Electric drive system, design method and vehicle

Abstract

The invention provides an electric driving system, a design method and a vehicle, the electric driving system comprises a speed reducer, the speed reducer is provided with an input shaft, the input shaft is provided with a connecting shaft hole, the connecting shaft hole comprises a plurality of hole sections which are sequentially arranged in the axial direction of the connecting shaft hole, and the inner wall of at least one of the plurality of hole sections is provided with an internal spline; the motor is provided with a rotor shaft, part of the rotor shaft is located in the connecting shaft hole, the rotor shaft comprises a plurality of shaft sections which are sequentially arranged in the axial direction of the rotor shaft, an outer spline is arranged on the outer wall of at least one of the shaft sections, a first groove is formed in the shaft section adjacent to the outer spline, and the first groove extends in the circumferential direction of the shaft section; and the energy absorption spring is located in the first assembly cavity. The invention aims to solve the problem of how to effectively buffer clearance collision when the torque suddenly changes on the premise of not influencing the lubricating performance of parts, not occupying extra mounting space and not obviously increasing the cost in the prior art.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric drive, in particular to an electric drive system, a design method and a vehicle. BACKGROUND

[0002] The automobile transmission system is prone to Clunk problem (metallic knocking sound or impact noise) under Tip-in (rapid accelerator) and Tip-out (rapid accelerator release) working conditions. The NVH problem exists in both traditional fuel vehicles and new energy vehicles, and the core cause is the gap collision between gears, splines, half shafts and other components when the torque suddenly changes (positive and negative conversion). The existing avoidance methods have obvious defects: reducing the gap between components easily affects the lubrication performance, leading to serious wear or gluing of gears and splines; although the E-Damper shock absorber can decouple the inertia of the motor rotor through a spring or a hydraulic damping unit to reduce noise, it has a high cost and requires additional installation space.

[0003] At present, there is no effective solution to the above problems. SUMMARY

[0004] The main purpose of the present application is to provide an electric drive system, a design method and a vehicle to effectively buffer the gap collision when the torque suddenly changes without affecting the lubrication performance of the components, without occupying additional installation space and without significantly increasing the cost.

[0005] In order to achieve the above purpose, according to one aspect of the present application, an electric drive system is provided, comprising: a reducer, the reducer having an input shaft, the input shaft being provided with a connecting shaft hole, the connecting shaft hole comprising a plurality of hole sections arranged in sequence along the axial direction thereof, at least one of the plurality of hole sections having an inner spline on the inner wall thereof; a motor, the motor having a rotor shaft, part of the rotor shaft being located in the connecting shaft hole, the rotor shaft comprising a plurality of shaft sections arranged in sequence along the axial direction thereof, at least one of the plurality of shaft sections having an outer spline on the outer wall thereof, a first groove being provided on the shaft section adjacent to the outer spline, the first groove being provided in a circumferential direction of the shaft section, the first groove and the corresponding hole section forming a first assembly cavity when the outer spline is matched with the inner spline; an energy-absorbing spring, the energy-absorbing spring being located in the first assembly cavity, part of the outer wall of the energy-absorbing spring abutting against the inner wall of the corresponding hole section, and part of the inner wall of the energy-absorbing spring abutting against the outer wall of the corresponding shaft section.

[0006] Further, part of the outer wall of the energy-absorbing spring and the outer wall of the energy-absorbing spring are in line contact or surface contact.

[0007] Further, part of the inner wall of the energy-absorbing spring and the outer wall of the corresponding shaft section are in line contact or surface contact.

[0008] Further, the axial section of the energy-absorbing spring is in a wave shape or a sawtooth shape.

[0009] Further, the energy-absorbing spring is provided with a notch for deformation extension.

[0010] Further, the electric drive system further comprises a sealing ring, the rotor shaft is provided with a second groove extending circumferentially along the shaft segment, the first groove is located between the second groove and the outer spline, when the outer spline is matched with the inner spline, the first groove and the corresponding hole segment surround to form a second assembly cavity, the sealing ring is located in the second assembly cavity, part of the sealing ring abuts against the inner wall of the corresponding hole segment, and part of the sealing ring abuts against the outer wall of the corresponding shaft segment.

