Transmission assembly of electric drive apparatus, electric drive apparatus and vehicle

Abstract

The present disclosure provides a transmission assembly of an electric drive apparatus, an electric drive apparatus and a vehicle. The transmission assembly comprises: an electric motor main shaft which has a first end and a second end in a longitudinal axial direction; a first bearing and a second bearing which are arranged on the electric motor main shaft, respectively at the first end and the second end, to rotatably support the electric motor main shaft in an electric motor housing of the electric drive apparatus; and a transmission gear which is rotatably fixedly arranged on the electric motor main shaft and is closer to the first end than the second end. The transmission gear is located between the first bearing and the second bearing. In the transmission assembly, the transmission gear is arranged between two angular contact ball bearings, and therefore the transmission assembly has better NVH performance and a lower risk of misalignment, and the structure is simple and easy to assemble.

Description

[0001] Transmission assembly of electric drive apparatus, electric drive apparatus and vehicle

[0002] Technical Field

[0003] The present disclosure relates to a transmission assembly of an electric drive apparatus, an electric drive apparatus and a vehicle.

[0004] Background

[0005] As an important constituent part of a new energy vehicle, a portion of an electric drive apparatus, i.e. an electric motor shaft, may have a cantilever design. In a cantilever configuration, an input gear is located at an extremity of a drive end of the electric motor shaft. Generally, in a cantilever electric motor, two deep groove ball bearings are installed, and multiple components are used to aid the installation of the deep groove ball bearings. A deep groove ball bearing that is near the input gear or near the drive end of the electric motor shaft is fixed by means of a snap ring or a cover plate. A deep groove ball bearing that is remote from the input gear or near the non-drive end of the electric motor shaft is installed with the aid of a wave spring.

[0006] This type of configuration has some defects; for example, due to the cantilever, a portion of the cantilever that contains a gear has large deflection, and pressure deformation of the input gear is greater, and hence there is a risk of misalignment of the gearset and the cantilever structure. These defects worsen system NVH (noise, vibration and harshness) performance, and sideband frequencies even occur.

[0007] In addition, this type of configuration results in more complicated installation, not only comprising steps for installing various auxiliary components, but also comprising a step for fixing a non-drive end bearing inside an electric motor housing, thereby also increasing costs.

[0008] Therefore, a transmission assembly and an electric drive apparatus that can avoid the abovementioned defects is needed in this field. Summary of the Invention

[0009] Therefore, an object of the present disclosure lies in providing a transmission assembly of an electric drive apparatus, an electric drive apparatus and a vehicle, the transmission assembly has better NVH performance and a lower risk of misalignment, and the structure is simple and easy to assemble.

[0010] The abovementioned object is achieved through the transmission assembly of an electric drive apparatus, the electric drive apparatus and the vehicle which are described below.

[0011] The present disclosure provides a transmission assembly of an electric drive apparatus, the transmission assembly comprising: an electric motor main shaft, which has a first end and a second end in a longitudinal axial direction; a first bearing and a second bearing, which are arranged on the electric motor main shaft, respectively at the first end and the second end, to rotatably support the electric motor main shaft in an electric motor housing of the electric drive apparatus; and a transmission gear, which is rotatably fixedly arranged on the electric motor main shaft and is closer to the first end than the second end, wherein the transmission gear is located between the first bearing and the second bearing. The above non-cantilever type configuration reduces pressure deformation of the transmission gear, preventing installation misalignment, thereby improving NVH performance of the apparatus, and even preventing the occurrence of sideband frequencies.

[0012] The transmission assembly according to the present disclosure may also have one or more of the following features, alone or in combination.

[0013] In an embodiment, the first bearing and the second bearing are angular contact ball bearings, and in particular the first bearing and the second bearing are respectively single angular contact ball bearings.

[0014] In an embodiment, a wide edge of an outer ring of the first bearing is oriented toward an extremity of the first end of the electric motor main shaft, and a wide edge of an outer ring of the second bearing is oriented toward an extremity of the second end of the electric motor main shaft.

