Electrically-driven axle assembly and electric vehicle

Abstract

The invention relates to an electrically-driven axle assembly and an electric vehicle, and the electrically-driven axle assembly comprises a modularized pre-assembled power unit which pre-assembles a motor, a motor controller, a speed reducer and a differential into an integral module, the integral module is integrally assembled on an axle, and a motor shaft of the motor and a first-stage gear shaft of the speed reducer form an integral shaft; and the tank oil lubricating and cooling system comprises a motor cooling oil way and a transmission mechanism lubricating oil way which are formed on the axle housing and the modularized preassembled power unit, are communicated with each other through oil ways and share a single oil chamber. According to the invention, by integrating modularized pre-installed units and sharing a single lubricating oil chamber, parts are simplified, the oil use amount is reduced, the assembly weight is reduced by about 10%, the use amount of bearings and shaft seals is reduced, the system reliability is improved, and the maintenance cost is effectively reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to new energy vehicles, in particular to an electric drive axle assembly. Furthermore, the present application also relates to an electric vehicle. BACKGROUND

[0002] The electric drive axle develops towards high power density and light weight, and the oil-cooled motor gradually replaces the water-cooled motor, but the existing scheme has problems such as lubrication system redundancy and complex assembly.

[0003] Specifically, in the prior art, due to the inertial cognition of the traditional design idea, the mainstream axle drive product adopts a two-tank oil scheme, that is, one tank of oil is used for motor cooling, and one tank of oil is used for axle differential and reducer, the motor cooling oil and the reducer lubricating oil are independent, which brings inconvenience to use and maintenance, resulting in complex oil management and weight increase. In addition, the motor and the reducer are assembled separately, and independent shaft seals and bearings are required, which increases friction loss and NVH (Noise, Vibration and Harshness) problems.

[0004] That is, the above-mentioned prior art defects are: first, the two-tank oil scheme increases the oil filling amount and maintenance cost, and the oil compatibility is poor; second, the spline cooperation between the motor and the reducer produces additional vibration noise; third, the separate assembly requires additional shaft seals and bearings, which increases the weight and reduces the reliability, and the transmission efficiency is reduced by 3%-5%.

[0005] Therefore, it is necessary to design a new electric drive axle assembly. SUMMARY

[0006] The technical problem to be solved by the present application is to provide an electric drive axle assembly and an electric vehicle, which can solve or alleviate at least one of the above-mentioned defects.

[0007] In order to solve the above-mentioned technical problem, the present application provides an electric drive axle assembly, which comprises: a modular pre-assembled power unit, the modular pre-assembled power unit comprising a motor, a motor controller, a reducer and a differential pre-assembled as a whole module, and the modular pre-assembled power unit is assembled on an axle, wherein a motor shaft of the motor and a primary gear shaft of the reducer are formed as an integrated shaft; and a one-tank oil lubrication and cooling system, a cooling and lubricating oil circuit of the one-tank oil lubrication and cooling system comprising a motor cooling oil circuit and a transmission mechanism lubricating oil circuit formed on an axle housing and the modular pre-assembled power unit and communicated by an oil circuit, the motor cooling oil circuit and the transmission mechanism lubricating oil circuit sharing a single oil chamber.

[0008] Specifically, the integrated shaft is supported by a three-bearing structure, and the three-bearing structure comprises a motor end bearing, an auxiliary support bearing and a reducer end bearing.

[0009] Preferably, the integrated shaft is a hollow shaft with preset rigidity, and the motor is a motor with preset stack length, the integrated shaft is supported by two bearing structures, the two bearing structures include a motor end bearing and a reducer end bearing.

[0010] Preferably, a primary pinion of a primary gear pair of the reducer is integrally formed on a shaft wall of the hollow shaft.

[0011] In some embodiments, the one-tank oil lubrication cooling system includes an oil pump, a coarse filter, a fine filter and a heat exchanger, a cooling lubricating oil circuit of the one-tank oil lubrication cooling system sequentially passes through a stator core cooling oil channel of the motor, a stator end cooling oil channel, a rotor cooling oil channel, each bearing lubrication point and a gear lubrication point of the transmission mechanism.

