Novel power system structure for electric drive axle

Abstract

The invention discloses a novel power system structure for an electric drive axle, which comprises a speed reducer system, a differential mechanism system and a speed change system which are integrated into a whole, the driving wheel is meshed with the motor shaft through a spline; the driven wheel is meshed with the driving wheel; the driven wheel output shaft is fixedly arranged in the driven wheel, and an internal spline is arranged in the driven wheel output shaft; the sun gear is meshed with the internal spline of the output shaft of the driven gear; the planet gear is arranged outside the sun gear and meshed with the sun gear; the planetary gear is sleeved with the inner gear ring, and the inner gear ring is meshed with the planetary gear; the differential mechanism shell is connected with the differential mechanism support and the rear differential mechanism shell gear cover, and the differential mechanism support and the rear differential mechanism shell gear cover are arranged on the two sides of the inner gear ring respectively. The inner gear ring bracket is connected with the differential bracket; the differential planet wheel is meshed with the differential half axle gear; the speed change system achieves the speed change function through meshing of an inner gear ring and an inner gear ring support or a rear differential shell gear cover.

Description

Technical Field

[0001] The present invention relates to the technical field of power systems, and in particular to a novel power system structure for an electric drive axle. Background Art

[0002] With the rapid development of new energy vehicle technology, the market demand for new energy commercial vehicles continues to increase. In the power system of new energy commercial vehicles, the axle power system is a key component to achieve vehicle drive. However, the existing axle power system structure of new energy commercial vehicles has some technical limitations and needs to be improved urgently.

[0003] At present, the power system structure of new energy commercial vehicle axles is mainly divided into two categories: 1. Central direct drive structure: This structure replaces the traditional engine and transmission with an electric motor, and directly drives the wheels through the output power of the motor. Although this structure is simple, its power transmission efficiency and reliability have certain limitations under complex working conditions of the vehicle. 2. Wheel-side direct drive structure: The wheel-side direct drive structure includes two forms: single-motor axle and dual-motor axle. Its power system is usually composed of a reducer mechanism, a differential structure and a speed change mechanism, and these three parts are usually separated independently.

[0004] Although the above structure can meet the basic driving requirements of the vehicle, it has the following problems in practical application:

[0005] 1. Large size and heavy weight: Since the reducer, differential and transmission mechanism are designed separately, the size and weight of the entire power system are large, which increases the vehicle's energy consumption and operating costs.

[0006] 2. Complex structure: The connection and coordination between the components are relatively complicated, which increases the assembly difficulty and maintenance cost of the system.

[0007] 3. Poor reliability: Independent reducers, differentials and speed change mechanisms are prone to failure during long-term operation, reducing the reliability of the system.

[0008] In view of the problems in the related art, the present invention provides a new power system structure for an electric drive axle. Summary of the invention

[0009] The purpose of the present invention is to provide a new power system structure for an electric drive axle in view of the defects of the prior art.

[0010] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0011] A new power system structure for an electric drive axle, comprising a reducer system, a differential system and a speed change system, wherein the reducer system, the differential system and the speed change system are integrated into one;

[0012] The reducer system includes a driving wheel, a driven wheel, and a driven wheel output shaft;

[0013] The driving wheel is meshed with the motor shaft through a spline;

[0014] The driven wheel meshes with the driving wheel;

[0015] The driven wheel output shaft is fixedly arranged in the driven wheel, and the driven wheel output shaft contains an internal spline;

[0016] The differential system includes a sun gear, planetary gears, a differential housing, an inner gear ring, an inner gear ring bracket, a rear differential housing gear cover, a differential planetary gear, a differential half-shaft gear, and a differential bracket; the sun gear, planetary gears, differential housing, and inner gear ring constitute a planetary gear train, and the differential housing serves as a planet carrier;

[0017] The sun gear meshes with the internal spline of the output shaft of the driven gear;

[0018] The planetary gear is arranged outside the sun gear and meshes with the sun gear;

[0019] An inner gear ring is sleeved outside the planetary gear and meshes with the planetary gear;

[0020] The differential housing is connected to the differential support and the rear differential housing gear cover respectively, and the differential support and the rear differential housing gear cover are respectively arranged on both sides of the inner gear ring;

[0021] An inner ring gear bracket connected to a differential bracket;

[0022] The differential planetary gear meshes with the differential side shaft gears;

[0023] The speed change system realizes the speed change function through the meshing of the inner gear ring and the inner gear ring bracket or the rear differential case gear cover.

