A coaxial single-motor three-speed sequential shift electric drive axle system

Abstract

The present invention relates to a coaxial single-motor three-speed sequential shift electric drive axle system, comprising a drive motor, a three-speed planetary reduction mechanism, a shift mechanism and a differential assembly. The technical solution of the present invention utilizes only a three-stage series-connected planetary gearbox to achieve high torque output and high-speed operation. Simultaneously, only one shift actuator and shift gear sleeve are utilized to achieve sequential switching of three gears without power interruption, thereby greatly improving the transmission efficiency of the electric drive axle system and reducing the cost of the entire machine.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle power systems, and in particular to a coaxial single-motor three-speed sequential shift electric drive axle system. Background Art

[0002] At present, pure electric-driven heavy-duty commercial trucks mostly use two drive methods: central electric drive and electric drive axle to achieve vehicle power transmission, and the electric drive axle has gradually become a development trend.

[0003] An e-axle, also known as a distributed electric drive, involves mounting the electric motor directly on the vehicle's wheel hub or axle, enabling each wheel to independently drive. A single-motor e-axle, also known as a single-axle electric drive system, involves a single electric motor directly driving the wheels on a single axle.

[0004] Single-motor e-axle layouts are mostly offset parallel axis and coaxial. In the coaxial arrangement, the motor and reducer are mounted on the same axis of the vehicle, usually perpendicular to the wheel axle. The motor is directly connected to the reducer, which then transmits power to the wheels.

[0005] Coaxial electric drive axles are often arranged with a dual intermediate shaft and planetary gear set, or a full planetary gear set, but typically feature a single or two-speed configuration. Prior art suggests a coaxial two-speed integrated electric drive axle with a three-stage series planetary gear set, where only the third stage allows for two-speed shifting. Two planetary gear sets are also deployed at the wheel ends to increase speed ratio and torque.

[0006] However, the problems with the above structure are also obvious. It can only realize the layout switching of two gears, and when increasing the wheel-end torque, it is necessary to add a side wheel planetary gear to achieve it. This will lead to low system transmission efficiency, structural redundancy, and inability to take into account high-torque climbing and high-speed operation of multi-gear / low-cost electric heavy-duty truck scenarios. Summary of the Invention

[0007] The invention discloses a coaxial single-motor three-speed sequential shift electric drive axle system, aiming to solve the technical problems existing in the prior art.

[0008] The present invention adopts the following technical solutions:

[0009] An embodiment of the present invention provides a coaxial single-motor three-speed sequential shift electric drive axle system, comprising:

[0010] - a drive motor including an input shaft;

[0011] - A three-speed planetary reduction mechanism comprising a first-stage planetary gear set, a second-stage planetary gear set, and a third-stage planetary gear set connected in series. The first-stage planetary gear set comprises first-stage ring gear dog teeth and first-stage planet carrier dog teeth, and is drivingly connected to the input shaft. The second-stage planetary gear set comprises second-stage ring gear dog teeth and second-stage planet carrier dog teeth.

[0012] - a shift mechanism including a shift sleeve having first, second, third and fourth dog teeth;

[0013] The first gear sleeve dog teeth and the second gear sleeve dog teeth can be engaged with the second-stage ring gear dog teeth and the first-stage ring gear dog teeth respectively at the same time to achieve first gear transmission; the third gear sleeve dog teeth and the second gear sleeve dog teeth can be engaged with the second-stage planetary carrier dog teeth and the first-stage ring gear dog teeth respectively at the same time to achieve second gear transmission; the fourth gear sleeve dog teeth and the second gear sleeve dog teeth can be engaged with the first-stage planetary carrier dog teeth and the first-stage ring gear dog teeth respectively at the same time to achieve third gear transmission;

[0014] -The differential assembly includes a differential, a first output half-shaft, and a second output half-shaft. The third-stage planetary carrier is connected to the differential. The power output of the third-stage planetary gear is output to the first output half-shaft and the second output half-shaft through the differential. The first output half-shaft and the second output half-shaft are coaxial.