[0015] In an embodiment, in the longitudinal axial direction, the wide edge of the outer ring of the second bearing abuts the electric motor housing; the speed reducer housing of the electric drive apparatus exerts pressure toward the wide edge of the outer ring of the first bearing in the longitudinal axial direction.

[0016] The angular contact ball bearings paired with the non-cantilever type configuration can avoid the use of additional auxiliary installation components, reducing the number of components, and further reducing the installation steps; therefore, the structure is simple and easy to assemble, and the NVH performance is better.

[0017] In an embodiment, an adjustment shim is provided between the wide edge of the outer ring of the first bearing and the speed reducer housing.

[0018] In an embodiment, an adjustment shim is provided between the wide edge of the outer ring of the second bearing and the electric motor housing.

[0019] By means of the adjustment shim, the bearings can be preloaded, and may be adapted to different speed reducer housing inner wall forms, or adapted to different electric motor housing inner wall forms, and the bearing installation is enabled to adapt to different installation spaces, thereby improving the rigidity of the shaft system, and improving system flexibility.

[0020] In an embodiment, an inner ring of the first bearing abuts a first shoulder of the electric motor main shaft in the longitudinal axial direction, and an inner ring of the second bearing abuts a second shoulder of the electric motor main shaft in a direction opposite to the longitudinal axial direction. Thus two angular contact ball bearings may be used to install the transmission assembly, reducing the number of components, and simplifying installation.

[0021] In an embodiment, the transmission assembly further comprises a ratchet wheel, the ratchet wheel being arranged between the transmission gear and the first bearing, or the ratchet wheel being arranged between the transmission gear and the second bearing. The non-cantilever design of the present disclosure facilitates arrangement of the ratchet wheel, and the overall apparatus is stabler, worsening of NVH performance in a cantilever design is avoided, and the flexibility is greater.

[0022] In an embodiment, the transmission gear is integrally formed with the electric motor main shaft. In this way, deformation of the gear caused by pressure may be prevented, and costs may be reduced.

[0023] In an embodiment, the transmission assembly further comprises a gear set, and the gear set meshes with the transmission gear.

[0024] The present disclosure further provides an electric drive apparatus, comprising the transmission assembly as described above.

[0025] The present disclosure further provides a vehicle, comprising the transmission assembly or the electric drive apparatus as described above.

[0026] Brief Description of the Drawings

[0027] A better understanding of the advantages and objectives of the present disclosure can be gained from the preferred embodiments of the present disclosure described in detail below with reference to the drawings. To better illustrate the relationships among components in the drawings, the drawings are not drawn to scale. In the drawings:

[0028] Fig. 1 shows a schematic drawing of a transmission assembly of an electric drive apparatus for a vehicle according to an embodiment of the present disclosure;

[0029] Fig. 2 shows a schematic drawing of a portion of an electric drive apparatus according to an embodiment of the present disclosure;

[0030] Fig. 3 shows a schematic drawing of an interior of a non-drive end of the electric drive apparatus according to Fig. 2;

[0031] Fig. 4 shows a schematic drawing of an interior of a drive end of the electric drive apparatus according to Fig. 2;

[0032] Fig. 5 shows a sectional view of an electric drive apparatus according to an embodiment of the present disclosure;

[0033] Fig. 6 shows a sectional view of an electric drive apparatus according to another embodiment of the present disclosure;

[0034] Fig. 7 shows a schematic drawing of a transmission assembly according to another embodiment of the present disclosure; and

[0035] Fig. 8 shows a schematic drawing of a transmission assembly according to another embodiment of the present disclosure.

[0036] Detailed Description of Embodiments

[0037] In order to clarify the objective, the technical solution and the advantages of the present disclosure, the technical solution of embodiments of the present disclosure is described clearly and completely below in conjunction with the drawings accompanying particular embodiments of the present disclosure. In the drawings, identical reference numerals denote identical components. It must be explained that the embodiments described are some, not all, of the embodiments of the present disclosure. All other embodiments obtained by those skilled in the art based on the described embodiments of the present disclosure without the need for inventive effort shall fall within the scope of protection of the present disclosure.

