An electric drive assembly and an electric vehicle

Abstract

This application discloses an electric drive assembly and an electric vehicle, relating to the field of drive assembly technology. The electric drive assembly is a coaxial planetary gear electric drive assembly, comprising a housing, a motor, and a planetary gear reducer. The motor shaft is coaxially connected to the reducer shaft, and an output half-shaft is coaxially connected to the end of the motor shaft furthest from the reducer shaft. A half-shaft bearing is fitted onto the output half-shaft. A non-drive end bearing and a drive end bearing are fitted onto the motor shaft, and an input end bearing and an output end bearing are fitted onto the reducer shaft. The planetary gear reducer also includes a sun gear fitted onto the reducer shaft, multiple planet gears meshing with the sun gear, and a gear ring meshing with at least one planet gear. The gear ring is electrically connected to the housing. Insulation structures are provided between the half-shaft bearings and the housing, and between the non-drive end bearings and the housing. This application achieves the effect of protecting the half-shaft bearings and the non-drive end bearings while suppressing corrosion of other components in the electric drive assembly.

Description

Technical Field

[0001] This application relates to the field of drivetrain technology, and in particular to an electric drivetrain and an electric vehicle. Background Technology

[0002] In current drive motors, the influence of common-mode shaft voltage-corrosion-corrosion-corrosion-related currents on bearings is typically eliminated by shorting the shaft and housing with conductive elements. Insulating elements are also used to increase the impedance of the circulating shaft current loop to mitigate the impact of cyclic shaft currents on bearings. However, in electric drive assemblies, due to the presence of the reducer, there are usually multiple bearings at the drive end, resulting in multiple different cyclic shaft current loops. Improper application of conductive elements can reduce the impedance of the cyclic shaft current loop, increasing the harmful effects of cyclic shaft currents on bearings. In other words, inappropriate electro-corrosion suppression measures can actually increase the risk of electro-corrosion of bearings in electric drive assemblies.

[0003] Therefore, designing bearing electro-corrosion suppression schemes according to the configuration differences of different electric drive assemblies to effectively avoid damage to multiple bearings of the electric drive assembly caused by cyclic shaft current is an urgent technical problem to be solved. Utility Model Content

[0004] The main objective of this application is to provide an electric drive assembly and an electric vehicle, which aims to solve the technical problem in the related art where the bearing electro-corrosion suppression of electric drive assemblies cannot effectively prevent the cyclic shaft current from causing damage to multiple bearings.

[0005] To achieve the above objectives, this application proposes an electric drive assembly, which is a coaxial planetary gear electric drive assembly, comprising a housing and a motor and a planetary gear reducer disposed within the housing;

[0006] The motor includes a motor shaft, and the planetary gear reducer includes a reducer shaft. The motor shaft and the reducer shaft are coaxially connected. The end of the motor shaft furthest from the reducer shaft is also coaxially connected to an output half shaft. A half shaft bearing is fitted on the end of the output half shaft furthest from the motor shaft, and a non-drive end bearing is fitted on the end of the motor shaft closest to the output half shaft.

[0007] The half-shaft bearing is insulated from the housing, as is the non-drive end bearing from the housing.

[0008] In one embodiment, insulation is provided between the half-shaft bearing and the housing, and between the non-drive end bearing and the housing, including:

[0009] An insulating structure is provided between the axle bearing and the housing; the axle bearing is an insulated bearing; and / or an insulating structure is provided between the axle bearing and the output axle shaft; and...

[0010] An insulating structure is provided between the non-drive end bearing and the housing; the non-drive end bearing is an insulated bearing; and / or an insulating structure is provided between the non-drive end bearing and the motor shaft.

[0011] In one embodiment, the insulating structure between the axle bearing and the housing includes any one or more of the following: providing an insulating coating on the outer wall of the outer ring of the axle bearing, wrapping an insulating element around the outer wall of the outer ring of the axle bearing, and providing an insulating coating on the area of ​​the housing that contacts the axle bearing.

[0012] In one embodiment, the half-shaft bearing is an insulated bearing, which includes any one or more of the following: the rolling elements of the half-shaft bearing are ceramic balls and the cage is made of insulating material; an insulating coating is provided between the outer wall of the inner ring of the half-shaft bearing and the rolling elements; and an insulating coating is provided between the inner wall of the outer ring of the half-shaft bearing and the rolling elements.

[0013] In one embodiment, the insulating structure between the half-shaft bearing and the output half-shaft includes any one or more of the following: an insulating coating is provided on the area of ​​the output half-shaft that contacts the inner ring of the half-shaft bearing; an insulating sleeve is fitted on the area of ​​the output half-shaft that contacts the inner ring of the half-shaft bearing; and an insulating coating is provided on the inner wall of the inner ring of the half-shaft bearing.

[0014] In one embodiment, the insulating structure between the non-driving end bearing and the housing includes any one or more of the following: providing an insulating coating on the outer wall of the outer ring of the non-driving end bearing, wrapping an insulating element around the outer wall of the outer ring of the non-driving end bearing, and providing an insulating coating on the area of ​​the housing that contacts the non-driving end bearing.

[0015] In one embodiment, the non-drive end bearing is an insulated bearing, which includes any one or more of the following: the rolling elements of the non-drive end bearing are ceramic balls and the cage is made of insulating material; an insulating coating is provided between the outer wall of the inner ring of the non-drive end bearing and the rolling elements; and an insulating coating is provided between the inner wall of the outer ring of the non-drive end bearing and the rolling elements.

[0016] In one embodiment, the insulating structure between the non-drive end bearing and the motor shaft includes any one or more of the following: an insulating coating is provided on the area of ​​the motor shaft that contacts the inner ring of the non-drive end bearing; an insulating sleeve is fitted on the area of ​​the motor shaft that contacts the inner ring of the non-drive end bearing; and an insulating coating is provided on the inner wall of the inner ring of the non-drive end bearing.