[0011] Further, the radial section of the sealing ring is circular or polygonal.

[0012] According to another aspect of the present application, a design method of an energy-absorbing spring is provided, the design method is used for designing the energy-absorbing spring, and the design method comprises the following steps: obtaining design core parameters, the design core parameters at least comprise: inertial force when torque is zero, friction coefficient and radial spring size parameters, the radial spring size parameters at least comprise: working height, working width and working length; and determining the structure of the energy-absorbing spring based on the design core parameters.

[0013] Further, the structure of the energy-absorbing spring is determined based on the design core parameters, which comprises: determining the radial force of the elastic element based on the inertial force when torque is zero and the friction coefficient; determining the plate thickness and the elastic modulus of the elastic element based on the radial spring size parameters; determining the wave number and the deformation amount of the elastic element based on the radial force of the elastic element, the plate thickness and the elastic modulus of the elastic element; and determining the structure of the energy-absorbing spring based on the wave number and the deformation amount of the elastic element.

[0014] According to another aspect of the present application, a vehicle is provided, comprising an electric drive system, which is the electric drive system.

[0015] By means of the technical scheme of the present application, the first groove extending circumferentially is arranged on the outer spline adjacent to the shaft segment of the rotor shaft, when the inner spline of the connecting shaft hole of the input shaft of the reducer is matched with the outer spline, the first groove and the corresponding hole segment surround to form the first assembly cavity, and the energy-absorbing spring is arranged in the cavity and abuts against the inner wall of the connecting shaft hole of the input shaft with one wall and abuts against the outer wall of the corresponding shaft segment of the rotor shaft with the other wall, which not only utilizes the elastic deformation of the energy-absorbing spring to effectively buffer the impact load under the working conditions of vehicle starting and stopping, sudden acceleration and deceleration, avoids stress concentration on the matching surface of the outer spline and the inner spline, significantly reduces the wear to prolong the service life of the input shaft and the rotor shaft, but also can absorb vibration energy through the energy-absorbing spring to optimize the NVH performance of the whole vehicle, and solves the problem of how to effectively buffer the gap collision when the torque suddenly changes without affecting the lubrication performance of the components, without occupying additional installation space and without significantly increasing the cost in the prior art. BRIEF DESCRIPTION OF DRAWINGS

[0016] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an implementation of the application and, together with the description, serve to explain the application. In the drawings,

[0017] Figure 1 Structure diagram of the first embodiment of the electric drive system according to the present application;

[0018] Figure 2 Axonometric view of the first embodiment of the input shaft in the electric drive system according to the present application;

[0019] Figure 3 Axonometric view of the first embodiment of the energy-absorbing spring in the electric drive system according to the present application;

[0020] Figure 4 Force analysis diagram of the energy-absorbing spring in the electric drive system according to the present application when the working state is static;

[0021] Figure 5 Force analysis diagram of the energy-absorbing spring in the electric drive system according to the present application when the working state is dynamic.

[0022] 10, input shaft; 20, rotor shaft; 30, energy-absorbing spring; 40, sealing ring; 101, first groove; 102, second groove; 103, external spline; 301, notch. DETAILED DESCRIPTION

[0023] It should be noted that the embodiments and features of the embodiments in the present application can be combined with each other without conflict. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0024] It should be noted that the terms used herein are only intended to describe specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, the singular form is intended to include the plural form unless the context clearly indicates otherwise, and it should also be understood that when the terms "comprise" and / or "include" are used in this specification, there is a presence of the features, steps, operations, devices, components and / or combinations thereof.