[0038] Unless otherwise defined, the technical or scientific terms used herein shall have the common meanings understood by those skilled in the art. The words “first”, “second”, and the like used in the description and claims of the patent application disclosed herein do not indicate any order, quantity or importance, being merely used to distinguish different component parts. Likewise, words such as “a” or “one” do not necessarily represent a quantity limit. Words such as "comprising", "including” or "having" mean that the element or object preceding the word covers the elements or objects listed after the word and equivalents thereof, without excluding other elements or objects. Words such as "connection” or "communication”, rather than being limited to the physical or mechanical connection or communication shown in a drawing, may include connection or communication equivalent thereto, irrespective of whether it is direct or indirect. The terms “upper”, “lower”, “left”, “right” and the like are only used to indicate a relative positional relationship, and when the absolute position of a described object changes, the relative positional relationship may also change accordingly.

[0039] Embodiments of the present disclosure are described in detail below with reference to Figs. 1 - 8.

[0040] Fig. 1 shows a transmission assembly of an electric drive apparatus according to the present disclosure, and Fig. 2 shows at least a portion of an electric drive apparatus according to the present disclosure; the electric drive apparatus, for example, is used for converting electrical energy into mechanical energy to drive a vehicle to move, and comprises an electric motor, a controller and a speed reducer, the transmission assembly shown in Fig. 1 being used for the electric motor. Generally, the electric motor, the controller and the speed reducer are integrated into a whole; the controller is not shown in Fig. 2. As shown in Fig. 2, the electric drive apparatus comprises an electric motor housing 8 and a speed reducer housing 7 that can be fixedly connected to each other, an electric motor and a speed reducer being arranged in an accommodating cavity that is formed by the electric motor housing 8 and the speed reducer housing 7, and the speed reducer housing 7 is fixedly connected to an end (namely a drive end of an electric motor main shaft) of the electric motor housing 8 by means of a bolt, and may be called a “casing of the speed reducer” or a “speed reducer end cover”. For example, the electric motor housing 8 may comprise a housing main body 81 and an electric motor end cover 82, and, as shown in Fig. 3, the housing main body 81 has an approximately cylindrical form for example, but of course other forms are also possible; the electric motor end cover 82 is located at a non-drive end of the electric motor main shaft and is opposite the speed reducer end cover, and may be fixedly connected to the housing main body 81 by means of a bolt. The speed reducer is connected to the electric motor main shaft by means of a gear set, and torque output by the electric motor main shaft is transferred to a vehicle wheel of a vehicle by a differential of the speed reducer after passing through the gear set, so as to be able to drive the whole vehicle to move.

[0041] As shown in Fig. 1, the transmission assembly for an electric drive apparatus of the present disclosure comprises an electric motor main shaft 1, a first bearing 5, a second bearing 6 and a transmission gear 4 (also called an “input gear”). In addition, the electric motor further comprises a stator and a rotor. The rotor is fixed to the electric motor main shaft 1 and rotates together therewith, and is formed by stacking multiple iron cores, and the rotor iron cores are internally provided with magnet mounting holes in which permanent magnets are inserted. The stator also comprises a stator iron core formed by multiple metal laminations (e.g. silicon steel plates), and is provided with multiple stator teeth and multiple stator slots separated by the stator teeth, and a winding is wound through the stator slots. The stator iron core has a roughly tubular structure, with the rotor accommodated therein. As an example, windings are able to generate a rotating magnetic field when supplied with three-phase alternating current, thereby generating electromagnetic torque to drive the rotor to rotate. The electric drive apparatus of the present disclosure may be arranged in a vehicle, and the vehicle may be an electrified vehicle as described below, such as a battery electric vehicle (BEV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), a range extended EV or a fuel cell electric vehicle (FCEV), or may be a hydrogen vehicle.