[0012] Typically, the motor is an oil-cooled motor, and the stator core cooling oil channel is an axial flow channel.

[0013] Optionally, the reducer is a two-stage reducer including a primary gear pair and a secondary gear pair, and is connected to the differential in a power transmission manner.

[0014] Specifically, the modular pre-installed power unit is assembled on the axle, and half shafts in the axle are connected to an output end of the differential.

[0015] Preferably, the motor in the modular pre-installed power unit is connected to a mounting cavity of the reducer, so that a shaft seal and an end cover are not arranged to reduce friction pairs.

[0016] Based on the above-mentioned various schemes of the electric drive axle assembly, the application further provides an electric vehicle, which is provided with the above-mentioned electric drive axle assembly.

[0017] In the technical scheme of the above-mentioned electric drive axle assembly, the reducer and the differential are first integrated and installed with the motor and the motor controller as a modular pre-installed power unit, and then the whole module is assembled with the axle, and the motor shaft and the primary gear shaft of the reducer adopt an integrated shaft, so that spline cooperation is cancelled, the cost and weight are reduced, and the NVH is improved.

[0018] The actual test proves that, through the above technical scheme of the application, the electric drive axle assembly effectively reduces the friction pair, the transmission efficiency is improved by 3%-5%, in addition, through the integration of the modular pre-installation unit and the shared single lubricating oil chamber (and the hollow shaft design in the preferred mode), the components are simplified and the oil consumption is reduced, the total weight is reduced by about 10%, and the single oil product is used, which reduces the risk of shaft seal leakage, effectively reduces the maintenance cost.

[0019] Other advantages of the application and technical effects of the preferred embodiments will be further described in the specific embodiments below. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a structural schematic diagram of an integrated shaft three-bearing support mode adopted in some embodiments of the application, and the motor is not shown in the figure;

[0021] Figure 2 is a structural schematic diagram of an integrated shaft two-bearing support mode adopted in some optimized embodiments of the application, and the motor is not shown in the figure; and

[0022] Figure 3 is a principle structural schematic diagram of an oil tank lubrication cooling system in some embodiments of the application.

[0023] Figure 4 is a structural schematic diagram of an electric drive axle assembly in some embodiments of the application.

[0024] The application has the following reference signs:

[0025] 1 integrated shaft; 2 motor end bearing; 3 auxiliary support bearing; 4 reducer end bearing; 5 first-stage pinion; 6 first-stage gear; 7 second-stage pinion; 8 second-stage gear; 9 differential; 10 reducer first supporting bearing; 11 reducer second supporting bearing; 12 differential first supporting bearing; 13 differential second supporting bearing; 14 single oil chamber; 15 cooling lubricating oil path; 16 oil pump; 17 fine filter; 18 heat exchanger; 19 distributor; 20 motor cooling oil path; 21 transmission mechanism cooling oil path; 22 coarse filter; 23 hub; 24 axle housing; 25 modular pre-installation power unit. DETAILED DESCRIPTION

[0026] The specific embodiments of the application are described in detail below with reference to the accompanying drawings.

[0027] It should be understood that the description of the embodiments is only for the purpose of illustration and helps those skilled in the art to understand and implement the present disclosure, and does not impose any limitation on the scope of the present disclosure. The disclosure described herein can be implemented in a manner different from that described below.

[0028] In the following description and claims, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0029] Reference throughout this disclosure to "one embodiment", "an embodiment", "exemplary embodiment", or the like, means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily referring to the same embodiment.

[0030] Furthermore, although the terms "first" and "second" and the like can be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element without departing from the scope of the example embodiments. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed terms.