[0025] It is to be understood that the terminology "first", "second" and the like used in the specification and the claims of the application as well as the foregoing drawings is merely intended to distinguish between similar objects and not necessarily for describing a special sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments of the application described herein are capable of operation in other sequences than the one(s) described or illustrated herein. Furthermore, the terms "comprise", "comprising", "include", "including", and the like used herein are specifically intended to be construed in an inclusive and not in an exclusive sense. Now, exemplary embodiments according to the present application will be described in more detail with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in various different forms and should not be construed in a limited sense as long as they do not depart from the scope of the present application. It is to be understood that the embodiments are provided merely to make the present disclosure complete and to fully convey the concept of the exemplary embodiments to those skilled in the art, and the drawings are so simplified that the thickness and the area of layers and regions can be exaggerated for the sake of clarity, and the same reference numerals are used to designate the same elements throughout the drawings, and thus a repeated description thereof will be omitted.

[0026] The Clunk problem of the automobile transmission system is a typical NVH problem, which is specifically manifested as metal knocking sound or impact noise of the vehicle in two key working conditions of Tip-in (sudden accelerator) and Tip-out (sudden accelerator loss), and the problem is not specific to a certain vehicle model and is common in the transmission systems of traditional fuel vehicles and new energy vehicles. From the core cause, the root cause lies in that the transmission system will experience a sharp change in torque in the two working conditions, especially when the torque is converted from positive to negative, and there is an inevitable assembly gap between the key transmission components such as gears, splines, half shafts, etc. in the transmission system. The torque mutation will directly cause the rapid collision of these components within the gap range, and the impact generated in the collision process is in the form of metal knocking sound or impact noise as the Clunk problem.

[0027] The current industry's circumvention means for this problem all have obvious technical defects: first, by reducing the assembly gap between the components of the transmission system to reduce the probability of collision, however, the normal operation of the transmission system depends on good lubrication conditions, too small gap will seriously damage the lubrication environment between components, leading to the friction pair such as gears and splines cannot form an effective oil film, and then trigger serious wear problems, in extreme cases, there will be a metal surface gluing failure, greatly shorten the service life of the components; second, use E-Damper shock absorber for noise reduction, the device is usually integrated on the gear, with the help of spring or hydraulic damping unit buffer, the motor rotor inertia is fully decoupled from the transmission system under low load or no load conditions, so as to reduce the energy of gear knocking, thereby realizing noise improvement. But the limitations of this scheme are also prominent, on the one hand, the manufacturing cost of E-Damper shock absorber is relatively higher than other circumvention means, which will increase the manufacturing cost of the vehicle; on the other hand, it has a certain volume, and enough installation space needs to be reserved inside the transmission system, which limits the integrated design of the transmission system.

[0028] The electric drive system provided by the embodiment of the application, as shown in Figures 1-3 The electric drive system provided by the embodiment of the application, as shown in

[0029] By adopting the embodiment, when the rotor shaft 20 is matched with the inner spline of the connecting shaft hole of the input shaft 10, the first recess 101 and the corresponding hole segment form a first assembly cavity, and the energy-absorbing spring 30 is arranged in the cavity and one wall thereof abuts against the inner wall of the connecting shaft hole of the input shaft 10 and the other wall thereof abuts against the outer wall of the corresponding shaft segment of the rotor shaft 20. The elastic deformation of the energy-absorbing spring 30 effectively buffers the impact load under the conditions of vehicle starting and stopping, sudden acceleration and deceleration, avoids stress concentration on the matching surface of the outer spline 103 and the inner spline, significantly reduces wear to prolong the service life of the input shaft 10 and the rotor shaft 20, can absorb vibration energy through the energy-absorbing spring 30 to optimize the NVH performance of the whole vehicle, and the structure does not need to additionally increase the installation space, relies on the existing spline connection layout to realize the energy-absorbing and buffering function, is compact in structure and convenient to assemble, and can guarantee the stability and reliability of power transmission.

[0030] In the embodiment, part of the outer wall of the energy-absorbing spring 30 is in linear or surface contact with the outer wall of the energy-absorbing spring 30.