[0024] Furthermore, the transmission system also includes a shift cylinder and a shift fork, wherein the shift cylinder is connected to the shift fork, and the end of the shift fork is embedded in the inner gear ring to control the left and right movement of the inner gear ring to achieve switching between low gear and high gear.

[0025] Furthermore, a copper block is provided on the shift fork, a groove matching the copper block is provided on the surface of the inner gear ring, and the shift fork cooperates with the groove of the inner gear ring through the copper block.

[0026] Furthermore, the differential housing includes a front housing and a rear housing, the front housing and the rear housing are connected by bolts, the front housing is interference fit with the bearing in the differential bracket, and the rear housing is fixedly connected to the rear differential housing gear cover by bolts.

[0027] Furthermore, the sun gear limits the axial displacement of the sun gear through a retaining spring and the output shaft of the driven gear.

[0028] Furthermore, two ends of the planetary gear shaft are respectively fixed on the differential case and the rear differential case gear cover.

[0029] Furthermore, the differential half-shaft gear is connected to the differential housing, and the differential planetary gear is fixed to the differential housing via the differential planetary gear shaft.

[0030] Furthermore, the inner gear ring is meshed with the inner gear ring bracket or the rear differential case gear cover through a shift fork.

[0031] Furthermore, the power system also includes a motor front end cover and a gear frame, and the motor front end cover is fixedly connected to the gear frame through bolts and locating pins.

[0032] Furthermore, the driving wheel and the driven wheel are fixedly connected to the front end cover of the motor and the gear frame through bearings respectively.

[0033] Compared with the prior art, the present invention proposes a new power system structure for an electric drive axle, which aims to organically combine the reducer system, the differential system and the transmission system through an integrated design, thereby greatly reducing the volume and weight of the power system, simplifying the structure, improving reliability, and reducing manufacturing and maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of a new power system structure for an electric drive axle provided in an embodiment;

[0035] Among them, 1. motor; 2. gear rack; 3. driving wheel; 4. driven wheel; 5. driven wheel output shaft; 6. sun gear; 7. planetary gear; 8. planetary gear shaft; 9. differential case; 10. inner ring gear; 11. inner ring gear bracket; 12. rear differential case gear cover; 13. differential planetary gear; 14. differential half-shaft gear; 15. differential bracket; 16. shift cylinder; 17. shift fork; 18. differential planetary gear shaft. DETAILED DESCRIPTION

[0036] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0037] The purpose of the present invention is to provide a new power system structure for an electric drive axle in view of the defects of the prior art.

[0038] Example

[0039] This embodiment provides a new power system structure for an electric drive bridge, such as Figure 1 As shown, it includes a motor 1, a gear rack 2, a reducer system, a differential system and a speed change system, wherein the reducer system, the differential system and the speed change system are integrated into one.

[0040] The gear rack 2 is a frame structure with sufficient strength and rigidity to withstand the torque and force during the transmission process. The gear rack is provided with a plurality of holes and slots for installing the main reducer mechanism.

[0041] The gear frame 2 is connected to the front cover of the motor 1 by bolts and positioning pins to ensure that the relative positions of the two are fixed. There are four bearing holes on the motor 1 and the gear frame 2, which are used to install the first bearing, the second bearing, the third bearing, and the fourth bearing, respectively, to support the main reducer mechanism and ensure its normal operation.