[0042] Again referring to Fig. 1, the electric motor main shaft 1 has a first end 2 and a second end 3 in a longitudinal axial direction X; the first bearing 5 is arranged on the electric motor main shaft 1 at the first end 2, and the second bearing 6 is arranged on the electric motor main shaft 1 at the second end 3, thereby rotatably supporting the electric motor main shaft 1 in the electric motor housing 8; the transmission gear 4 is rotatably fixedly arranged on the electric motor main shaft 1 and is closer to the first end 2 than the second end 3. The transmission gear 4 is located between the first bearing 5 and the second bearing 6. The first end 2 described above is also called the “electric motor drive end”, and the second end 3 is also called the “electric motor non-drive end”. As shown in Fig. 2, the speed reducer housing 7 is arranged at the first end 2 of the electric motor main shaft 1. The longitudinal axial direction X, for example, is a horizontal leftward direction in Fig. 1, i.e. pointing from the electric motor drive end to the electric motor non-drive end.

[0043] The above configuration is of a non-cantilever type, reducing pressure deformation of the transmission gear, preventing installation misalignment, and also preventing large deflection of a cantilever portion, thereby improving NVH performance of the apparatus, and even preventing the occurrence of sideband frequencies. As shown in Figs. 3 to 5, the first bearing 5 and the second bearing 6 are both angular contact ball bearings. For example, the first bearing 5 and the second bearing 6 are respectively single angular contact ball bearings, which may also be called “single-row angular contact ball bearings”. Each angular contact ball bearing comprises an outer ring, an inner ring, a roller and a retaining frame; multiple rollers, such as balls, by means of the retaining frame, are installed between the outer ring and the inner ring at a certain distance from each other. The single-row angular contact ball bearing can only endure a load in one direction along an axis, i.e. the longitudinal axial direction X in Fig. 1. In addition, the outer ring and the inner ring both comprise a wide edge and a narrow edge, i.e. an edge of a larger size and an edge of a smaller size in a direction perpendicular to the axis.

[0044] As shown in Fig. 5, a wide edge of an outer ring 51 of the first bearing 5 is oriented toward an extremity of the first end 2 of the electric motor main shaft 1 , and a wide edge of an outer ring 61 of the second bearing 6 is oriented toward an extremity of the second end 3 of the electric motor main shaft 1. That is, the first bearing 5 and the second bearing 6 are paired in opposite directions.

[0045] In addition, in the longitudinal axial direction X of the electric motor shaft 1, the wide edge of the outer ring 61 of the second bearing 6 abuts the electric motor housing 8, and the speed reducer housing 7 exerts pressure toward the wide edge of the outer ring 51 of the first bearing 5 in the longitudinal axial direction X of the electric motor main shaft 1. For example, the wide edge of the outer ring 61 of the second bearing 6 may abut an electric motor end cover 82 of the electric motor housing 8, i.e. an inner wall of the electric motor end cover 82 on the left in Fig. 5.

[0046] As shown in Fig. 5, a first shoulder 11 and a second shoulder 12 are provided on the electric motor main shaft 1, the two both extending in a ring along the circumference of the electric motor main shaft 1. An inner ring 52 of the first bearing 5 abuts a first shoulder 11 of the electric motor main shaft 1 in the longitudinal axial direction X of the electric motor main shaft 1, and an inner ring 62 of the second bearing 6 abuts a second shoulder 12 of the electric motor main shaft 1 in a direction opposite to the longitudinal axial direction X of the electric motor main shaft 1.

[0047] In this way, the electric motor main shaft 1 may press the second bearing 6 on the electric motor housing 8, such as on the electric motor end cover 82, by means of the second shoulder 12 of the electric motor main shaft 1, and the speed reducer housing 7 presses the first bearing 5 on the first shoulder 11 of the electric motor main shaft 1, thereby achieving assembly by means of exerting pressure in the longitudinal axial direction X.

[0048] As shown in Fig. 1, an outer side of the outer ring 51 of the first bearing 5 is provided with an adjustment shim 9; in other words, as shown in Fig. 5, the adjustment shim 9 is provided between the wide edge of the outer ring 51 of the first bearing 5 and the speed reducer housing 7. The adjustment shim 9 may be a conventional form in the art.

[0049] In another embodiment as shown in Fig. 6, an outer side of the outer ring 61 of the second bearing 6 is provided with an adjustment shim 9; in other words, the adjustment shim 9 is provided between the wide edge of the outer ring 61 of the second bearing 6 and the electric motor housing 8. For example, an adjustment shim 9 is provided between the wide edge of the outer ring 61 of the second bearing 6 and the electric motor end cover 82 (or the inner wall of the electric motor end cover).