[0031] Reference throughout this disclosure to Figures 1 to 4 As shown, in the basic embodiment of the present application, the electric drive axle assembly of the present application comprises a modular pre-installed power unit and a one-tank oil lubrication cooling system, wherein the modular pre-installed power unit 25 comprises a motor, a motor controller, a reducer and a differential pre-installed as an integral module, and the modular pre-installed power unit 25 is assembled on the axle, wherein the motor shaft and the primary gear shaft of the reducer are formed as an integral shaft. The cooling lubrication oil circuit 15 of the one-tank oil lubrication cooling system comprises a motor cooling oil circuit 20 and a transmission mechanism lubrication oil circuit 21 formed on the axle housing 24 and the modular pre-installed power unit 25 and communicated by an oil circuit, and the motor cooling oil circuit 20 and the transmission mechanism lubrication oil circuit 21 share a single oil chamber 14.

[0032] In the above embodiment, the reducer, the differential and the motor, the motor controller are pre-integrated and installed as a modular pre-installed power unit, and the integral module is assembled with the axle, and the motor shaft and the primary gear shaft of the reducer (i.e. the primary driving gear shaft or the primary pinion shaft of the reducer) adopt an integral shaft 1, and the spline fit is cancelled, which reduces the cost and weight and improves the NVH. Moreover, the oil cooling motor cooling oil circuit and the lubrication oil circuit of the transmission mechanism (the reducer and the differential) of the electric drive axle are connected, and a one-tank cooling lubrication oil is shared, which improves the maintenance of the axle. Through the integrated modular pre-installed unit and the shared single lubrication oil chamber, the components are simplified and the oil consumption is reduced, and the total weight is reduced by about 10%, which effectively reduces the maintenance cost

[0033] It should be noted that the above embodiments of the present invention break through traditional conventional understanding by combining motor cooling oil and transmission mechanism lubricating oil into one. In order to make the oil meet the requirements of motor cooling and transmission mechanism lubrication, in actual use, the lubricating oil is generally a low sulfur content oil to meet the common needs of motor and transmission mechanism (reducer and differential, etc.).

[0034] Based on the above basic embodiments, see Figure 1 As shown, in some embodiments, the integrated shaft 1 is supported by a three-bearing structure, which may include a motor-end bearing 2, an auxiliary support bearing 3, and a reducer-end bearing 4. In this embodiment, the integrated shaft 1 is supported at three points, resulting in better stability.

[0035] In some optimized implementations, see [link to specific implementation]. Figure 2 As shown, the integrated shaft 1 can be supported by a two-bearing structure, which may include a motor-end bearing 2 and a reducer-end bearing 4. In this case, to adapt to the stability of the two-point support, the integrated shaft 1 can be a hollow shaft with a preset stiffness (generally a high-stiffness hollow shaft), and the motor is a motor with a predetermined stack length (generally a short-stacked motor with a shorter stack length). In this optimized embodiment, due to the use of a two-point support structure and the use of a hollow shaft for the integrated shaft 1, the weight can be further effectively reduced, and the number of bearings requiring lubrication is reduced, thereby improving system reliability.

[0036] In a further preferred embodiment, since the motor shaft and the primary gear shaft of the reducer are formed as a single unit, the primary pinion 5 (i.e., the primary drive gear) in the primary gear pair of the reducer can be directly machined onto the single unit shaft. For example, the primary pinion 5 in the primary gear pair of the reducer can be integrally formed on the shaft wall of the hollow shaft. This forming method further reduces the number of parts, lowers the weight, and contributes to the improvement of NVH performance.

[0037] See Figure 3 As shown, in some specific implementation embodiments, a tank oil lubrication and cooling system may include an oil pump 16, a coarse filter (i.e., an oil collector) 22, a fine filter 17, and a heat exchanger 18. The coarse filter 22 is disposed in a single oil chamber 14 (formed on the axle housing 24 of the axle). The cooling and lubrication oil passage 15 of the tank oil lubrication and cooling system passes through the stator core cooling oil passage, the stator end cooling oil passage, the rotor cooling oil passage, the lubrication points of each bearing, and the lubrication points of the transmission gear of the transmission mechanism, thereby cooling the motor and lubricating the transmission mechanism.

[0038] In some embodiments, the motor is an oil-cooled motor, and the stator core cooling oil channel is an axial flow channel, which is more conducive to cooling and improves cooling efficiency.

