 and internally meshed with the first ring gear 3; several first planetary gears 4 are loosely sleeved on the first planet carrier 5; the first sun gear 2, the first ring gear 3, the first planetary gear 4, and the first planet carrier 5 constitute the first planetary gear set.

[0037] It should be noted that the gear ratios of each sun gear and the corresponding planet gear in the second planetary gear set are different, so that different reduction ratios can be achieved in conjunction with the first planetary gear set.

[0038] Specifically, the clutch includes a first clutch C1 and a second clutch C2, the second planetary row includes a second sun gear 6 and a third sun gear 7, the first planetary carrier 5 is fixedly connected to the driving plates of the first clutch C1 and the second clutch C2; the driven plate of the first clutch C1 is fixedly connected to the third sun gear 7; the driven plate of the second clutch C2 is fixedly connected to the second sun gear 6; the second planetary gear 8 is externally meshed with the second sun gear 6; the third planetary gear 9 is externally meshed with the third sun gear 7 and internally meshed with the second ring gear 10; the second ring gear 10 is fixed so that the second ring gear 10 is stationary; the second planetary gear 8 and the third planetary gear 9 are fixedly connected to form a stepped gear, and several stepped gears are loosely mounted on the second planetary carrier 11; according to the meshing conditions of the first clutch C1 and the second clutch C2, the second sun gear 6, the third sun gear 7, the second planetary gear 8, the third planetary gear 9, the second ring gear 10 and the second planetary carrier 11 can form different second planetary rows.

[0039] In this way, different planetary gears can be formed in the second planetary gear. By selecting different clutches to work, the first planetary gear and the different planetary gears in the second planetary gear can achieve two-stage deceleration to achieve a larger speed ratio without the need for three-stage deceleration, effectively reducing the number of parts, making the structure compact and easy to install.

[0040] It is easy to understand that, considering the power transmission and the arrangement of the structural space, the second clutch C2 and the second sun gear 6 are arranged between the first clutch C1 and the third sun gear 7. In this way, the second clutch C2 and the second sun gear 6 are arranged nearby for easy arrangement.

[0041] The first ring gear 3 and the second ring gear 10 are fixed inside the housing, and the entire electric drive axle structure is arranged inside the housing.

[0042] In the electric drive axle structure provided by this embodiment, the positions of the second sun gear 6 and the third sun gear 7 in the second planetary row are reasonably arranged, which not only facilitates the connection with the corresponding clutch, but also facilitates the transmission of power. In addition, all the planetary gears in the second planetary row are connected and loosely mounted on the corresponding second planetary carrier 11, and there is no need to set more ring gears; the first planetary row and the second planetary row are both along the axial direction of the first half shaft 13, and the drive motor and each sun gear are set on the first half shaft 13, so that the overall axial dimension is small, which is conducive to lightweight design and the overall vehicle structure layout. Compared with the single intermediate shaft structure set on the outside of the half shaft, it effectively guarantees the bearing capacity of the overall structure and can be used for heavy trucks.

[0043] Example 2 This embodiment discloses a working method of a single-motor two-speed coaxial electric drive bridge structure, including the following contents: The power output by the driving motor 1 is firstly reduced in one stage by the first planetary gear set consisting of the first sun gear 2, the first ring gear 3, the first planetary gear 4 and the first planetary carrier 5. The reduction ratio of the first planetary gear set is i PG1 for: i PG1 =Z3 / Z2+1 Among them, i PG1 is the reduction ratio of the first planetary gear; Z3 is the number of teeth of the first ring gear 3; Z2 is the number of teeth of the first sun gear 2.

[0044] After being decelerated by the first planetary gear, the power is output by the first planetary carrier 5 and transmitted to the driving plates of the first clutch C1 and the second clutch C2.

[0045] When the vehicle starts or climbs a slope, the required torque is large. At this time, the second clutch C2 is engaged, the first clutch C1 is disengaged, and the power is transmitted to the second sun gear 6. Figure 2 As shown, at this time, the vehicle is in the first gear, and the second planetary gear 6, the second planetary gear 8, the third planetary gear 9, the second ring gear 10, and the second planetary carrier 11 are composed of the second planetary gear NW (inner-outer) planetary gear, which can achieve a larger reduction ratio to meet the power requirements of the vehicle starting or climbing. The power is reduced in two stages by the second planetary gear. In the first gear, the reduction ratio of the second planetary gear is i PG2 'for: i PG2'=(Z 10 / Z9) · (Z8 / Z6)+1 Among them, i PG2 'When it is the 1st gear, the reduction ratio of the second planetary gear is Z 10 is the number of teeth of the second ring gear 10; Z9 is the number of teeth of the third planetary gear 9; Z8 is the number of teeth of the second planetary gear 8; and Z6 is the number of teeth of the second sun gear 6.