[0050] By means of the adjustment shim 9, the first bearing 5 and the second bearing 6 can be preloaded; the first bearing 5 may be adapted to inner wall forms of different speed reducer housings 7, or the second bearing 6 may be adapted to inner wall forms of different electric motor housings 8, and the bearing installation is enabled to adapt to different installation spaces, such as an installation length in the longitudinal axial direction X of the electric motor main shaft 1, thereby improving the rigidity of the shaft system, and improving system flexibility.

[0051] As shown in Fig. 4, at a first end 2 of the electric motor main shaft 1, the transmission assembly of the present disclosure further may comprise a gearset 10, and the gearset 10 meshes with the transmission gear 4. In addition, the gearset 10 further meshes with a differential of the speed reducer, and thus may transfer torque output by the electric motor main shaft 1 to a vehicle wheel of a vehicle.

[0052] As shown in Figs. 7 and 8, the transmission assembly further comprises a ratchet wheel 13, and the ratchet wheel 13 is mounted on the electric motor main shaft 1, and is mechanically connected to a parking locking mechanism of a vehicle, to realize a parking function. As shown in Fig. 7, the ratchet wheel 13 may be arranged between the transmission gear 4 and the first bearing 5. As shown in Fig. 8, the ratchet wheel 13 may be arranged between the transmission gear 4 and the second bearing 6, specifically between the transmission gear 4 and a stator and rotor on the electric motor main shaft 1. The non-cantilever design of the present disclosure facilitates arrangement of the ratchet wheel, and the overall apparatus is stabler, worsening of NVH performance in a cantilever design is avoided, and the flexibility is greater.

[0053] The transmission gear 4 may be integrally formed with the electric motor main shaft 1. For example, the transmission gear 4 may be integrally formed with the electric motor main shaft 1 by means of forging. In this way, deformation of the gear caused by pressure may be prevented, and costs may be reduced. Of course, the transmission gear 4 may also be connected to the electric motor main shaft 1 by means of interference fit with a spline or a shaft hole.

[0054] In addition, the ratchet wheel 13 may also be integrally formed with the electric motor main shaft 1. For example, the ratchet wheel 13 may be integrally formed with the electric motor main shaft 1 by means of forging. In this way, the transmission gear, the ratchet wheel and the electric motor main shaft may form a single component, not only simplifying installation and reducing costs, but also allowing the option of a smaller bearing size due to a higher load capacity of the angular contact ball bearings used. Of course, the ratchet wheel 13 may also be connected to the electric motor main shaft 1 by means of interference fit with a spline or a shaft hole.

[0055] Below, a brief explanation is given of how to install the transmission assembly of the present disclosure in the electric drive apparatus. Firstly, the second bearing 6 is mounted on the electric motor main shaft 1 ; the electric motor main shaft 1 is already fitted with components such as a stator, rotor, etc. Next, the electric motor main shaft 1 is installed in the electric motor housing 8, and also may be mounted on the electric motor end cover 82 of the electric motor housing 8. After this, the first bearing 5 is mounted on the electric motor main shaft 1, and then the gearset 10 and the adjustment shim 9 are installed. Finally, the speed reducer housing 7 is mounted on the electric motor housing 8 (i.e. the housing main body 81). It can be seen that neither the transmission assembly nor the electric drive apparatus of the present disclosure requires the installation of many auxiliary components, nor requires additional bearing fixation, and therefore the installation steps are significantly reduced.

[0056] As described above, a non-cantilever configuration is used for the transmission assembly of the present disclosure; a transmission gear is arranged between a first bearing and a second bearing, which reduces the distance between the centre of a rotor of the electric motor (i.e. a central position of the electric motor main shaft) and the centre of the transmission gear, such that gear deflection during coasting or driving of a vehicle is significantly reduced, and deflection of the rotor centre is also reduced compared to a cantilever configuration. In addition, the transmission assembly of the present disclosure only uses two angular contact ball bearings and one shim, reducing the number of components, and further reducing installation steps, and therefore the structure is simple and easy to assemble. Further, the transmission assembly of the present disclosure has higher shaft system rigidity, a lower risk of misalignment and better NVH performance. The electric drive apparatus of the present disclosure comprises the transmission assembly as described above, and therefore has the abovementioned advantages of the transmission assembly.