[0039] Typically, the reduction gear can be a two-stage reduction gear comprising a first-stage gear pair and a second-stage gear pair, and is drivingly connected to the differential 9. The first-stage gear pair comprises a first-stage pinion 5 and a first-stage gear 6, and the second-stage gear pair comprises a second-stage pinion 7 and a second-stage gear 8.

[0040] As to the specific installation form, in some embodiments, the modular pre-assembled power unit is assembled on the axle, specifically, the reduction gear is supported in the axle housing by a reduction gear first bearing 10 and a reduction gear second bearing 11, the differential 9 is supported in the axle housing by a differential first bearing 12 and a differential second bearing 13, and the axle shafts in the axle are connected to the output end of the differential 9. Further, the axle shafts are drivingly connected to the wheel hubs 23, which are subsequently used for mounting the wheels.

[0041] In some embodiments, the motor in the modular pre-assembled power unit can be connected to the installation cavity of the reduction gear, so that no shaft seal and independent end cover can be provided, which can reduce the friction pair and improve the power transmission efficiency.

[0042] On the basis of the above-mentioned various embodiments of the electrically driven axle, the application further provides an electric vehicle, which is installed with the electrically driven axle assembly of any of the above-mentioned embodiments.

[0043] The basic embodiments and various specific embodiments of the application are described above in a hierarchical manner, in order to help a more profound understanding of the application, the following refers to Figures 1 to 3 a more comprehensive and specific embodiment is described.

[0044] Referring to Figures 1 to 3 In this embodiment, the electrically driven axle assembly of the application adopts an integrated shaft structure: the motor shaft is coaxial with the reduction gear first-stage gear shaft, typically, the motor shaft and the reduction gear first-stage gear shaft can be formed into an integrated shaft 1 through integrated forging processing, which cancels the spline fit in the traditional way, adopts three-bearing or two-bearing support, which can at least reduce one bearing, two shaft seals, eliminate the spline vibration source, and improve the NVH performance. Further, by adopting a short-stacked long motor and a hollow integrated shaft 1 design, the auxiliary support bearing 3 can be cancelled, which not only further reduces the weight, but also improves the shaft stiffness.

[0045] Further, the electric drive axle assembly of the embodiment adopts a modular assembly, the motor, the motor controller, the reducer (including the differential 9), the cooling lubricating oil circuit, etc. are pre-assembled as an integral module, then connected with the axle, and finally the half shaft is installed. Specifically, the integral module can be connected with the axle housing through a flange, and the half shaft is finally inserted and connected to the differential output end. The installation mode of the modular pre-assembled power unit can effectively improve the assembly efficiency of the production line, shorten the assembly time, and the tolerance of the half shaft installation is enhanced, and the overall axial space occupation is reduced by about 25%.

[0046] In addition, the electric drive axle assembly of the embodiment adopts a one-tank oil lubrication cooling system, the cooling lubricating oil circuit 15 integrates the motor cooling and transmission mechanism lubrication functions, and the oil pump 16 drives the oil to circulate after double-stage filtration and heat exchange. Specifically, the one-tank oil lubrication cooling system can include an oil pump 16, a coarse filter (i.e. an oil collector) 22, a fine filter 17, and a heat exchanger 18, wherein the coarse filter 22 is arranged in a single oil chamber 14, the cooling lubricating oil circuit 15 draws oil from the single oil chamber 14 through the oil pump (3), passes through the coarse filter 22→the fine filter 17→the heat exchanger 18, and is then divided into two paths through the distributor 19:

[0047] The motor cooling oil circuit 20: the stator core, the stator end, the rotor, etc.

[0048] The transmission mechanism lubricating oil circuit branch 21: each bearing, reducer gear lubrication point, and differential lubrication point.

[0049] The one-tank oil lubrication cooling system reduces the oil filling amount of the axle assembly, and also facilitates use, maintenance, and repair, and reduces maintenance costs.