[0015] As a preferred technical solution, the first-stage planetary gear also includes a first-stage sun gear, a first-stage planetary gear, a first-stage ring gear and a first-stage planetary carrier; the second-stage planetary gear also includes a second-stage sun gear, a second-stage planetary gear, a second-stage ring gear and a second-stage planetary carrier; the third-stage planetary gear also includes a third-stage sun gear, a third-stage planetary gear, a third-stage ring gear and a third-stage planetary carrier.

[0016] As a preferred technical solution, when in the first gear transmission state, the first-stage ring gear, the second-stage ring gear and the third-stage ring gear are all locked.

[0017] As an optimal technical solution, the second gear sleeve dog teeth can engage with the first-stage ring gear dog teeth, and the second-stage planetary carrier dog teeth can be located between the third gear sleeve dog teeth and the fourth gear sleeve dog teeth, realizing first gear shifting to neutral.

[0018] As a preferred technical solution, when in the second gear transmission state, the first-stage planetary gear is coupled with the second-stage planetary gear, and the first-stage ring gear and the first-stage planetary carrier respectively input power to the second-stage planetary carrier and the second-stage sun gear.

[0019] As an optimal technical solution, the second gear sleeve dog teeth can engage with the first-stage ring gear dog teeth, and the third gear sleeve dog teeth and the fourth gear sleeve dog teeth can be located between the second-stage planetary carrier dog teeth and the first-stage planetary carrier dog teeth, realizing the second gear shift to neutral.

[0020] As a preferred technical solution, when in the third gear transmission state, the first-stage planetary gear is self-locked as a whole and outputs power.

[0021] As a preferred technical solution, the differential includes a differential case, a cross shaft, a planetary driving gear and a planetary driven gear. The differential case is transmission-connected to the third-stage planetary gear, and the planetary driven gear is transmission-connected to the first output half-shaft and the second output half-shaft respectively.

[0022] As a preferred technical solution, the shift mechanism further includes a shift actuator and a shift fork. The shift actuator can drive the shift fork and the shift gear sleeve to achieve switching between three shift positions.

[0023] As a preferred technical solution, the first output half-shaft and the second output half-shaft are respectively transmission-connected to the wheel ends.

[0024] One embodiment of the above invention has the following advantages or beneficial effects:

[0025] The present invention mainly provides a coaxial single-motor three-speed sequential shifting electric drive axle system. Compared with the existing technology, the embodiment of the present invention only uses three-stage series planetary gears to achieve high torque output and high-speed operation. At the same time, only one shift actuator and shift gear sleeve are used to achieve sequential switching of three gears without power interruption, which greatly improves the transmission efficiency of the electric drive axle system and reduces the cost of the entire machine. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments, which constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are provided to explain the present invention and do not constitute an undue limitation of the present invention. In the drawings:

[0027] Figure 1 A schematic structural diagram of a coaxial single-motor three-speed sequential shift electric drive axle system according to one embodiment of the present invention;

[0028] Figure 2 A schematic diagram of the subsystem structure of a coaxial single-motor three-speed sequential shift electric drive axle system provided by one embodiment of the present invention;

[0029] Figure 3 A schematic structural diagram of a shift mechanism provided by one embodiment of the present invention;

[0030] Figure 4 A schematic diagram of a sequential shifting sequence provided by an embodiment of the present invention;

[0031] Figure 5 A schematic diagram of the power flow of the first gear (G1) provided by one embodiment of the present invention;

[0032] Figure 6 A schematic diagram of the power flow of the second gear (G2) provided by an embodiment of the present invention;

[0033] Figure 7 A schematic diagram of the third gear (G3) power flow provided by an embodiment of the present invention.