[0017] In one embodiment, the electric drive assembly further includes conductive elements;

[0018] One end of the conductive component is electrically connected to the motor shaft, and the other end of the conductive component is electrically connected to the housing.

[0019] In one embodiment, the conductive element is any one of a conductive ring, a conductive carbon brush, a conductive brush, or a conductive spring.

[0020] In one embodiment, a drive end bearing is fitted onto the end of the motor shaft closest to the reducer shaft, an input end bearing is fitted onto the end of the reducer shaft closest to the motor shaft, and an output end bearing is fitted onto the end of the reducer shaft furthest from the motor shaft.

[0021] In one embodiment, the diameter of the motor shaft is greater than the diameter of the output half-shaft and greater than the diameter of the reducer shaft.

[0022] In one embodiment, the motor further includes a rotor, a stator core, and stator windings;

[0023] The rotor is mounted on the motor shaft, and the stator core is located around the rotor and arranged coaxially with the rotor. The stator winding is wound on the stator core.

[0024] In one embodiment, the electric drive assembly further includes a motor controller;

[0025] The motor controller is connected to the stator winding and outputs a pulse width modulation signal to control the motor.

[0026] In one embodiment, the planetary gear reducer further includes a sun gear sleeved on the reducer shaft, a plurality of planet gears meshing with the sun gear, and a gear ring meshing with at least one planet gear;

[0027] The gear ring is electrically connected to the housing.

[0028] In one embodiment, the planetary gear reducer further includes a planet carrier connected to the motor shaft and the reducer shaft respectively, and the planet carrier is provided with a plurality of planet gear shafts;

[0029] Multiple planetary gears include multiple first-level planetary gears and multiple second-level planetary gears;

[0030] The number of planetary gear shafts, primary planetary gears, and secondary planetary gears is the same, and the primary planetary gears and secondary planetary gears are fitted one-to-one on each planetary gear shaft. Each primary planetary gear meshes with the sun gear, and each secondary planetary gear meshes with the ring gear.

[0031] To achieve the above objectives, this application also proposes an electric vehicle, including a battery and an electric drive assembly as described above, wherein the battery is used to provide electrical energy to the electric drive assembly.

[0032] One or more technical solutions proposed in this application have at least the following technical effects:

[0033] An electric drive assembly is proposed, comprising a housing, a motor, and a planetary gear reducer. The motor shaft and the reducer shaft of the planetary gear reducer are coaxially connected. An output half-shaft is also coaxially connected to the end of the motor shaft away from the reducer shaft. The output half-shaft is fitted with a half-shaft bearing, and a non-drive end bearing is fitted to the end of the motor shaft near the output half-shaft. For this coaxial planetary gear electric drive assembly with multiple bearings, multiple different circulating shaft current loops will be formed between the multiple bearings and the gears. Therefore, by insulating the half-shaft bearings from the housing and the non-drive end bearings from the housing, the circulating shaft currents in the loops can be blocked. This insulates both the half-shaft bearings and the non-drive end bearings from the housing, protecting the half-shaft bearings and the non-drive end bearings while also suppressing corrosion problems in other components of the electric drive assembly, such as other bearings or other components within the reducer. Attached Figure Description

[0034] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0035] To more clearly illustrate the technical solutions in the embodiments or related technologies of this application, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0036] Figure 1 This is a schematic diagram of the structure of a parallel-axis electric drive assembly in the related technology;

[0037] Figure 2 A schematic diagram of a coaxial planetary electric drive assembly provided in an embodiment of this application;

[0038] Figure 3 for Figure 2 A schematic diagram of the equivalent circuit of the common mode shaft voltage in the coaxial planetary electric drive assembly;

[0039] Figure 4 for Figure 2 A schematic diagram of the equivalent circuit of the circulating shaft current loop in the coaxial planetary electric drive assembly.

[0040] Figure 5 A pair of proportional structural schematic diagrams of a coaxial planetary electric drive assembly provided in an embodiment of this application;

[0041] Figure 6 This is another structural schematic diagram of a coaxial planetary electric drive assembly provided in an embodiment of this application;

[0042] Figure 7This is a schematic diagram of the structure of a coaxial planetary electric drive assembly provided in another embodiment of this application.

[0043] Explanation of icon numbers:

[0044] 100. Housing; 110. Motor cavity; 111. Motor shaft; 112. Non-drive end bearing; 113. Drive end bearing; 114. Rotor; 115. Stator core; 116. Stator winding; 120. Reducer cavity; 121. Reducer shaft; 122. Input end bearing; 123. Output end bearing; 124. Sun gear; 125. Planet gears; 1251. First-stage planetary gear; 1252. Second-stage planetary gear; 126. Gear ring; 127. Planet carrier; 128. Planetary gear shaft; 130. Output cavity; 131. Output half-shaft; 132. Half-shaft bearing; 140. Insulating component; 150. Conductive component.

[0045] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0046] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0047] It should be noted that if the embodiments of this application involve directional indications (such as up, down, left, right, front, back, etc.), these directional indications are only used to explain the relative positional relationships and movement of the components in a specific posture. If the specific posture changes, the directional indications will also change accordingly. Furthermore, if the embodiments of this application involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" can explicitly or implicitly include at least one of those features. Additionally, if "and / or" or "and / or" appears throughout the text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or a solution where A and B are simultaneously satisfied. Furthermore, the technical solutions of the various embodiments can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0048] Currently, in the drive motors or electric drive assemblies of new energy vehicles, during operation, the pulse width modulation (PWM) signal output by the motor controller generates a common-mode voltage between the three-phase windings of the motor and the housing. Due to the voltage division effect of parasitic capacitance on the drive motor or electric drive assembly, a bearing voltage is formed between the inner and outer rings of the bearing. When the bearing voltage exceeds the oil film breakdown voltage, a discharge phenomenon occurs between the inner and outer rings of the bearing, generating an EDM (Electrical Discharge Machining) discharge current, which causes electro-corrosion damage to the bearing and endangers the stable operation of the motor. The ratio of the bearing voltage to the common-mode voltage is called the voltage division ratio. In related technologies, a conductive element is generally used to short-circuit the shaft and the housing to reduce the voltage division ratio, thereby eliminating the influence of the current corresponding to the common-mode shaft voltage on the bearing.