[0057] Another aspect of the present disclosure proposes a vehicle, comprising the transmission assembly according to any one of the above embodiments, or the electric drive apparatus as described above. According to an embodiment, this vehicle is an electrified vehicle, such as a battery electric vehicle (BEV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), a range extended EV or a fuel cell electric vehicle (FCEV). The vehicle may also be a hydrogen vehicle. The vehicle of the present disclosure therefore also has the abovementioned advantages of the transmission assembly.

[0058] In addition, the technical features disclosed above are not limited to combinations of the disclosed features with other features, and those skilled in the art could combine technical features in other ways according to the objective of the invention, to realize the objective of the present disclosure.

Claims

Claims1. A transmission assembly of an electric drive apparatus, the transmission assembly comprising: an electric motor main shaft (1), which has a first end (2) and a second end (3) in a longitudinal axial direction (X); a first bearing (5) and a second bearing (6), which are arranged on the electric motor main shaft (1), respectively at the first end (2) and the second end (3), to rotatably support the electric motor main shaft (1) in an electric motor housing (8) of the electric drive apparatus; and a transmission gear (4), which is rotatably fixedly arranged on the electric motor main shaft (1) and is closer to the first end (2) than the second end (3), wherein the transmission gear (4) is located between the first bearing (5) and the second bearing (6).

2. The transmission assembly according to claim 1, wherein the first bearing (5) and the second bearing (6) are angular contact ball bearings, and in particular the first bearing (5) and the second bearing (6) are respectively single angular contact ball bearings.

3. The transmission assembly according to claim 2, wherein a wide edge of an outer ring (51) of the first bearing (5) is oriented toward an extremity of the first end (2) of the electric motor main shaft (1), and a wide edge of an outer ring (61) of the second bearing (6) is oriented toward an extremity of the second end (3) of the electric motor main shaft (1).

4. The transmission assembly according to claim 3, wherein in the longitudinal axial direction (X), the wide edge of the outer ring (61) of the second bearing (6) abuts the electric motor housing (8); a speed reducer housing (7) of the electric drive apparatus exerts pressure toward the wide edge of the outer ring (51) of the first bearing (5) in the longitudinal axial direction (X).

5. The transmission assembly according to claim 4, wherein an adjustment shim (9) is provided between the wide edge of the outer ring (51) of the first bearing (5) and the speed reducer housing (7).

6. The transmission assembly according to claim 3, wherein an adjustment shim (9) is provided between the wide edge of the outer ring (61) of the second bearing (6) and the electric motor housing (8).

7. The transmission assembly according to claim 3, wherein an inner ring (52) of the first bearing (5) abuts a first shoulder (11) of the electric motor main shaft (1) in the longitudinal axial direction (X), and an inner ring (62) of the second bearing (6) abuts a second shoulder (12) of the electric motor main shaft (1) in a direction opposite to the longitudinal axial direction (X).

8. The transmission assembly according to any one of claims 1 to 7, wherein the transmission assembly further comprises a ratchet wheel (13), the ratchet wheel (13) being arranged between the transmission gear (4) and the first bearing (5), or the ratchet wheel (13) being arranged between the transmission gear (4) and the second bearing (6).

9. The transmission assembly according to any one of claims 1 to 7, wherein the transmission gear (4) is integrally formed with the electric motor main shaft (1).

10. The transmission assembly according to any one of claims 1 to 7, wherein the transmission assembly further comprises a gear set (10), and the gear set meshes with the transmission gear (4).

11. An electric drive apparatus, comprising the transmission assembly according to any one of claims 1 to 10.

12. A vehicle, comprising the transmission assembly according to any one of claims 1 to 10, or the electric drive apparatus according to claim 11.

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