[0031] By adopting the embodiment, the outer wall of the energy-absorbing spring 30 and the inner wall of the corresponding hole segment of the connecting shaft hole of the input shaft 10 are arranged in linear or surface contact. The force transmission path of the energy-absorbing spring 30 and the input shaft 10 is optimized, stress concentration caused by local point contact is avoided, wear of the contact surface of the energy-absorbing spring 30 and the input shaft 10 is reduced, the service life of the components is prolonged, the installation stability of the energy-absorbing spring 30 in the first assembly cavity is improved, the energy-absorbing spring 30 is prevented from being deviated or shaken during vehicle driving, the buffering and vibration-absorbing effect of the energy-absorbing spring 30 on the impact load of the spline matching part of the rotor shaft 20 and the input shaft 10 is continuously stable, the smoothness of power transmission is further improved in cooperation with the structural design of the first recess 101 and the outer spline 103 of the rotor shaft 20, vibration and noise are effectively reduced, and the reliability and durability of the overall operation of the electric drive system are guaranteed.

[0032] Specifically, part of the inner wall of the energy-absorbing spring 30 is in linear or surface contact with the outer wall of the corresponding shaft segment.

[0033] By adopting the embodiment, the inner wall of the energy-absorbing spring 30 and the outer wall of the corresponding shaft segment of the rotor shaft 20 are designed to be in linear contact or surface contact, and the outer wall of the energy-absorbing spring 30 and the inner wall of the corresponding hole segment of the connecting shaft hole of the input shaft 10 are designed to be in linear contact or surface contact, so that the energy-absorbing spring 30 forms a bidirectional stable contact structure in the first assembly cavity. This not only avoids local stress concentration caused by point contact and effectively reduces the wear of the contact surfaces of the energy-absorbing spring 30, the rotor shaft 20 and the input shaft 10, prolonging the service life of each component, but also further improves the installation and positioning accuracy of the energy-absorbing spring 30, preventing the energy-absorbing spring 30 from deviating or shaking due to bumps or impact loads during vehicle driving, ensuring the continuous and reliable shock-absorbing effect of the energy-absorbing spring 30 on the impact load at the spline outer spline 103 and the spline inner spline of the input shaft 10 and the rotor shaft 20, and optimizing the force transmission through bidirectional contact to make power transmission smoother, further reduce vibration and noise, and cooperate with the first groove 101 structure design of the rotor shaft 20 to comprehensively enhance the stability, smoothness and durability of the electric drive system.

[0034] In one exemplary embodiment, the axial section of the energy-absorbing spring 30 is in a wave shape or a zigzag shape.

[0035] By adopting the embodiment, the axial section of the energy-absorbing spring 30 is designed to be in a wave shape or a zigzag shape, in combination with the first assembly cavity surrounded by the connecting shaft hole of the input shaft 10, the first groove 101 of the rotor shaft 20 and the linear contact or surface contact structure of the energy-absorbing spring 30 with the input shaft 10 and the rotor shaft 20, the elastic deformation capacity and energy absorption efficiency of the energy-absorbing spring 30 are significantly improved, which can more fully buffer the impact load at the spline outer spline 103 and the spline inner spline of the input shaft 10 and the rotor shaft 20. At the same time, the wave shape or zigzag shape structure can disperse the contact stress, avoid fatigue damage caused by excessive local stress of the energy-absorbing spring 30, and prolong its service life; this structure design can also enhance the fitting stability of the energy-absorbing spring 30 in the assembly cavity, ensure the consistency of the shock-absorbing effect under complex vehicle working conditions, further optimize the smoothness of power transmission, reduce vibration and noise, and cooperate with the bidirectional contact layout and spline connection structure to comprehensively improve the operation reliability, durability and vehicle NVH performance of the electric drive system.

[0036] Further, the energy-absorbing spring 30 is provided with a notch 301 for deformation and extension, which is composed of a continuous sinusoidal waveform and is open in a non-working state.