[0049] On the other hand, in drive motors, the high dv / dt (voltage change rate) at the motor ends and the parasitic capacitance of the stator windings to the housing together induce high-frequency common-mode currents. These common-mode currents generate a toroidal common-mode magnetic flux within the motor's stator core, which induces a cyclic shaft current in the closed loop of "housing-non-drive end bearing-shaft-drive end bearing." In related technologies, insulating elements are typically used to increase the impedance of the cyclic shaft current loop, thereby eliminating the influence of the cyclic shaft current on the bearings.

[0050] In electric drive assemblies, due to the presence of the reducer, the drive end typically has multiple bearings, resulting in multiple different circulating shaft current loops. Different electric drive assembly configurations lead to significant differences in these circulating shaft current loops. Therefore, for different electric drive assemblies, it is necessary to consider the configuration differences and design corresponding bearing electro-corrosion suppression schemes, especially the specific design of schemes to improve the impedance of the circulating shaft current loop is crucial.

[0051] Improper use of conductive components to suppress common-mode shaft current can reduce the impedance of the circulating shaft current loop, increasing the damage caused by the circulating shaft current to the bearing. Conversely, improper use of insulating components to suppress circulating shaft current can increase the voltage division ratio, leading to an increase in the common-mode shaft voltage and further increasing the damage caused by the common-mode shaft current to the bearing. Therefore, inappropriate electro-corrosion suppression measures can actually increase the risk of electro-corrosion in the bearings of the electric drive assembly.

[0052] Therefore, designing bearing electro-corrosion suppression schemes according to the configuration differences of different electric drive assemblies, so as to avoid the damage of common-mode shaft current and cyclic shaft current to multiple bearings of the electric drive assembly, is an urgent technical problem to be solved.

[0053] To address the aforementioned problems, this application provides an electric drive assembly and an electric vehicle. The application and its embodiments will be described below with reference to the accompanying drawings.

[0054] This application proposes an electric drive assembly.

[0055] In related technologies, electric drive assemblies include parallel-axis electric drive assemblies and coaxial planetary gear electric drive assemblies.

[0056] Currently, in some parallel-axis electric drive assemblies, the bearings on the non-drive end of the motor are made insulated, and conductive elements are installed on the drive end of the motor to short-circuit the shaft to the housing, in order to solve the electro-corrosion hazards of cyclic shaft current and common-mode shaft current on the bearings. For example... Figure 1 The diagram shows a schematic of a parallel-axis electric drive assembly in the related art, including a motor 01 and a reducer 02. The motor 01 includes a housing 011, a rotating shaft 012 located inside the housing 011, and non-driving end bearings 013 and driving end bearings 014 wound around both ends of the rotating shaft 012. The reducer 02 includes a reducer housing 021, multiple gear shafts 022 located inside the reducer housing 021 and arranged in parallel, multiple gears 023 respectively mounted on each gear shaft 022, and bearings 024 wound around both ends of each gear shaft 022. The bearing 024 at the end of the gear shaft 022 coaxial with the rotating shaft 012 closest to the motor 01 is the driving end bearing 014 of the motor 01. In the reducer 02, the multiple gears 023 mesh with each other in pairs, and there is a gap between the outermost gear 023 and the reducer housing 021, that is, the gears 023 and the reducer housing 021 do not contact or connect.

[0057] like Figure 1 In the parallel-axis electric drive assembly shown, an insulating element 03 is sleeved on the outer wall of the non-drive end bearing 013, which insulates the non-drive end bearing 013 of the motor of the parallel-axis electric drive assembly from the housing 011. This can block the circulating shaft current in all circulating shaft current loops and prevent all bearings from being affected by the circulating shaft current. A conductive element 04 is connected between the rotating shaft 012 and the housing 011, which makes the motor drive end of the parallel-axis electric drive assembly conductive and can suppress the common-mode shaft current affecting all bearings.

[0058] In one embodiment of the electric drive assembly of this application, the electric drive assembly is a coaxial planetary gear electric drive assembly, as shown in the reference. Figure 2 , Figure 2 This is a schematic diagram of a coaxial planetary gearbox electric drive assembly provided in this embodiment. The coaxial planetary gearbox electric drive assembly may include a housing 100 and a motor and a planetary gearbox reducer disposed within the housing 100; the motor includes a motor shaft 111, the planetary gearbox reducer includes a reducer shaft 121, the motor shaft 111 and the reducer shaft 121 are coaxially connected, and the end of the motor shaft 111 away from the reducer shaft 121 is also coaxially connected to an output half shaft 131.

[0059] For example, housing 100 can be divided into motor housing, reducer housing, and output housing; or, as Figure 2 As shown, the internal cavity of the housing 100 can be divided into a motor cavity 110, a reducer cavity 120 and an output cavity 130. The motor shaft 111 is located in the motor cavity 110, the reducer shaft 121 is located in the reducer cavity 120, and the output half shaft 131 is located in the output cavity 130.

[0060] In this embodiment, we continue to refer to... Figure 2 A half-shaft bearing 132 is fitted at the end of the output half-shaft 131 away from the motor shaft 111, and a non-drive end bearing 112 is fitted at the end of the motor shaft 111 near the output half-shaft 131.

[0061] In one alternative implementation, refer to Figure 2 A drive end bearing 113 is fitted onto the end of the motor shaft 111 closest to the reducer shaft 121, an input end bearing 122 is fitted onto the end of the reducer shaft 121 closest to the motor shaft 111, and an output end bearing 123 is fitted onto the end of the reducer shaft 121 furthest from the motor shaft 111.

[0062] It should be noted that in practical applications, the drive end bearing 113 and the input end bearing 122 can be combined into one bearing or set independently; no specific limitation is made here. Figure 2 The diagram shown is merely one example of the coaxial planetary electric drive assembly provided in this embodiment.