[0042] It should be noted that the present embodiment does not provide a detailed description of the motor 1 and the gear rack 2, and reference may be made to the existing structure.

[0043] The reducer system includes a driving wheel 3, a driven wheel 4, and a driven wheel output shaft 5.

[0044] The driving wheel 3 is a cylindrical gear with external teeth; the driving wheel 3 is installed at the output end of the motor 1, and is fixedly connected to the front end cover and the gear frame 2 of the motor 1 through the first bearing and the second bearing. The matching mode of the driving wheel 3 and the bearing is an interference fit.

[0045] The driven wheel 4 is a cylindrical gear with external teeth, and a matching hole with a diameter of 93 mm is opened inside; the driven wheel 4 is installed on the front end cover of the motor 1, and is fixedly connected to the front end cover of the motor 1 and the gear frame 2 through the third bearing and the fourth bearing, and the matching mode of the driven wheel 4 and the bearing is an interference fit; the external teeth of the driven wheel 4 mesh with the external teeth of the driving wheel 3, and the driven wheel 4 and the driving wheel 3 are arranged opposite to each other, located opposite to the driving wheel 3, and a certain center distance is maintained between the two to ensure that the gears can mesh correctly.

[0046] The driven wheel output shaft 5 is a hollow cylindrical shaft with internal splines; the diameter of the driven wheel output shaft 5 is the same as the inner diameter of the driven wheel 4, so that the driven wheel output shaft 5 is arranged in the driven wheel 4 through an interference fit and is further fixed by bolts.

[0047] The differential system includes a sun gear 6, planetary gears 7, a planetary gear shaft 8, a differential case 9, an inner ring gear 10, an inner ring gear bracket 11, a rear differential case gear cover 12, differential planetary gears 13, differential half-shaft gears 14, a differential bracket 15, and a differential planetary gear shaft 18.

[0048] The differential housing 9 is the main housing component of the differential system, and is used to accommodate and support components such as the planetary gears 7, planetary gear shafts 8, differential planetary gears 13, differential half-shaft gears 14, and differential planetary gear shafts 18 inside the differential.

[0049] The differential housing 9 is a part of the planet carrier and plays the dual functions of the planet carrier and the differential housing. The differential housing 9 is a split structure, divided into a front housing and a rear housing (not marked in the figure), which are connected by bolts. The front housing is interference fit with the bearing in the differential support 15, and the rear housing is fixedly connected with the rear differential housing gear cover 12 by bolts. There are several (such as 3, the same number as the number of planetary gear shafts) holes spaced 120 degrees on the differential housing 9, which are used to fix one end of the planetary gear shaft 8.

[0050] The rear differential case gear cover 12 is in the shape of a disc with fixed teeth or a positioning structure. It is the rear cover of the differential case 9 and is fixed to the differential case 9 by bolts. It is mainly used for speed change and supporting the planetary gear shaft, and together with the differential case 9, it forms a complete differential housing. The rear differential case gear cover 12 can be meshed with or fixedly connected to the inner gear ring 10. There are also several (such as 3, the same number as the number of planetary gear shafts) holes spaced 120 degrees on the rear differential case gear cover 12, which are used to fix the other end of the planetary gear shaft 8.

[0051] The differential support 15 is arranged outside the differential housing 9 and is fixedly connected to the differential housing 9 and the external bridge housing respectively, and is used to install the differential housing 9 on the external bridge housing to play a supporting and positioning role. The differential support 15 is fixed to the differential housing 9 by an interference fit through a bearing, and the differential support 15 is fixedly connected to the external bridge housing by bolts.

[0052] The sun gear 6 is a cylindrical gear with external teeth; one end of the sun gear 6 close to the driven wheel output shaft 5 is an external spline, and the external spline of the sun gear 6 cooperates with the internal spline of the driven wheel output shaft 5 to receive the power transmitted by the driven wheel 4.