[0034] Description of reference numerals:

[0035] Drive motor 100, stator 110, coil 120, rotor 130, rotor shaft 140;

[0036] First-stage planetary gear 200, first-stage sun gear 210, first-stage planetary gear 220, first-stage planet carrier 230, first-stage planet carrier dog teeth 231, first-stage ring gear 240, first-stage ring gear dog teeth 241;

[0037] Second-stage planetary gear 300, second-stage sun gear 310, second-stage planetary gear 320, second-stage planet carrier 330, second-stage planet carrier dog teeth 331, second-stage ring gear 340, second-stage ring gear dog teeth 341;

[0038] A third-stage planetary gear 400, a third-stage sun gear 410, a third-stage planetary gear 420, a third-stage planetary carrier 430, and a third-stage ring gear 440;

[0039] Shift mechanism 500, shift actuator 510, shift fork 520, shift sleeve 530, first sleeve dog teeth 531, second sleeve dog teeth 532, third sleeve dog teeth 533, fourth sleeve dog teeth 534;

[0040] Differential 600, differential housing 610, cross shaft 620, planetary driving gear 630, planetary driven gear 640;

[0041] First output half shaft 700 ; second output half shaft 800 . DETAILED DESCRIPTION

[0042] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments of the present invention and corresponding drawings. In the description of the present invention, it should be noted that the term "or" is generally used in the sense of including "and / or" unless the content clearly indicates otherwise.

[0043] Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0044] To meet the demands for high torque output, independent control, active torque vectoring, and fault tolerance, electric axles have become one of the most common drive systems for all-electric heavy-duty commercial trucks. Increasing the number of gears not only increases the number and complexity of components such as motors, sensors, and controllers, thereby increasing system cost and maintenance, but also increases energy conversion losses and consumption. Therefore, coaxial electric axles often use a single or two-speed arrangement.

[0045] To solve the above problems, refer to Figure 1-3 The embodiment of the present invention provides a coaxial single-motor three-speed sequential shift electric drive axle system, which is intended to simultaneously take into account the performance of high-torque climbing and high-speed operation, so that electric heavy-duty trucks can achieve optimal power performance and energy efficiency under different road conditions and working conditions.

[0046] In a preferred embodiment, a coaxial single-motor three-speed sequential shift electric drive axle system includes a drive motor 100, a three-speed planetary reduction structure, a shift mechanism 500 and a differential 600 assembly, wherein the drive motor 100 is used to provide power for the system, and the three-speed planetary reduction mechanism includes three-stage planetary gears connected in series, which, in conjunction with the shift mechanism 500, can achieve torque amplification and multi-speed shifting, and output power to the differential 600 assembly, which ultimately outputs the power to the wheels to achieve high-speed operation and large torque output.

[0047] In a preferred embodiment, the drive motor 100 includes a stator 110, a coil, a rotor 130, and a rotor shaft 140. The rotor shaft 140 serves as an input shaft, transmitting the torque generated by the drive motor 100 to the third-speed planetary reduction mechanism. In this embodiment, the specific model, structure, or specifications of the drive motor 100 are not limited; those skilled in the art may freely select one based on the actual needs of the electric heavy-duty truck.

[0048] In a preferred embodiment, the three-speed planetary reduction mechanism includes a first-stage planetary gear 200, a second-stage planetary gear 300, and a third-stage planetary gear 400 that are sequentially connected in series.

[0049] Preferably, the first-stage planetary gear set 200 is transmission-connected to the rotor shaft 140 of the drive motor 100. The first-stage planetary gear set 200 includes a first-stage sun gear 210, a first-stage planetary gear 220, a first-stage planetary carrier 230 and a first-stage ring gear 240. The first-stage ring gear 240 and the first-stage planetary carrier 230 are respectively provided with first-stage ring gear dog teeth 241 and first-stage planetary carrier dog teeth 231.

[0050] Preferably, the second-stage planetary gear 300 includes a second-stage sun gear 310 , second-stage planetary gears 320 , a second-stage planetary carrier 330 and a second-stage ring gear 340 . Second-stage ring gear dog teeth 341 and second-stage planetary carrier dog teeth 331 are respectively provided on the second-stage ring gear 340 and the second-stage planetary carrier 330 .

[0051] Preferably, the third-stage planetary gear 400 includes a third-stage sun gear 410 , third-stage planetary gears 420 , a third-stage planet carrier 430 and a third-stage ring gear 440 .