[0063] In one optional embodiment, the diameter of the motor shaft 111 is greater than the diameter of the output half-shaft 131 and greater than the diameter of the reducer shaft 121.

[0064] It is understandable that the motor shaft needs to directly bear the peak electromagnetic torque, and increasing the shaft diameter can improve the section coefficient and optimize the torque bearing performance.

[0065] In one optional embodiment, the motor further includes a rotor 114, a stator core 115, and a stator winding 116; the rotor 114 is sleeved on the motor shaft 111, the stator core 115 is disposed around the rotor 114 and arranged coaxially with the rotor 114, and the stator winding 116 is wound on the stator core 115.

[0066] In one alternative embodiment, the electric drive assembly may further include a motor controller 200; the motor controller 200 is connected to the stator winding 116 and outputs a pulse width modulation (PWM) signal to achieve motor control. The motor controller 200 may be an inverter.

[0067] In one alternative implementation, refer to Figure 2The planetary gear reducer may also include a sun gear 124 sleeved on the reducer shaft 121, a plurality of planet gears 125 meshing with the sun gear 124, and a gear ring 126 meshing with at least one planet gear 125, the gear ring 126 being electrically connected to the housing 100.

[0068] like Figure 2 As shown, in this coaxial planetary electric drive assembly, parasitic capacitances include the coupling capacitance Crf between the stator core 115 and the rotor 114, the coupling capacitance Cwf between the stator core 115 and the stator winding 116, and the coupling capacitance Cwr between the stator winding 116 and the rotor 114; there is a coupling capacitance Crr between the motor shaft 111 and the output half-shaft 131; the half-shaft bearing 132 is equivalent to a parallel resistor Rb1 and a capacitor Cb1, and the non-drive end bearing 112, etc. The driving end bearing 113 is equivalent to a parallel resistor Rb2 and capacitor Cb2, the input end bearing 122 is equivalent to a parallel resistor Rb4 and capacitor Cb4, and the output end bearing 123 is equivalent to a parallel resistor Rb5 and capacitor Cb5; the meshing of the sun gear 124 and planet gear 125 is equivalent to a parallel resistor Rg1 and capacitor Cg1, and the meshing of the planet gear 125 and the gear ring 126 is equivalent to a parallel resistor Rg2 and capacitor Cg2.

[0069] Based on the above definition, we can obtain the following: Figure 3 The diagram shows the equivalent circuit diagram of the common mode shaft voltage in the coaxial planetary gear electric drive assembly, and as shown below... Figure 4 The diagram shows the equivalent circuit of the circulating shaft current loop in the coaxial planetary gear electric drive assembly.

[0070] like Figure 3 As shown, the PWM signal output by the motor controller 200 generates a common-mode voltage Vcom between the three-phase windings a, b, and c of the motor and the housing 100. Due to the voltage division effect of the parasitic capacitors (Cwf, Cwr, Crf), a common-mode shaft voltage Vb1 is formed. Due to the voltage division effect of the coupling capacitor Crr, a common-mode shaft voltage Vb2 is further formed.

[0071] like Figure 4 As shown, Icom represents the total current input to the electric drive assembly. Under the influence of parasitic capacitances (Cwf, Cwr, Crf), after Ig is shunt through the corresponding equivalent impedances Rg and Lg, the common-mode current Ib is obtained; as shown... Figure 2 and Figure 4As shown, the common-mode current Ib generates a ring-shaped common-mode magnetic flux within the motor. This magnetic flux induces a cyclic shaft current Ib1 in multiple closed loops of the coaxial planetary gearbox electric drive assembly, based on the equivalent impedances Rr1 and Lr1 of the output half-shaft 131, the motor shaft 111, and the reducer shaft 121, as well as the equivalent impedances Rf and Lf of the housing 100. Furthermore, a cyclic shaft current Ib2 is induced based on the equivalent impedances Rr2 and Lr2 of the motor shaft 111 and the equivalent impedances Rf and Lf of the housing 100. In other words, multiple cyclic shaft current loops are formed in the coaxial planetary gearbox electric drive assembly.

[0072] To eliminate the effects of common-mode shaft current and cyclic shaft current on bearings, the aforementioned electro-corrosion suppression measures (i.e., setting the bearing at the non-drive end of the motor to be insulated and installing a conductive element at the drive end of the motor to short-circuit the shaft to the housing) were tentatively applied to applications such as... Figure 2 In the coaxial planetary electric drive assembly shown, the following will be obtained: Figure 5 The diagram shows a pair of proportional structural schematics of the coaxial planetary electric drive assembly.

[0073] exist Figure 5 In this example, an insulating element 03 is fitted on the outer wall of the non-drive end bearing 112 to insulate the non-drive end bearing 112 from the housing 100. A conductive element 04 connects the motor shaft 111 to the housing 100. It can be seen that in this comparative example of a coaxial planetary gear electric drive assembly, although it can protect the bearings at both ends of the motor, it does not protect the half-shaft bearing 132 on the output half-shaft 131. Moreover, the circulating shaft current Ib2 conducted on the output half-shaft 131 will cause electro-corrosion of the bearings at both ends of the reducer shaft 121.

[0074] This analysis reveals that, due to the characteristics of the coaxial planetary electric drive assembly, the bearing architecture is more complex, containing multiple bearings, such as... Figure 2 The diagram shows five bearings, so it's necessary to distinguish between the motor shaft, reducer shaft, and output half-shaft, as well as the corresponding bearing supports. Therefore, separate shaft current suppression schemes need to be considered. The shaft current suppression schemes currently used in parallel shaft electric drive assemblies are not suitable for this coaxial planetary gearbox electric drive assembly because they cannot effectively solve the damage caused by cyclic shaft currents Ib1 and Ib2 to all bearings. This means the coaxial planetary gearbox electric drive assembly cannot effectively prevent all bearings from being affected by cyclic shaft currents. Furthermore, due to the large diameter of the motor shaft 111, the reliability of the conductive element 04 is insufficient; the conductive element is prone to wear and has a short lifespan, which may cause other problems for the coaxial planetary gearbox electric drive assembly.