[0053] In this embodiment, in order to prevent the sun gear 6 from axially moving, the sun gear 6 is matched with the driven gear output shaft 5 through a retaining spring, thereby limiting the axial movement of the sun gear 6 .

[0054] The shape of the retaining spring groove is usually an annular groove. The retaining spring is clamped on the sun gear 6 and contacts the driven wheel output shaft 5.

[0055] The planetary gear 7 is a cylindrical gear with external teeth, and there are multiple planetary gears 7 (such as 3 or 4). The multiple planetary gears 7 are installed on the differential housing 9 through the planetary gear shaft 8 inside them, and the multiple planetary gears 7 are arranged around the sun gear 6 near the other end and meshed with the sun gear 6 so that the planetary gears 7 are driven to rotate when the sun gear 6 rotates.

[0056] The two ends of the planetary axle 8 are fixedly mounted in holes on the differential case 9 and the rear differential case gear cover 12 , respectively, and the planetary gear 7 is sleeved on the planetary axle 8 .

[0057] The inner gear ring 10 is a circular ring structure with inner teeth and grooves on the outside. The inner gear ring 10 is sleeved around the outer peripheries of the plurality of planetary gears 7 and meshes with the planetary gears 7 .

[0058] The inner ring gear bracket 11 is in the shape of a disc with fixed teeth or a positioning structure and has bolt holes; the inner ring gear bracket 11 is located at the periphery of the differential housing 9 and is fixedly connected to the differential bracket 11 by bolts; the inner ring gear bracket 11 can mesh with the inner ring gear 10, and the inner ring gear 10 and the inner ring gear bracket 11 are engaged to switch to a low gear; wherein, the inner ring gear 10 is always meshed with the planetary gear 7 regardless of neutral, low gear or high gear.

[0059] The differential planetary gear 13 is a conical spur gear with external teeth, which is installed in the differential case 9 through the differential planetary gear shaft 18 and meshes with the differential side shaft gear 14 .

[0060] The differential axle gear 14 is a conical spur gear with external teeth, which meshes with the differential planetary gear 13, and the internal splines of the differential axle gear 14 cooperate with the external splines of the axle shaft to transmit power to the axle shaft to rotate the wheels.

[0061] The transmission system is composed of an inner gear ring 10, an inner gear ring bracket 11, a rear differential case gear cover 12, a planetary gear 7, a shift cylinder 16, and a shift fork 17;

[0062] The shift cylinder 16 is fixed on the external bridge housing rear cover and is used to drive the shift fork 17 .

[0063] The shift fork 17 is in the shape of an elongated strip, with two copper blocks at the end, which are embedded in the groove of the inner gear ring 10, and the position of the inner gear ring 10 is switched by moving left and right.

[0064] A new power system structure for an electric drive axle in this embodiment has a power transmission path as follows:

[0065] In the initial state, the inner ring gear 10 is in a transition state, and is neither meshed with the inner ring gear support 11 nor meshed with the rear differential case gear cover 12 .

[0066] When the power system is running at low speed:

[0067] When the piston rod of the shift cylinder 16 drives the shift fork 17 to move right, the shift fork 17 pushes the inner gear ring 10 to move right through the copper block at its end, and the inner gear ring 10 meshes with the fixed teeth on the inner gear ring bracket 11, and the inner gear ring 10 is fixed. At this time, there is relative motion between the planetary gear 7 and the inner gear ring 10, achieving a larger reduction ratio, a lower output speed, and a larger torque.

[0068] The power is transmitted from the output end of the motor 1 to the main reducer mechanism. After the driving wheel 3 in the main reducer mechanism receives the power transmitted by the motor 1, the power is transmitted from the driving wheel 3 to the driven wheel 4. The driven wheel 4 transmits the power to the planetary reduction mechanism through the driven wheel output shaft 5. The sun gear 6 in the planetary reduction mechanism receives the power transmitted by the driven wheel output shaft 5. The power is transmitted from the sun gear 6 to the planetary gear 7. The planetary gear 7 rolls between the inner ring gear 10 and the sun gear 6 to achieve deceleration. At this time, the power is transmitted from the planetary gear 7 to the planetary gear shaft 8, and the power is transmitted to the differential case 9 through the planetary gear shaft 8.