[0037] By setting the notch 301 for deformation extension on the energy-absorbing spring 30, combining the axial wavy or sawtooth cross-section design and the line contact or surface contact structure of the shaft hole connected with the input shaft 10 and the corresponding shaft segment of the rotor shaft 20, the elasticity deformation redundancy and energy absorption efficiency of the energy-absorbing spring 30 are significantly improved, which can more accurately buffer the instantaneous impact load at the fitting place of the outer spline 103 of the rotor shaft 20 and the inner spline of the input shaft 10. At the same time, the notch 301 can disperse the stress concentration in the deformation process, avoid fatigue damage of the energy-absorbing spring 30 due to repeated elastic deformation, and further prolong the service life. The notch 301 design can also adapt to the mounting space formed by the first recess 101 of the rotor shaft 20 and the corresponding hole segment of the input shaft 10, improve the assembly convenience and fitting stability of the energy-absorbing spring 30, ensure the consistency of the buffering and vibration absorption effect under complex working conditions such as vehicle starting and stopping, sudden acceleration and deceleration, and cooperate with the bidirectional contact layout and spline connection structure to not only make the power transmission smoother and effectively reduce the vibration and noise, but also comprehensively enhance the operation reliability, durability and vehicle NVH performance of the electric drive system.

[0038] When the energy-absorbing spring 30 is used, the energy-absorbing spring 30 needs to be installed on the shaft first. Due to the interaction between the rotor shaft 20 and the inner diameter of the energy-absorbing spring 30, the notch 301 of the energy-absorbing spring 30 will gradually expand, and then it is pressed into the hole. The outer diameter of the energy-absorbing spring 30 is tightly fitted with the hole, the notch 301 of the energy-absorbing spring 30 gradually shrinks, and through the radial interference fit and axial limiting, it is ensured that the energy-absorbing spring 30 will not displace or loosen during work.

[0039] Further, the electric drive system further comprises a sealing ring 40, the rotor shaft 20 is provided with a second recess 102, the second recess 102 is arranged in the circumferential direction along the shaft segment, the first recess 101 is located between the second recess 102 and the outer spline 103, when the outer spline 103 is matched with the inner spline, the first recess 101 is surrounded by the corresponding hole segment to form a second assembly cavity, the sealing ring 40 is located in the second assembly cavity, part of the sealing ring 40 abuts against the inner wall of the corresponding hole segment, and part of the sealing ring 40 abuts against the outer wall of the corresponding shaft segment.

[0040] With the embodiment, by adding the second groove 102 extending in the circumferential direction on the rotor shaft 20, and arranging the first groove 101 between the second groove 102 and the outer spline 103, the second groove 102 and the corresponding hole segment form a second assembly cavity when the outer spline 103 is matched with the inner spline of the input shaft 10, and the sealing ring 40 is arranged in the cavity to partially abut the inner wall of the hole segment and the outer wall of the shaft segment, combined with the notch 301 of the energy-absorbing spring 30 and the wavy / sawtooth axial cross-section design, the bidirectional line contact / surface contact structure, not only forms a reliable sealing barrier through the sealing ring 40 to effectively block impurities such as dust and water vapor from entering the matching surface of the outer spline 103 and the inner spline and the first assembly cavity, avoiding the rusting of the energy-absorbing spring 30 and the aggravation of the spline matching surface wear, prolonging the service life of each component, but also realizing the functional partitioning of shock absorption and sealing protection relying on the axial layout of the first groove 101 and the second groove 102, the compact structure does not additionally occupy installation space, ensures that the impact buffering effect of the energy-absorbing spring 30 and the sealing performance of the sealing ring 40 do not interfere with each other and work together, and at the same time improves the overall assembly stability, continuously guarantees the smoothness of power transmission under complex working conditions of the vehicle, further reduces vibration and noise, and comprehensively enhances the operation reliability, durability and overall NVH performance of the electric drive system.