[0075] In fact, Figure 2In the coaxial planetary gear electric drive assembly, capacitors Cg1 and Cg2 are in a low-resistance state, and the common-mode shaft voltage Vb1 tends to 0. Even without conductive elements, the gear ring 126 is electrically connected to the housing 100, which allows for... Figure 3 The equivalent circuit of the common-mode shaft voltage shown is grounded, which reduces the ratio of bearing voltage Vb1 to common-mode voltage Vcom and the ratio of bearing voltage Vb2 to common-mode voltage Vcom, so that the current corresponding to the common-mode shaft voltage will not affect all bearings.

[0076] The electric drive assembly provided in this embodiment can suppress the influence of common mode shaft current on the bearing by electrically connecting the gear ring to the housing. Compared with the parallel shaft electric drive assembly, the coaxial planetary gear electric drive assembly does not require additional conductive components, which saves costs and avoids other effects caused by the easy wear and short life of conductive components.

[0077] Furthermore, after eliminating the influence of common-mode shaft current on the bearing, it is also necessary to eliminate the influence of cyclic shaft current on the bearing for the multiple cyclic shaft current loops formed in the coaxial planetary gear electric drive assembly.

[0078] Depend on Figure 4 It can be observed that Cg1 and Cg2 in the reducer are connected, which means that the coaxial planetary gear electric drive system becomes a large circulating loop. By blocking Ib1 and Ib2 at the source, the bearing electro-corrosion can be effectively suppressed.

[0079] Reference Figure 6 , Figure 6 The diagram shown is another structural schematic of the coaxial planetary gear electric drive assembly provided in this embodiment. In this coaxial planetary gear electric drive assembly, the half-shaft bearing 132 is insulated from the housing 100, and the non-drive end bearing 112 is insulated from the housing 100.

[0080] The electric drive assembly provided in this embodiment, by insulating both the half-shaft bearing and the housing, as well as the non-drive end bearing and the housing, can block the cyclic shaft current in all circulating shaft current loops. This protects the half-shaft bearing and the non-drive end bearing, while also suppressing corrosion problems in other components of the electric drive assembly, such as other bearings or other components in the reducer. This ensures that all bearings are not affected by the cyclic shaft current, thus preventing both the harm of common-mode shaft current and the harm of cyclic shaft current from all bearings in the coaxial planetary gear electric drive assembly.

[0081] In one feasible embodiment, the half-shaft bearing 132 is insulated from the housing 100, and the non-drive end bearing 112 is insulated from the housing 100. This may include:

[0082] An insulating structure is provided between the half-shaft bearing 132 and the housing 100, the half-shaft bearing 132 is an insulated bearing, and / or an insulating structure is provided between the half-shaft bearing 132 and the output half-shaft 131; and an insulating structure is provided between the non-drive end bearing 112 and the housing 100, the non-drive end bearing 112 is an insulated bearing, and / or an insulating structure is provided between the non-drive end bearing 112 and the motor shaft 111.

[0083] In this embodiment, the five bearings, namely the half-shaft bearing 132, the non-drive end bearing 112, the drive end bearing 113, the input end bearing 122, and the output end bearing 123, can adopt similar or identical bearing structures. The bearing structure can include an inner ring, a first oil film formed by lubricating oil, rolling elements, a second oil film formed by lubricating oil, and an outer ring arranged sequentially from the inside to the outside. It can also include a cage, which can position and isolate multiple rolling elements and constrain the circumferential movement of the rolling elements.

[0084] In specific applications, the insulation method used between the half-shaft bearing 132 and the housing 100 can be the same as or different from the insulation method used between the non-drive end bearing 112 and the housing 100. For example, if the same insulation method is used, both the half-shaft bearing 132 and the non-drive end bearing 112 can be insulated bearings, such as using ceramic balls for the rolling elements and insulated cages for both. Alternatively, insulation structures can be provided between the half-shaft bearing 132 and the housing 100, and between the non-drive end bearing 112 and the housing 100, such as wrapping insulating elements 140 around the outer walls of both the outer rings of the half-shaft bearing 132 and the non-drive end bearing 112. If different insulation methods are used, an insulation structure can be provided between the half-shaft bearing 132 and the housing 100, and the non-drive end bearing 112 can be an insulated bearing; or the half-shaft bearing 132 can be an insulated bearing, and an insulation structure can be provided between the non-drive end bearing 112 and the motor shaft 111, etc. In practical applications, the specific insulation method mentioned above can be selected as needed to ensure that the half-shaft bearing 132 is insulated from the housing 100 and the non-drive end bearing 112 is insulated from the housing 100. No specific limitation is made here.

[0085] In practical applications, multiple insulation methods can be used in combination to achieve better insulation effects. For example, if an insulation structure is provided between the half-shaft bearing 132 and the housing 100 and the half-shaft bearing 132 is an insulated bearing, an insulation structure can be provided between the non-drive end bearing 112 and the housing 100; it is even possible to further make the non-drive end bearing 112 an insulated bearing.

[0086] In one optional embodiment, the insulating structure between the half-shaft bearing 132 and the housing 100 may include any one or more of the following: providing an insulating coating on the outer wall of the outer ring of the half-shaft bearing 132, wrapping an insulating member 140 around the outer wall of the outer ring of the half-shaft bearing 132, and providing an insulating coating on the area of ​​the housing 100 that contacts the half-shaft bearing 132.

[0087] It should be noted that the specific method of setting the insulating coating on the outer wall of the outer ring of the half-shaft bearing 132 and the specific method of setting the insulating coating on the area of ​​the housing 100 that contacts the half-shaft bearing 132 can both insulate the bearing from the housing; the specific method of wrapping the outer wall of the outer ring of the half-shaft bearing 132 with the insulating element 140 can completely isolate the bearing from the housing and achieve insulation between the bearing and the housing.