[0069] When the power system is running at high speed:

[0070] The piston rod of the shift cylinder 16 moves to the left, driving the shift fork 17 to move to the left. At this time, the copper block at the end of the shift fork 17 is always embedded in the groove of the inner ring gear 10, and the inner ring gear 10 is pushed to move to the left by the copper block. As the inner ring gear 10 moves to the left, the inner ring gear 10 gradually breaks away from the meshing relationship with the inner ring gear bracket 11. When the inner ring gear 10 moves to the left to the specified position, the inner ring gear 10 meshes with the teeth on the rear differential case gear cover 12. At this time, the inner ring gear 10 rotates synchronously with the differential case 9, and there is no relative movement between the planetary gear 7 and the inner ring gear 10, achieving a higher transmission efficiency, a higher output speed, and a relatively small torque.

[0071] The power is transmitted from the output end of the motor 1 to the main reducer mechanism. After the driving wheel 3 in the main reducer mechanism receives the power transmitted by the motor 1, the power is transmitted from the driving wheel 3 to the driven wheel 4. The driven wheel 4 transmits the power to the planetary reduction mechanism through the driven wheel output shaft 5. The sun gear 6 in the planetary reduction mechanism receives the power transmitted by the driven wheel output shaft 5. The power is transmitted from the sun gear 6 to the planetary gear 7. There is no relative movement between the planetary gear 7 and the inner ring gear 10. At this time, the power is transmitted from the planetary gear 7 to the planetary gear shaft 8, and the power is transmitted to the differential case 9 through the planetary gear shaft 8.

[0072] When it is determined whether to run at high speed or low speed, the power is transmitted from the differential case 9 to the differential planetary gear 13, the differential planetary gear 13 distributes the power to the differential half-shaft gear 14, the differential half-shaft gear 14 transmits the power to the half-shaft, and finally to the outer wheel.

[0073] The power system proposed in this embodiment realizes efficient, compact and reliable operation of the power system by integrating the reducer system, differential system and transmission system. Compared with the prior art, the present invention has the following significant beneficial effects:

[0074] 1. Significantly reduce the size and weight of the power system

[0075] By integrating the reducer, differential and transmission system into one, the connection structure and space occupied by traditional independent components are reduced. This integrated design greatly reduces the volume and weight of the entire power system, thereby improving the vehicle's energy efficiency and load-carrying capacity.

[0076] 2. Improve the reliability of the power system

[0077] The integrated design reduces the number of components and connection points, reducing the risk of failure caused by complex structures. At the same time, the design of the differential half-shaft gear axis and the half-shaft concentricity further improves the stability and reliability of power transmission, reduces vibration and noise, and extends the service life of the system.

[0078] 3. Reduce manufacturing and maintenance costs

[0079] Due to the simplification of system structure and the reduction of the number of parts, the manufacturing process is more efficient and the production cost is significantly reduced. In addition, the integrated design makes maintenance more convenient, reduces maintenance time and maintenance costs, and improves the economy of the vehicle.

[0080] 4. Optimize power transmission efficiency

[0081] The power transmission path is reasonably designed, and efficient power transmission is achieved through the integration of the planetary gear train and the differential. The speed change function design of the inner ring gear further optimizes the transmission ratio of the power system and improves the performance of the vehicle under different working conditions.

[0082] 5. Enhance the adaptability and flexibility of the system

[0083] The inner ring gear achieves the speed change function by meshing with the planetary gear, the inner ring gear bracket or the rear differential case gear cover. This design not only realizes the switching between low gear and high gear, but also enhances the adaptability of the power system to different driving conditions and improves the flexibility and economy of the vehicle.