[0041] Specifically, the radial cross-section of the sealing ring 40 is circular or polygonal. After the rotor shaft 20 is inserted into the connecting shaft hole of the input shaft 10, the outer spline 103 is matched with the inner spline to make the energy-absorbing spring 30 in the first assembly cavity formed by the first groove 101 and the corresponding hole segment, the outer wall and the inner wall of which are in line contact or surface contact with the inner wall of the corresponding hole segment and the outer wall of the shaft segment, respectively, and the axial cross-section of the energy-absorbing spring 30 is wavy or sawtooth-shaped and is provided with a notch 301, which can efficiently buffer the gap collision when the torque suddenly changes to suppress the Clunk problem; at the same time, the radial cross-section of the sealing ring 40 in the second assembly cavity formed by the second groove 102 of the rotor shaft 20 and the corresponding hole segment is circular or polygonal to adapt to different assembly requirements, and part of it abuts the inner wall of the corresponding hole segment and the outer wall of the shaft segment to realize reliable sealing and guarantee the stability of the internal environment; the overall gap between the components does not need to be reduced to avoid wear caused by poor lubrication.

[0042] According to another specific embodiment of the present application, a design method of an energy-absorbing spring is also provided, the design method is used for designing the above-mentioned energy-absorbing spring, and the design method comprises the following steps:

[0043] Step S1, obtaining design core parameters;

[0044] In step S1, the design core parameters at least include: inertia force when the torque is zero, friction coefficient and radial spring size parameters, and the radial spring size parameters at least include: working height, working width and working length;

[0045] Step S2, determining the structure of the energy-absorbing spring based on the design core parameters.

[0046] In step S2, the working state force analysis is as shown in Figure 4 The shaft and hole provide multi-directional radial force P around the central axis, and the force analysis when the positive and negative torque of the transmission system suddenly changes is as shown in Figure 5 The energy-absorbing spring 30 provides a friction torque in the opposite direction of the movement direction or movement trend, and through this opposite direction friction torque, the energy-absorbing spring 30 can effectively slow down the impact of torque mutation on the transmission system. The elastic element is designed according to the design input to calculate the radial force P that the elastic element needs to provide, and the formula is as follows:

[0047] (1);

[0048] Wherein, P is the radial force, unit is N; μ is the friction coefficient; F is the inertia force when the torque is zero, unit is N;

[0049] After determining the radial force P required by the energy-absorbing spring 30 in the working state, the next step is to determine the structure parameters and material selection. The key parameters such as the working height, width b and length L of the radial spring need to be determined in combination with the actual arrangement space structure, and the appropriate plate material is selected according to this. The selection of the plate material needs to consider the thickness t and the elastic modulus E of the material itself, and needs to be reasonably arranged in the assembly while meeting the strength performance.

[0050] After the structure parameters are determined, the wave number (N) and deformation (f) of the sample are designed according to the calculation formula of the deformation f and the radial force P, and the formula is as follows:

[0051] (2);

[0052] Wherein f is the deformation in the working state, equal to the free height minus the working height, unit is mm; L is the length of the radial spring, unit is mm; E is the elastic modulus of the material, unit is Pa; b is the width of the radial spring, unit is mm; t is the thickness of the radial spring plate, unit is mm; N is the number of waves, and one wave is from one wave height to another wave height.

[0053] Further, based on the core design parameters, the structure of the energy-absorbing spring is determined, including: based on the inertia force when the torque is zero and the friction coefficient, the radial force of the elastic element is determined; based on the size parameters of the radial spring, the plate thickness of the elastic element and the elastic modulus of the elastic element are determined; based on the radial force of the elastic element, the plate thickness of the elastic element and the elastic modulus of the elastic element, the wave number of the elastic element and the deformation of the elastic element are determined; based on the wave number of the elastic element and the deformation of the elastic element, the structure of the energy-absorbing spring is determined.