[0088] In one optional embodiment, the use of an insulated bearing for the half-shaft bearing 132 may include any one or more of the following: the rolling elements of the half-shaft bearing 132 are ceramic balls and the cage is made of insulating material; an insulating coating is provided between the outer wall of the inner ring of the half-shaft bearing 132 and the rolling elements; and an insulating coating is provided between the inner wall of the outer ring of the half-shaft bearing 132 and the rolling elements.

[0089] It should be noted that in the specific method of using ceramic balls for the rolling elements and insulating material for the cage of the half-shaft bearing 132, the ceramic balls can specifically be silicon nitride ceramic balls, and the cage can specifically be a high-speed nylon cage. In this case, the inner and outer rings of the bearing are still steel rings. The ceramic balls have significant insulating properties, and the nylon cage also has an insulating effect. The insulating bearing formed by the two can effectively block the circulating shaft current loop and insulate the bearing from the housing. The insulating bearing formed by setting an insulating coating between the outer wall of the inner ring of the half-shaft bearing 132 and the rolling elements, and the insulating coating between the inner wall of the outer ring of the half-shaft bearing 132 and the rolling elements, can achieve insulation between the output half-shaft 131 inside the half-shaft bearing 132 and the housing 100 outside the half-shaft bearing 132 after insulating the inner and outer rings of the bearing, thereby cutting off the circulating shaft current loop.

[0090] In one optional embodiment, the insulating structure between the half-shaft bearing 132 and the output half-shaft 131 may include any one or more of the following: an insulating coating is provided on the area of ​​the output half-shaft 131 that contacts the inner ring of the half-shaft bearing 132; an insulating sleeve is fitted on the area of ​​the output half-shaft 131 that contacts the inner ring of the half-shaft bearing 132; and an insulating coating is provided on the inner wall of the inner ring of the half-shaft bearing 132.

[0091] It should be noted that the specific method of setting an insulating coating on the area of ​​the output half-shaft 131 that contacts the inner ring of the half-shaft bearing 132, and the specific method of setting an insulating coating on the inner wall of the inner ring of the half-shaft bearing 132, can both insulate the shaft from the bearing, thereby achieving complete insulation between the shaft and the housing; the specific method of sleeved insulating sleeve on the area of ​​the output half-shaft 131 that contacts the inner ring of the half-shaft bearing 132 can completely isolate the shaft from the bearing, achieving insulation between the half-shaft bearing 132 and the output half-shaft 131, thereby cutting off the circulating shaft current circuit.

[0092] In one optional embodiment, the insulating structure between the non-drive end bearing 112 and the housing 100 may include any one or more of the following: providing an insulating coating on the outer wall of the outer ring of the non-drive end bearing 112, wrapping an insulating member 140 around the outer wall of the outer ring of the non-drive end bearing 112, and providing an insulating coating on the area of ​​the housing 100 that contacts the non-drive end bearing 112.

[0093] It should be noted that the specific method of setting the insulating coating on the outer wall of the outer ring of the non-drive end bearing 112 and the specific method of setting the insulating coating on the area of ​​the housing 100 that contacts the non-drive end bearing 112 can both insulate the bearing from the housing; the specific method of wrapping the outer wall of the outer ring of the non-drive end bearing 112 with the insulating member 140 can completely isolate the bearing from the housing and achieve insulation between the bearing and the housing.

[0094] In one optional embodiment, the non-drive end bearing 112 adopting an insulated bearing may include any one or more of the following: the rolling elements of the non-drive end bearing 112 are ceramic balls and the cage is made of insulating material; an insulating coating is provided between the outer wall of the inner ring of the non-drive end bearing 112 and the rolling elements; and an insulating coating is provided between the inner wall of the outer ring of the non-drive end bearing 112 and the rolling elements.

[0095] It should be noted that in the specific method of using ceramic balls for the rolling elements and insulating material for the cage of the non-drive end bearing 112, the ceramic balls can specifically be silicon nitride ceramic balls, and the cage can specifically be a high-speed nylon cage. In this case, the inner and outer rings of the bearing are still steel rings. The ceramic balls have significant insulating properties, and the nylon cage also has an insulating effect. The insulating bearing formed by the two can effectively block the circulating shaft current loop and insulate the bearing from the housing. The insulating bearing formed by the specific method of setting an insulating coating between the outer wall of the inner ring of the non-drive end bearing 112 and the rolling elements, and the specific method of setting an insulating coating between the inner wall of the outer ring of the non-drive end bearing 112 and the rolling elements, after insulating the inner and outer rings of the bearing, can achieve insulation between the motor shaft 111 inside the non-drive end bearing 112 and the housing 100 outside the non-drive end bearing 112, thereby cutting off the circulating shaft current loop.

[0096] In one optional embodiment, the insulating structure between the non-drive end bearing 112 and the motor shaft 111 may include any one or more of the following: providing an insulating coating on the area of ​​the motor shaft 111 that contacts the inner ring of the non-drive end bearing 112; covering the area of ​​the motor shaft 111 that contacts the inner ring of the non-drive end bearing 112 with an insulating sleeve; and providing an insulating coating on the inner wall of the inner ring of the non-drive end bearing 112.

[0097] It should be noted that the specific method of setting an insulating coating on the area of ​​the motor shaft 111 in contact with the inner ring of the non-drive end bearing 112, and the specific method of setting an insulating coating on the inner wall of the inner ring of the non-drive end bearing 112, can both insulate the shaft from the bearing, thereby achieving complete insulation between the shaft and the housing; the specific method of covering the area of ​​the motor shaft 111 in contact with the inner ring of the non-drive end bearing 112 with an insulating sleeve can completely isolate the shaft from the bearing, achieving insulation between the non-drive end bearing 112 and the motor shaft 111, thereby cutting off the circulating shaft current circuit.

[0098] It should also be noted that more specific implementation methods can be selected from any one or more of the above specific methods as needed, or multiple specific methods can be used in combination as needed to achieve better insulation effect. Specifically, after considering factors such as force and arrangement position, the insulation between the half-shaft bearing and the housing and the insulation between the non-drive end bearing and the housing can be configured with the same insulation method or different insulation methods, which will not be elaborated here.