[0050] As can be seen from the above description, the application adopts an integrated shaft 1 integrating a motor shaft and a reducer primary gear shaft, and adopts a modular pre-assembled power unit module installation structure and a one-tank oil lubrication cooling system, which reduces the use of bearings and shaft seals, improves transmission efficiency by reducing friction pairs, reduces weight, and improves use and maintenance convenience by reducing lubricating oil chambers. Through actual tests, it has been confirmed that, by using the above technical solutions of the application, the electric drive axle assembly of the application effectively reduces the friction pairs, improves the transmission efficiency by 3%-5%, further, by integrating the modular pre-assembled unit and the single lubricating oil chamber, the components are simplified and the oil consumption is reduced, the total weight is reduced by about 10%, and the shaft seal leakage risk is reduced, effectively reducing the maintenance and repair costs.

[0051] The preferred embodiments of the application are described in detail above with reference to the drawings, but the application is not limited to the specific details in the above-described embodiments, and various simple modifications can be made to the technical solutions of the application within the technical concept of the application, and these simple modifications all belong to the protection scope of the application.

[0052] It should be further noted that each of the various technical features described in the above embodiments can be combined with any other technical features in any suitable manner, and the present application shall be deemed to disclose all possible combinations thereof, without causing unnecessary repetition.

[0053] Furthermore, any combination of the various embodiments of the present application can be made, as long as it does not deviate from the spirit of the present application, and it shall be deemed to be disclosed by the present application.

Claims

1. An electric drive axle assembly, characterized in that, include: A modular pre-installed power unit, comprising a motor, motor controller, reducer, and differential pre-installed as a single module, mounted on an axle, wherein the motor shaft of the motor and the primary gear shaft of the reducer are integrally formed; and A single-tank oil lubrication and cooling system, wherein the cooling and lubrication oil circuit of the single-tank oil lubrication and cooling system includes a motor cooling oil circuit and a transmission mechanism lubrication oil circuit formed on the axle housing and the modular pre-installed power unit and connected by the oil circuit, wherein the motor cooling oil circuit and the transmission mechanism lubrication oil circuit share a single oil chamber.

2. The electric drive axle assembly according to claim 1, characterized in that, The integrated shaft is supported by a three-bearing structure, which includes a motor end bearing, an auxiliary support bearing, and a reducer end bearing.

3. The electric drive axle assembly according to claim 1, characterized in that, The integrated shaft is a hollow shaft with a preset stiffness, and the motor is a motor with a predetermined stacked length. The integrated shaft is supported by a two-bearing structure, which includes a motor end bearing and a reducer end bearing.

4. The electric drive axle assembly according to claim 3, characterized in that, The hollow shaft has an integrally formed primary pinion of the primary gear pair of the reducer on its shaft wall.

5. The electric drive axle assembly according to claim 1, characterized in that, The single-tank oil lubrication and cooling system includes an oil pump, a coarse filter, a fine filter, and a heat exchanger. The cooling and lubrication oil circuit of the single-tank oil lubrication and cooling system passes through the stator core cooling oil channel, the stator end cooling oil channel, the rotor cooling oil channel, the lubrication points of each bearing, and the lubrication points of the transmission gears of the transmission mechanism.

6. The electric drive axle assembly according to claim 5, characterized in that, The motor is an oil-cooled motor, and the stator core cooling oil channel is an axial flow channel.

7. The electric drive axle assembly according to claim 1, characterized in that, The reducer is a two-stage reducer, which includes a primary gear pair and a secondary gear pair, and is connected to the differential in a transmission manner.

8. The electric drive axle assembly according to any one of claims 1 to 7, characterized in that, The modular pre-installed power unit is mounted on the axle, and the half-shafts within the axle are connected to the output end of the differential.

9. The electric drive axle assembly according to any one of claims 1 to 7, characterized in that, The motor in the modular pre-installed power unit is connected to the mounting chamber of the reducer, so as to reduce friction pairs by eliminating the need for shaft seals and end covers.

10. An electric vehicle, characterized in that, The electric vehicle is equipped with an electric drive axle assembly according to any one of claims 1 to 9.

Images