[0052] Specifically, regardless of the planetary gear stage, the sun gear is located in the middle of the planetary gear structure, and the sun gear can be engaged with the ring gear through the planet gears. The planet gears are arranged around the sun gear, with their inner sides engaged with the sun gear and their outer sides engaged with the gear sleeve. They are connected to the planet carrier through rollers or bearings. There are usually multiple planet gears, evenly distributed around the planet carrier. The planet carrier is the support structure for connecting the planet gears. There are multiple holes on the planet carrier, and a planet gear is installed in each hole to support the planet gears and ensure their normal movement. The ring gear surrounds the sun gear and planet gears and is nested with the planet gear teeth to form a complete transmission circuit. By changing the relative operating relationship of the various structures in the planetary gear, different speed ratios and torque outputs can be achieved. Examples are not listed here one by one.

[0053] In a preferred embodiment, the shift mechanism 500 includes a shift actuator 510, a shift fork 520 and a shift sleeve 530, wherein the shift sleeve 530 has a first sleeve dog teeth 531, a second sleeve dog teeth 532, a third sleeve dog teeth 533 and a fourth sleeve dog teeth 534, and the sleeve dog teeth can engage with the corresponding dog teeth in the planetary gear set for connecting and disconnecting the transmission force.

[0054] In a preferred embodiment, the differential 600 assembly includes a differential 600, a first output half-shaft 700 and a second output half-shaft 800. The differential 600 includes a differential case 610, a cross shaft 620, a planetary driving gear 630 and a planetary driven gear 640. The differential case 610 is transmission-connected to the third-stage planetary gear 400, and the planetary driven gear 640 is transmission-connected to the first output half-shaft 700 and the second output half-shaft 800 respectively, and can output power to the first output half-shaft 700 and the second output half-shaft 800. The first output half-shaft 700 and the second output half-shaft 800 drive the corresponding wheels to achieve driving.

[0055] In a preferred embodiment, when the first gear sleeve dog teeth 531 are engaged with the second stage gear ring dog teeth 341, and the second gear sleeve dog teeth 532 are engaged with the first stage gear sleeve dog teeth, the first stage gear ring 240 can be locked. At this time, the gear rings of the three-stage planetary gear set are all locked, and the first gear (G1) transmission can be achieved. Figure 4 .

[0056] refer to Figure 1 Preferably, when in the first gear transmission state, the power flow of the entire system is as follows: the rotor shaft 140 inputs power and power and transmits it to the first-stage sun gear 210. Since the first-stage ring gear 240 is locked, the power and power are transmitted from the first-stage planetary carrier 230 to the second-stage sun gear 310, and then from the second-stage planetary carrier 330 to the third-stage sun gear 410, and then from the third-stage planetary carrier 430 to the differential case 610, and finally from the cross shaft 620, the planetary driving gear 630, and the planetary driven gear 640 in the differential 600 to the first output half-shaft 700 and the second output half-shaft 800 (i.e., the left half-shaft and the right half-shaft), respectively, and then the power and power are transmitted to the wheel end.

[0057] In a preferred embodiment, when only the second gear sleeve dog teeth 532 on the shift sleeve 530 are engaged with the first stage ring gear dog teeth 241, and the second stage planetary carrier dog teeth 331 are located between the third gear sleeve dog teeth 533 and the fourth gear sleeve dog teeth 534, it is possible to shift from first gear (G1) to neutral (N), such as Figure 4 At this time, the first-stage sun gear 210, the first-stage planetary gear 220, and the first-stage ring gear 240 in the first-stage planetary gear 200 are not locked, and there is no power output.

[0058] In a preferred embodiment, when the third gear sleeve dog teeth 533 are engaged with the second stage planet carrier dog teeth 331 and the second gear sleeve dog teeth 532 are engaged with the first stage ring gear dog teeth 241, the second gear (G2) transmission is achieved. Figure 4 At this time, the first-stage planetary gear 200 is coupled to the second-stage planetary gear 300, and the first-stage ring gear 240 and the first-stage planetary carrier 230 respectively input power to the second-stage planetary carrier 330 and the second-stage sun gear 310.