[0099] For example, such as Figure 6 As shown, the inner ring of the half-shaft bearing 132 is connected to and sleeved on the output half-shaft 131. The outer wall of the outer ring of the half-shaft bearing 132 is wrapped with an insulating member 140, which connects it to the housing 100. The inner rings of the non-drive end bearing 112 and the drive end bearing 113 are both connected to the motor shaft 111 and sleeved on both ends of the motor shaft 111. The outer wall of the outer ring of the non-drive end bearing 112 is wrapped with an insulating member 140, which connects it to the housing 100. The outer ring of the drive end bearing 113 is directly connected to the housing 100. The inner rings of the input end bearing 122 and the output end bearing 123 are both connected to the reducer shaft 121 and sleeved on both ends of the reducer shaft 121. The outer rings of the input end bearing 122 and the output end bearing 123 are directly connected to the housing 100.

[0100] Optionally, the insulating element 140 can be a ring structure made of insulating materials such as polyetheretherketone (PEEK) rings or polyphenylene sulfide (PPS) rings.

[0101] Understandably, polyetheretherketone (PEEK) is a high-performance engineering plastic. Due to its excellent mechanical properties, such as high strength, high rigidity, and wear resistance, it can withstand the mechanical stress and wear generated during the operation of the electric drive assembly, ensuring its stable operation. Simultaneously, its high dielectric strength allows it to maintain good insulation performance under high voltage. Polyphenylene sulfide (PPS) is a high-performance thermoplastic engineering plastic with excellent high-temperature resistance, chemical corrosion resistance, flame retardancy, and mechanical strength. Using PEEK or PPS rings to encase bearings can effectively block the flow of multiple cyclic shaft currents in their respective loops, thereby effectively preventing cyclic shaft currents from damaging all bearings of the coaxial planetary electric drive assembly.

[0102] This embodiment provides a coaxial planetary gearbox electric drive assembly with multiple bearings. In the planetary gearbox reducer, the common-mode shaft current can be suppressed by electrically connecting the gear ring to the housing, eliminating the need for additional conductive components and saving costs. However, multiple bearings and gears will form multiple different circulating shaft current loops. Therefore, by setting an insulating structure between the half-shaft bearing and the housing, as well as between the non-drive end bearing and the housing, the circulating shaft current can be blocked, making both the half-shaft bearing and the non-drive end bearing insulated from the housing. This protects the half-shaft bearing and the non-drive end bearing while also suppressing corrosion problems in other components of the electric drive assembly, such as other bearings or other components in the reducer (such as splines).

[0103] In another embodiment of the electric drive assembly of this application, reference is made to Figure 7 , Figure 7 This is a schematic diagram of the coaxial planetary gear electric drive assembly provided in this embodiment. The electric drive assembly may also include a conductive element 150; one end of the conductive element 150 is electrically connected to the motor shaft 111, and the other end of the conductive element 150 is electrically connected to the housing 100.

[0104] It should be noted that although the addition of conductive component 150 is useless for suppressing bearing electro-corrosion, it is possible that in some specific cases, conductive component 150 may be added in order to improve the EMC (Electromagnetic Compatibility) performance of the motor.

[0105] In one feasible implementation, the conductive element 150 can be any one of a conductive ring, a conductive carbon brush, a conductive brush, or a conductive spring.

[0106] The conductive component 150 is made of conductive material, and its specific structure can be selected from any one of the following, such as a conductive ring, conductive carbon brush, conductive brush, or conductive spring sheet, depending on actual needs.

[0107] Understandably, grounding the motor shaft via conductive components prevents high-frequency shaft voltage from being conducted to the output half-shaft, thus avoiding the antenna effect of the output half-shaft from affecting EMC performance. Furthermore, the conductive components can be adapted to various specific motor structures, allowing the electric drive assembly to meet the needs of more operating environments and exhibiting good adaptability.

[0108] In one feasible implementation, such as Figure 7 As shown, the planetary gear reducer may also include a planet carrier 127 that is connected to the motor shaft 111 and the reducer shaft 121 respectively, and a plurality of planet gear shafts 128 are provided on the planet carrier 127;

[0109] The multiple planetary gears 125 include multiple first-stage planetary gears 1251 and multiple second-stage planetary gears 1252; the number of multiple planetary gear shafts 128, multiple first-stage planetary gears 1251 and multiple second-stage planetary gears 1252 is the same, and the multiple first-stage planetary gears 1251 and multiple second-stage planetary gears 1252 are fitted one-to-one on each planetary gear shaft 128. Each first-stage planetary gear 1251 meshes with the sun gear 124, and each second-stage planetary gear 1252 meshes with the gear ring 126.

[0110] In this embodiment, the gear ring is still electrically connected to the housing, so the influence of common-mode shaft current on the bearing can still be suppressed. It is still only necessary to set the half-shaft bearing and the non-drive end bearing as an insulating structure to make the half-shaft bearing and the housing, as well as the non-drive end bearing and the housing, to block the cyclic shaft current of all circulating shaft current loops, so that all bearings are not affected by the cyclic shaft current.

[0111] The electric drive assembly provided in this embodiment can improve EMC performance while ensuring that all bearings can avoid the hazards of both common-mode shaft current and cyclic shaft current.

[0112] This application also proposes an electric vehicle.

[0113] In one embodiment of the electric vehicle, the electric vehicle may include a battery and an electric drive assembly as described in the above embodiments; the battery is used to provide electrical energy to the electric drive assembly.

[0114] It should be noted that the specific structure of the electric drive assembly can be referred to the above embodiments. Since the electric vehicle adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be repeated here.

[0115] The above are only some embodiments of this application and do not limit the scope of protection of this application. All equivalent structural transformations made under the technical concept of this application and using the content of this application specification and drawings, or direct / indirect applications in other related technical fields, are included in the scope of protection of this application.