[0054] With the embodiment, the structure design of the energy-absorbing spring 30 is precisely matched based on core parameters. First, the radial force of the elastic element of the energy-absorbing spring 30 is determined based on the inertial force and the friction coefficient when the torque is zero. Then, the thickness and the elastic modulus of the elastic element are determined in combination with the radial size parameters of the energy-absorbing spring 30. Subsequently, the wave number and the deformation of the elastic element are determined based on the radial force, the thickness and the elastic modulus of the elastic element. Finally, the structure of the energy-absorbing spring 30 is determined, so that the energy-absorbing spring 30 can be precisely matched with the matching scene of the rotor shaft 20 and the input shaft 10. When the outer wall and the inner wall of the energy-absorbing spring 30 respectively abut against the inner wall of the corresponding hole segment and the outer wall of the shaft segment, the energy-absorbing spring 30 can efficiently buffer the gap collision caused by the sudden change of torque, and effectively suppress the Clunk problem. At the same time, without reducing the gap between components, the gear and spline wear or gluing caused by poor lubrication is avoided. Compared with the E-Damper shock absorber, the cost is lower and no additional installation space is needed. In the second assembly cavity formed by the second groove 102 of the rotor shaft 20 and the corresponding hole segment, the sealing ring 40 with a circular or polygonal radial cross section is used to achieve reliable sealing, further improving the reliability and adaptability of the entire electric drive system.

[0055] According to another specific embodiment of the present application, a vehicle is also provided, comprising an electric drive system, which comprises the above electric drive system.

[0056] With the embodiment, the vehicle is equipped with the electric drive system, and reliable power transmission is achieved by the spline outer spline 103 and the spline inner spline of the input shaft 10 and the rotor shaft 20. In combination with the energy-absorbing spring 30 with the notch 301, the wavy / sawtooth axial cross section and the line contact / surface contact design in the first assembly cavity surrounded by the first groove 101 and the corresponding hole segment, the impact load under the vehicle start-stop, sudden acceleration and deceleration and other working conditions is effectively buffered, the spline fitting surface wear and vibration noise are reduced. At the same time, the circular / polygonal cross section sealing ring 40 in the second assembly cavity surrounded by the second groove 102 and the corresponding hole segment forms reliable sealing protection to avoid the intrusion of impurities, which significantly improves the smoothness of vehicle power transmission and the overall vehicle NVH performance, prolongs the service life of the core components of the electric drive system, such as the input shaft 10, the rotor shaft 20, the energy-absorbing spring 30 and the sealing ring 40, and enhances the operation reliability and durability of the vehicle under complex road conditions, further optimizes the driving experience and overall performance of the vehicle.

[0057] For purposes of the description hereinafter, the terms "upper", "lower", "right", "left", "rear", "front", "vertical", "horizontal", and derivatives thereof (e.g., "vertical ly", "horizontal ly", etc.) can refer to the relative positions of an apparatus or feature as shown in the drawings, and shall not be construed as limiting the present application to any particular spatial orientation. Furthermore, the terms "first", "second", third", etc. merely identify one of a number of similar features or steps in an embodiment, and are not intended to denote a spatial or chronological priority of such features or steps to one another. The terms "comprise", "comprising", "include", "including", and the like, as used herein, are specifically intended to be construed as open-ended terms (i.e., the terms do not exclude the presence of other elements or steps). It is specifically intended that any total number or range of steps or components to be

[0058] In addition, it should be understood that any numerical range recited herein includes all values from the lower and upper limits of that range. For example, if a concentration range is stated as 1% to 50%, it is intended that values ranging from 1% to 50%, such as 20%, are expressly enumerated. It is also understood that the endpoints of the ranges are not significant and are intended to be merely approximate. It is also understood that the description is not limited in scope to the specific embodiments described herein, which are intended for illustrative purposes only. Any change of numerical limitations, such as concentration ranges, temperature ranges, etc., are intended to be included in the scope of the present application.

[0059] In the above embodiments, the description of each embodiment is focused on a certain aspect. The description of a certain embodiment can be referred to for the description of other embodiments.