[0059] refer to Figure 6 Preferably, when in the second gear transmission state, the power flow of the entire system is as follows: the rotor shaft 140 inputs power and power to the first-stage sun gear 210. Since the first-stage planetary gear 200 and the second-stage planetary gear 300 are coupled, and the first-stage ring gear 240 and the first-stage planetary carrier 230 respectively input power and power to the second-stage planetary carrier 330 and the second-stage sun gear 310, the power is then transmitted by the second-stage planetary carrier 330 to the third-stage sun gear 410, and then transmitted by the third-stage planetary carrier 430 to the differential case 610, and finally output by the cross shaft 620, the planetary driving gear 630 and the planetary driven gear 640 in the differential 600 to the first output half shaft 700 and the second output half shaft 800 respectively, and then the power is transmitted to the wheel end.

[0060] In a preferred embodiment, when only the second gear sleeve dog teeth 532 on the shift sleeve 530 are engaged with the first stage ring gear dog teeth 241, and the third gear sleeve dog teeth 533 and the fourth gear sleeve dog teeth 534 are located between the second stage planet carrier dog teeth 331 and the first stage planet carrier dog teeth 231, it is possible to shift from second gear (G2) to neutral (N), such as Figure 4 At this time, the first-stage sun gear 210, the first-stage planetary gear 220, and the first-stage ring gear 240 in the first-stage planetary gear 200 are not locked, and there is no power output.

[0061] In a preferred embodiment, when the fourth gear sleeve dog teeth 534 are engaged with the first stage planet carrier dog teeth 231 and the second gear sleeve dog teeth 532 are engaged with the first stage ring gear dog teeth 241, the system can achieve third gear (G3) transmission, such as Figure 4 At this time, the first-stage planetary gear 200 is self-locked as a whole and outputs power.

[0062] refer to Figure 7 Preferably, when in the third gear transmission state, the power flow of the entire system is as follows: the rotor shaft 140 inputs power and power and transmits it to the first-stage sun gear 210. Since the first-stage planetary row 200 is self-locked as a whole, the power and power are transmitted from the first-stage planetary carrier 230 to the second-stage sun gear 310, and then from the second-stage planetary carrier 330 to the third-stage sun gear 410, and then from the third-stage planetary carrier 430 to the differential case 610, and finally from the cross shaft 620, the planetary driving gear 630, and the planetary driven gear 640 in the differential 600 to the first output half shaft 700 and the second output half shaft 800 respectively, and then the power and power are transmitted to the wheel end.

[0063] Compared with the existing technology, the present invention can achieve high torque output and high speed operation by only using a three-stage planetary gearbox. At the same time, it can realize sequential switching of three gears without power interruption by only using one shift actuator and shift gear sleeve, which greatly improves the transmission efficiency of the electric drive axle system and reduces the cost of the whole machine.

[0064] Although example embodiments have been described herein with reference to the accompanying drawings, it should be understood that the above example embodiments are merely illustrative and are not intended to limit the scope of the present application. Various changes and modifications may be made therein by those skilled in the art without departing from the scope and spirit of the present application. All such changes and modifications are intended to be included within the scope of the present application as required by the appended claims.

[0065] In the description provided herein, a large number of specific details are described. However, it is understood that the embodiments of the present application can be practiced without these specific details. In some instances, well-known methods, structures, and techniques are not shown in detail so as not to obscure the understanding of this description.

[0066] Similarly, it should be understood that in order to streamline the present application and aid in understanding one or more of the various inventive aspects, in the description of the exemplary embodiments of the present application, the various features of the present application are sometimes grouped together into a single embodiment, figure, or description thereof. However, this approach of the present application should not be interpreted as reflecting the intention that the application claimed for protection requires more features than those explicitly recited in each claim. More precisely, as reflected in the corresponding claims, the inventive point is that the corresponding technical problem can be solved with fewer features than all the features of a single disclosed embodiment. Therefore, the claims following the detailed description are hereby expressly incorporated into the detailed description, with each claim itself serving as a separate embodiment of the present application.

[0067] Those skilled in the art will understand that, except where mutually exclusive, all features disclosed in this specification (including the accompanying claims, abstract, and drawings), as well as all processes or units of any method or apparatus disclosed herein, may be combined in any combination. Unless expressly stated otherwise, each feature disclosed in this specification (including the accompanying claims, abstract, and drawings) may be replaced by an alternative feature that provides the same, equivalent, or similar purpose.