[0084] 6. Simplify assembly and maintenance process

[0085] The integrated design makes the power system assembly easier, reducing assembly time and labor costs. At the same time, the simplification of the system also makes maintenance easier, reducing maintenance difficulties caused by complex structures.

[0086] 7. Improve the overall performance of the vehicle

[0087] By optimizing the structure and function of the power system, the present invention not only improves the power transmission efficiency, but also reduces the energy consumption and operating costs of the vehicle. This high-performance power system structure provides strong support for the widespread application of new energy commercial vehicles.

[0088] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A new power system structure for an electric drive axle, characterized in that: It includes a speed reducer system, a differential system and a speed change system, wherein the speed reducer system, the differential system and the speed change system are integrated into one; The reducer system includes a driving wheel, a driven wheel, and a driven wheel output shaft; The driving wheel is meshed with the motor shaft through a spline; The driven wheel meshes with the driving wheel; The driven wheel output shaft is fixedly arranged in the driven wheel, and the driven wheel output shaft contains an internal spline; The differential system includes a sun gear, planetary gears, a differential housing, an inner gear ring, an inner gear ring bracket, a rear differential housing gear cover, a differential planetary gear, a differential half-shaft gear, and a differential bracket; the sun gear, planetary gears, differential housing, and inner gear ring constitute a planetary gear train, and the differential housing serves as a planet carrier; The sun gear meshes with the internal spline of the output shaft of the driven gear; The planetary gear is arranged outside the sun gear and meshes with the sun gear; An inner gear ring is sleeved outside the planetary gear and meshes with the planetary gear; The differential housing is connected to the differential support and the rear differential housing gear cover respectively, and the differential support and the rear differential housing gear cover are respectively arranged on both sides of the inner gear ring; An inner ring gear bracket connected to a differential bracket; The differential planetary gear meshes with the differential side shaft gears; The speed change system realizes the speed change function through the meshing of the inner gear ring and the inner gear ring bracket or the rear differential case gear cover.

2. A new power system structure for an electric drive axle according to claim 1, characterized in that: The transmission system also includes a shift cylinder and a shift fork. The shift cylinder is connected to the shift fork. The end of the shift fork is embedded in the inner gear ring to control the left and right movement of the inner gear ring to achieve switching between low gear and high gear.

3. A new power system structure for an electric drive axle according to claim 2, characterized in that: The shift fork is provided with a copper block, the surface of the inner gear ring is provided with a groove matched with the copper block, and the shift fork is matched with the groove of the inner gear ring through the copper block.

4. A new power system structure for an electric drive axle according to claim 1, characterized in that: The differential housing comprises a front housing and a rear housing, the front housing and the rear housing are connected by bolts, the front housing is interference fit with the bearing in the differential bracket, and the rear housing is fixedly connected with the rear differential housing gear cover by bolts.

5. A new power system structure for an electric drive axle according to claim 1, characterized in that: The sun gear is limited in its axial displacement by a retaining spring and a driven wheel output shaft.

6. A new power system structure for an electric drive axle according to claim 1, characterized in that: The two ends of the planetary gear shaft are respectively fixed on the differential housing and the rear differential case gear cover.

7. A new power system structure for an electric drive axle according to claim 1, characterized in that: The differential half-shaft gear is connected to the differential housing, and the differential planetary gear is fixed on the differential housing through the differential planetary gear shaft.

8. A new power system structure for an electric drive axle according to claim 1, characterized in that: The inner gear ring is meshed with the inner gear ring support or the rear differential case gear cover through a shift fork.

9. A new power system structure for an electric drive axle according to claim 1, characterized in that: The power system also includes a motor front end cover and a gear frame, and the motor front end cover is fixedly connected to the gear frame through bolts and positioning pins.

10. A new power system structure for an electric drive axle according to claim 9, characterized in that: The driving wheel and the driven wheel are fixedly connected to the front end cover of the motor and the gear frame through bearings respectively.

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