[0060] The preferred embodiments of the application are shown and described above. The present application may, however, be embodied in various ways without departing from the spirit or essential characteristic thereof. Therefore, the disclosures and descriptions herein are not intended to limit the scope of the application, but rather are intended to be exemplary embodiments thereof. It will be understood by those skilled in the art that various changes can be made and equivalents can be substituted for elements thereof without departing from the scope of the application. It will be understood that any changes, modifications, substitutions, and other alternatives are intended to fall within the scope of the application.

Claims

1. An electric drive system, characterized by The electric drive system comprises: a reducer having an input shaft (10) provided with a connecting shaft hole comprising a plurality of hole sections arranged in sequence along the axial direction, at least one of the plurality of hole sections having an inner spline on the inner wall thereof; a motor having a rotor shaft (20), part of the rotor shaft (20) being located in the connecting shaft hole, the rotor shaft (20) comprising a plurality of shaft sections arranged in sequence along the axial direction, at least one of the plurality of shaft sections having an outer spline (103) on the outer wall thereof, the outer spline (103) being provided with a first groove (101) on the adjacent shaft section, the first groove (101) being arranged in a circumferential direction along the shaft section, and the outer spline (103) being matched with the inner spline, the first groove (101) and the corresponding hole section surrounding to form a first assembly cavity; an energy-absorbing spring (30) located in the first assembly cavity, part of the outer wall of the energy-absorbing spring (30) abutting against the inner wall of the corresponding hole section, and part of the inner wall of the energy-absorbing spring (30) abutting against the outer wall of the corresponding shaft section.

2. The electric drive system of claim 1, wherein, Part of the outer wall of the energy-absorbing spring (30) is in linear or surface contact with the outer wall of the energy-absorbing spring (30).

3. The electric drive system of claim 2, wherein, Part of the inner wall of the energy-absorbing spring (30) is in linear or surface contact with the outer wall of the corresponding shaft section.

4. The electric drive system according to any one of claims 1-3, characterized in that, The axial section of the energy-absorbing spring (30) is in a wave shape or a sawtooth shape.

5. The electric drive system of claim 4, wherein, The energy-absorbing spring (30) is provided with a notch (301) for deformation extension.

6. The electric drive system of claim 5, wherein, The electric drive system further comprises: a sealing ring (40), the rotor shaft (20) being provided with a second groove (102) arranged in a circumferential direction along the shaft section, the first groove (101) being located between the second groove (102) and the outer spline (103), the outer spline (103) being matched with the inner spline, the first groove (101) and the corresponding hole section surrounding to form a second assembly cavity, the sealing ring (40) being located in the second assembly cavity, part of the sealing ring (40) abutting against the inner wall of the corresponding hole section, and part of the sealing ring (40) abutting against the outer wall of the corresponding shaft section.

7. The electric drive system of claim 6, wherein, The radial section of the sealing ring (40) is in a circular or polygonal shape.

8. A method of designing an energy absorbing spring, characterized by The design method is used for designing the energy-absorbing spring in the electric drive system of any one of claims 1-7, and the design method comprises the following steps: obtaining design core parameters, the design core parameters at least comprising: an inertial force at torque zero, a friction coefficient, and radial spring size parameters, the radial spring size parameters at least comprising: a working height, a working width, and a working length; determining the structure of the energy-absorbing spring based on the design core parameters.

9. The design method of claim 8, wherein, Determining the structure of the energy-absorbing spring based on the design core parameters comprises: determining an elastic element radial force based on the inertial force at torque zero and the friction coefficient; determining an elastic element plate thickness and an elastic element elastic modulus based on the radial spring size parameters; determining the wave number and the deformation of the elastic element based on the radial force of the elastic element, the thickness of the elastic element plate, and the elastic modulus of the elastic element; determining the structure of the energy-absorbing spring based on the wave number and the deformation of the elastic element.

10. A vehicle comprising an electric drive system, characterized in that The electric drive system is the electric drive system of any one of claims 1-7.

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