Claims

1. An electric drive assembly, characterized by The electric drive assembly is a coaxial planetary gear electric drive assembly, which includes a housing and a motor and a planetary gear reducer disposed within the housing; The motor includes a motor shaft, the planetary gear reducer includes a reducer shaft, the motor shaft is coaxially connected to the reducer shaft, and an output half shaft is coaxially connected to the end of the motor shaft away from the reducer shaft. A half shaft bearing is sleeved on the end of the output half shaft away from the motor shaft, and a non-drive end bearing is sleeved on the end of the motor shaft close to the output half shaft. The half-shaft bearing is insulated from the housing, and the non-drive end bearing is insulated from the housing.

2. The electric drive assembly of claim 1, wherein, The half-shaft bearing is insulated from the housing, and the non-drive end bearing is insulated from the housing, including: An insulating structure is provided between the half-shaft bearing and the housing; the half-shaft bearing is an insulated bearing; and / or an insulating structure is provided between the half-shaft bearing and the output half-shaft; and... An insulating structure is provided between the non-driving end bearing and the housing, the non-driving end bearing is an insulated bearing, and / or an insulating structure is provided between the non-driving end bearing and the motor shaft.

3. The electric drive assembly of claim 2, wherein, The insulating structure between the half-shaft bearing and the housing includes any one or more of the following: providing an insulating coating on the outer wall of the outer ring of the half-shaft bearing, wrapping an insulating element around the outer wall of the outer ring of the half-shaft bearing, and providing an insulating coating on the area of ​​the housing that contacts the half-shaft bearing.

4. The electric drive assembly of claim 2, wherein, The half-shaft bearing is an insulated bearing, including any one or more of the following: the rolling elements of the half-shaft bearing are ceramic balls and the cage is made of insulating material; an insulating coating is provided between the outer wall of the inner ring of the half-shaft bearing and the rolling elements; and an insulating coating is provided between the inner wall of the outer ring of the half-shaft bearing and the rolling elements.

5. The electric drive assembly of claim 2, wherein, The insulating structure provided between the half-shaft bearing and the output half-shaft includes any one or more of the following: an insulating coating is provided on the area of ​​the output half-shaft that contacts the inner ring of the half-shaft bearing; an insulating sleeve is fitted on the area of ​​the output half-shaft that contacts the inner ring of the half-shaft bearing; and an insulating coating is provided on the inner wall of the inner ring of the half-shaft bearing.

6. The electric drive assembly of claim 2, wherein, The insulating structure between the non-driving end bearing and the housing includes any one or more of the following: providing an insulating coating on the outer wall of the outer ring of the non-driving end bearing, wrapping an insulating element around the outer wall of the outer ring of the non-driving end bearing, and providing an insulating coating on the area of ​​the housing that contacts the non-driving end bearing.

7. The electric drive assembly of claim 2, wherein, The non-drive end bearing is an insulated bearing, including any one or more of the following: the rolling elements of the non-drive end bearing are ceramic balls and the cage is made of insulating material; an insulating coating is provided between the outer wall of the inner ring of the non-drive end bearing and the rolling elements; and an insulating coating is provided between the inner wall of the outer ring of the non-drive end bearing and the rolling elements.

8. The electric drive assembly of claim 2, wherein, The insulating structure between the non-driving end bearing and the motor shaft includes any one or more of the following: an insulating coating is provided on the area of ​​the motor shaft that contacts the inner ring of the non-driving end bearing; an insulating sleeve is fitted on the area of ​​the motor shaft that contacts the inner ring of the non-driving end bearing; and an insulating coating is provided on the inner wall of the inner ring of the non-driving end bearing.

9. The electric drive assembly of claim 1, wherein, The electric drive assembly also includes conductive components; One end of the conductive element is electrically connected to the motor shaft, and the other end of the conductive element is electrically connected to the housing.

10. The electric drive assembly of claim 9, wherein, The conductive component is any one of a conductive ring, a conductive carbon brush, a conductive brush, or a conductive spring.

11. The electric drive assembly of claim 1, wherein, A drive end bearing is fitted onto the end of the motor shaft closest to the reducer shaft, an input end bearing is fitted onto the end of the reducer shaft closest to the motor shaft, and an output end bearing is fitted onto the end of the reducer shaft furthest from the motor shaft.

12. The electric drive assembly of claim 1, wherein, The diameter of the motor shaft is greater than the diameter of the output half-shaft and also greater than the diameter of the reducer shaft.

13. The electric drive assembly of any one of claims 1 to 12, wherein, The motor also includes a rotor, a stator core, and stator windings; The rotor is sleeved on the motor shaft, the stator core is disposed around the rotor and arranged coaxially with the rotor, and the stator winding is wound on the stator core.

14. The electric drive assembly of claim 13, wherein, The electric drive assembly also includes a motor controller; The motor controller is connected to the stator winding and outputs a pulse width modulation signal to achieve motor control.

15. The electric drive assembly of any one of claims 1 to 12, wherein, The planetary gear reducer also includes a sun gear sleeved on the reducer shaft, a plurality of planet gears meshing with the sun gear, and a gear ring meshing with at least one planet gear. The gear ring is electrically connected to the housing.

16. The electric drive assembly of claim 15, wherein, The planetary gear reducer also includes a planet carrier connected to the motor shaft and the reducer shaft respectively, and the planet carrier is provided with multiple planetary gear shafts; The plurality of planetary gears includes a plurality of primary planetary gears and a plurality of secondary planetary gears; The number of the plurality of planetary gear shafts, the plurality of primary planetary gears, and the plurality of secondary planetary gears are the same, and the plurality of primary planetary gears and the plurality of secondary planetary gears are fitted one-to-one on each of the planetary gear shafts. Each of the primary planetary gears meshes with the sun gear, and each of the secondary planetary gears meshes with the gear ring.

17. An electric vehicle, characterized by Includes a battery and an electric drive assembly as claimed in any one of claims 1 to 16, wherein the battery is used to provide electrical energy to the electric drive assembly.

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