[0046] When the vehicle is in 1st gear, the total speed ratio i1 of the electric drive axle transmission system is: i1= i PG1 ·i PG2 ' When the vehicle is running at high speed, the first clutch C1 is engaged, the second clutch C2 is disengaged, and the power is transmitted to the third sun gear 7. Figure 3 As shown, at this time, the vehicle is in the second gear, and the second planetary gear consisting of the third sun gear 7, the third planetary gear 9, the second ring gear 10, and the second planetary carrier 11 is a NGW (inner-common-outer) planetary gear. In the second gear, the reduction ratio of the second planetary gear is i PG2 "The NW planetary row is relatively small, as follows: i PG2 ”=Z 10 / Z7+1 Wherein, Z7 is the number of teeth of the third sun gear 7; When the vehicle is in 2nd gear, the total speed ratio i2 of the electric drive axle transmission system is: i2= i PG1 ·i PG2 ” After being decelerated by the second planetary gearbox, the power is transmitted by the second planetary carrier 11 to the differential, the first half-shaft 13 , the second half-shaft 15 , and finally to the wheels 14 .

[0047] The vehicle controller controls the engagement and disengagement of clutch C1 and clutch C2 in real time according to road conditions and driver needs to achieve gear switching and ensure that the drive motor 1 always operates in the optimal high-efficiency area.

[0048] Example 3 The difference between this embodiment and the first embodiment is that: The first planet carrier is connected to the engagement sleeve 16, which can be connected to the second sun gear 6 or the third sun gear 7 in the second planetary row. Figure 4 As shown, when the vehicle is in 1st gear, the clutch can transmit the power transmitted by the first planetary gear to the second sun gear 6 in the second planetary gear, and then to the corresponding second planetary gear 8; Figure 5 As shown, when the vehicle is in the second gear, the clutch sleeve 16 can transmit the power transmitted by the first planetary gear to the third sun gear 7 in the second planetary gear, and then to the corresponding third planetary gear 9 after transmitting it to the third sun gear 7.

[0049] Example 4 This embodiment discloses a vehicle, including the single-motor two-speed coaxial electric drive axle structure described in the first or third embodiment.

[0050] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A single-motor two-speed coaxial electric drive bridge structure, characterized in that: The invention comprises a first half-shaft and a second half-shaft, which are connected via a differential. A drive motor is arranged around the first half-shaft, and the drive motor is a hollow shaft motor. The output shaft of the drive motor is connected to the first planetary row. The first planetary carrier in the first planetary row is fixedly connected to the driving plates of at least two clutches. The driven plates of each clutch are respectively fixedly connected to the sun gear in the second planetary row. The sun gear is meshed with the corresponding planetary gear, and one of the planetary gears is meshed with the corresponding ring gear. All the planetary gears in the second planetary row are connected and sleeved on the second planetary carrier. The first planetary row and the second planetary row both use the first half-shaft as the rotation center. Different second planetary rows are formed according to the meshing conditions of different clutches to adjust the reduction ratio of the electric drive axle.

2. A single-motor two-speed coaxial electric drive bridge structure according to claim 1, characterized in that: The first planetary gear includes a first sun gear fixed to the output shaft of the drive motor, the first sun gear is externally meshed with the first planetary gear, the first planetary gear is internally meshed with the first ring gear, the first ring gear is fixed, and a plurality of first planetary gears are loosely mounted on the first planet carrier.

3. The single-motor two-speed coaxial electric drive bridge structure according to claim 1, characterized in that: The gear ratios between the sun gear and the corresponding planet gear in the second planetary gear set are different.

4. The single-motor two-speed coaxial electric drive bridge structure according to claim 1, characterized in that: The clutch includes a first clutch, a driven plate of the first clutch is fixedly connected to the third sun gear in the second planetary row, the third sun gear is externally meshed with the third planetary gear, the third planetary gear is internally meshed with the second ring gear, and the second ring gear is fixed.

5. The single-motor two-speed coaxial electric drive bridge structure according to claim 4, characterized in that: The clutch further includes a second clutch, wherein the driven plate of the second clutch is fixedly connected to the second sun gear in the second planetary gear row, the second sun gear is externally meshed with the second planetary gear, the second planetary gear is fixedly connected to the third planetary gear to form a stepped gear, the stepped gear is loosely mounted on the second planetary carrier, and the second planetary carrier is fixed to the differential; The second clutch and the second sun gear are arranged between the first clutch and the third sun gear.

6. The single-motor two-speed coaxial electric drive axle structure according to claim 1, characterized in that: The length of the first semi-axis is greater than the length of the second semi-axis.

7. The single-motor two-speed coaxial electric drive axle structure according to claim 1, characterized in that: The first planet carrier is connected to a clutch sleeve, and the clutch sleeve can be connected to the sun gear in the second planetary gear set.

8. A vehicle, characterized in that: A single-motor two-speed coaxial electric drive bridge structure comprising any one of claims 1-7.

9. A method for operating a single-motor two-speed coaxial electric drive bridge structure according to any one of claims 1 to 6, characterized in that: Includes the following: The power output by the drive motor is reduced in one stage by the first planetary gear, output through the first planetary carrier, and then transmitted to the active plate of the clutch; When the vehicle starts or climbs a slope, one of the clutches engages and the other disengages, and power is transmitted to one of the sun gears of the second planetary gear set, passing through the NW planetary gear set consisting of the corresponding planetary gear, ring gear and planetary carrier to achieve the first reduction ratio.

10. The operating method of a single-motor two-speed coaxial electric drive bridge structure according to claim 9, characterized in that: When the vehicle is traveling at high speed, the working clutch disengages and the other clutch engages, and the power is transmitted to the other sun gear of the second planetary gear set, and then passes through the NGW planetary gear set composed of the corresponding planetary gear, ring gear and planetary carrier to achieve the second reduction ratio.

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