Claims

1. A coaxial single-motor three-speed sequential shift electric drive axle system, characterized in that: include: - a drive motor including an input shaft; - a three-speed planetary reduction mechanism comprising a first-stage planetary gear set, a second-stage planetary gear set, and a third-stage planetary gear set connected in series, wherein the first-stage planetary gear set comprises a first-stage ring gear, first-stage ring gear dog teeth, a first-stage planetary carrier, and first-stage planetary carrier dog teeth, the first-stage planetary gear set being drivingly connected to the input shaft, the second-stage planetary gear set comprises a second-stage sun gear, a second-stage ring gear, second-stage ring gear dog teeth, a second-stage planetary carrier, and second-stage planetary carrier dog teeth; and the third-stage planetary gear set comprises a third-stage ring gear; - a shift mechanism, comprising a shift sleeve, wherein the shift sleeve has first sleeve dog teeth, second sleeve dog teeth, third sleeve dog teeth and fourth sleeve dog teeth; The first gear sleeve dog teeth and the second gear sleeve dog teeth can be respectively engaged with the second-stage ring gear dog teeth and the first-stage ring gear dog teeth at the same time to achieve first gear transmission; the third gear sleeve dog teeth and the second gear sleeve dog teeth can be respectively engaged with the second-stage planetary carrier dog teeth and the first-stage ring gear dog teeth at the same time to achieve second gear transmission; the fourth gear sleeve dog teeth and the second gear sleeve dog teeth can be respectively engaged with the first-stage planetary carrier dog teeth and the first-stage ring gear dog teeth at the same time to achieve third gear transmission; - a differential assembly, comprising a differential, a first output half-shaft, and a second output half-shaft, the third-stage planetary gear set being connected to the differential, the power output by the third-stage planetary gear set being output to the first output half-shaft and the second output half-shaft through the differential, the first output half-shaft and the second output half-shaft being coaxial; When in the first gear transmission state, the first-stage ring gear, the second-stage ring gear and the third-stage ring gear are all locked; When in the second-gear transmission state, the first-stage planetary gear is coupled to the second-stage planetary gear, and the first-stage ring gear and the first-stage planetary carrier respectively input power to the second-stage planetary carrier and the second-stage sun gear; When in the third gear transmission state, the first-stage planetary gear is self-locked as a whole and outputs power.

2. The coaxial single-motor three-speed sequential shift electric drive axle system according to claim 1, characterized in that: The first-stage planetary gear train also includes a first-stage sun gear and a first-stage planetary gear; the second-stage planetary gear train also includes a second-stage planetary gear; the third-stage planetary gear train also includes a third-stage sun gear, a third-stage planetary gear and a third-stage planet carrier.

3. The coaxial single-motor three-speed sequential shift electric drive axle system according to claim 1, characterized in that: The second gear sleeve dog teeth can be engaged with the first stage ring gear dog teeth, and the second stage planet carrier dog teeth can be located between the third gear sleeve dog teeth and the fourth gear sleeve dog teeth, realizing a first gear shift to neutral.

4. The coaxial single-motor three-speed sequential shift electric drive axle system according to claim 1, characterized in that: The second gear sleeve dog teeth can engage with the first stage ring gear dog teeth, and the third gear sleeve dog teeth and the fourth gear sleeve dog teeth can be located between the second stage planet carrier dog teeth and the first stage planet carrier dog teeth to achieve second gear neutral shift.

5. The coaxial single-motor three-speed sequential shift electric drive axle system according to claim 1, characterized in that: The differential includes a differential housing, a cross shaft, a planetary driving gear and a planetary driven gear. The differential housing is transmission-connected to the third-stage planetary gear set, and the planetary driven gear is transmission-connected to the first output half shaft and the second output half shaft respectively.

6. The coaxial single-motor three-speed sequential shift electric drive axle system according to claim 1, characterized in that: The shift mechanism further comprises a shift actuator and a shift fork, wherein the shift actuator can drive the shift fork and the shift gear sleeve to switch between three shift positions.

7. The coaxial single-motor three-speed sequential shift electric drive axle system according to claim 1, characterized in that: The first output half shaft and the second output half shaft are drivingly connected to the wheel ends respectively.

Images