Two-gear heavy truck electric drive axle

Abstract

A two-gear heavy truck electric drive axle comprises a drive motor and a main shaft in transmission connection with the drive motor and further comprises a differential mechanism, the differential mechanism is in transmission connection with an output half shaft, the main shaft and the differential mechanism are in transmission connection through a gear shifting mechanism, and the gear shifting mechanism at least comprises a first-gear transmission assembly and a second-gear transmission assembly. The second-gear transmission assembly is in transmission connection with the differential mechanism, and the first-gear transmission assembly is in transmission connection with the differential mechanism through the first speed reducing mechanism. The invention provides a two-gear heavy truck electric drive axle. The high-speed gear and the low-speed gear are both connected with the differential mechanism, the high-speed gear is directly connected with the differential mechanism, high transmission efficiency is achieved, and the high-speed long-time running endurance requirement can be met; the low-speed gear is in transmission connection with the differential mechanism through the first speed reducing mechanism, and large-torque output is achieved. Therefore, efficiency and large-torque output performance are both considered, good economical efficiency is achieved, meanwhile, direct connection of an intermediate shaft system and a differential mechanism is omitted, and the space layout optimization effect is obvious.

Description

Technical Field

[0001] The present invention relates to the field of electric drive systems for engineering machinery, and in particular to a two-speed electric drive axle for heavy trucks. Background Art

[0002] The drive system of heavy trucks currently includes traditional internal combustion engine drives and the pure electric drive system that is gradually becoming popular. Compared with traditional fuel drive systems, pure electric drive systems have shown significant advantages in environmental protection, economy, safety, and efficiency, and are important equipment for promoting green mines and green development concepts. In the application conditions of some heavy truck electric drive systems, it is necessary to take into account both large torque output and high-speed and long-term operation, so it is necessary to take into account both economy and power performance. And in the layout of the transmission system, the limited space is used as much as possible to optimize the space occupancy problem.

[0003] Through searching, relevant technical documents of heavy-duty truck electric drive axles have been disclosed in the prior art. For example, the invention patent publication document with the publication number "CN119078493A" and the name "An electric drive axle reducer" is disclosed. An electric drive axle reducer is disclosed. The electric drive axle reducer includes: a motor, a differential, a power take-off and a shaft system; the first intermediate shaft and the second intermediate shaft in the intermediate shaft group of the shaft system are arranged on the same side of the central shaft in the shaft system, and the second intermediate shaft and the third intermediate shaft in the intermediate shaft group are arranged on both sides of the central shaft; the motor and the power take-off are respectively arranged on both sides of the central shaft; the central shaft is idling on the first output half shaft in the power output shaft group of the shaft system, and is connected to the differential through the second intermediate shaft and the third intermediate shaft; the differential is respectively connected to the first output half shaft and the second output half shaft in the power output shaft group; the power take-off is connected to the central shaft through the power take-off output shaft of the shaft system. In the technical solution disclosed in the reference document, the motor, shaft system and power take-off are arranged on both sides of the center line of the power output shaft group, which solves the problem of low load-bearing capacity of the electric drive axle due to poor overall force of the electric drive axle after the reducer is integrated into the axle housing in the prior art. However, both gears are connected through the shaft system and differential transmission, with low transmission efficiency and excessive space occupation.

[0004] For example, the utility model patent authorization announcement document with the publication number "CN218777413U" and the name "Electric drive axle structure driven by a single motor". An electric drive axle structure driven by a single motor is provided, including: an input driving gear, driven by a single motor; a sun gear shaft, fixedly connected to a planetary gear row and slidably connected to a first shifter; an intermediate shaft, relatively rotatably sleeved outside the sun gear shaft, and fixedly connected to an input passive gear and a first shift passive gear, the input passive gear is driven by the input driving gear; a second shift passive gear, relatively rotatably sleeved outside the sun gear shaft; a parallel shaft, fixedly connected to a first shift driving gear and a second shift driving gear, the first shift passive gear is driven by the first shift driving gear, and the second shift passive gear is driven by the second shift driving gear; a second shifter, arranged on the second shift passive gear or the planetary carrier of the planetary gear row and selectively engaging or disconnecting the second shift passive gear and the planetary carrier; and a differential. This comparative document also has the technical problem of low transmission efficiency of the above-mentioned comparative document. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a two-speed heavy-duty truck electric drive axle, comprising a drive motor and a main shaft transmission-connected thereto, and also comprising a differential, wherein the differential and an output half-shaft are transmission-connected, wherein the main shaft and the differential are transmission-connected via a shifting mechanism, wherein the shifting mechanism comprises at least a first-speed transmission assembly and a second-speed transmission assembly, wherein the second-speed transmission assembly and the differential are transmission-connected, and the first-speed transmission assembly and the differential are transmission-connected via a first reduction mechanism.

[0006] Furthermore, the shift mechanism includes a shift gear sleeve connected to one end of the main shaft, and the second gear transmission assembly includes a second gear gear seat connected to the differential housing.

[0007] Furthermore, the first gear transmission assembly includes a first gear gear and a second parallel reduction unit distributed on both sides of the differential, one end of the second parallel reduction unit is meshed with the first gear gear, and the other end is meshed with the first gear convergence gear connected to the differential.

[0008] Furthermore, the first gear is sleeved on the differential housing.

[0009] Furthermore, the housing of the differential includes a front housing and a rear housing that are butt-jointed, the main shaft is a hollow shaft, one end of the front housing is embedded in one end of the main shaft and is connected through a first tapered bearing.

[0010] Furthermore, the first gear is sleeved on the front housing of the differential.

[0011] Furthermore, the first-gear convergent gear and the front housing of the differential are connected via a spline.

[0012] Furthermore, an auxiliary supporting rolling bearing is sleeved on the second gear seat, and the shifting gear sleeve can be in contact with the rolling bearing.

[0013] Furthermore, the drive motor is transmission-connected to the main shaft via a first parallel reduction unit.

[0014] Furthermore, the second parallel reduction unit includes a first-gear split intermediate shaft distributed on both sides of the differential, and the first parallel reduction unit includes an intermediate shaft distributed on one side of the main shaft, and the intermediate shaft and the first-gear split intermediate shaft are staggered along the axial direction of the differential.

[0015] Compared with the prior art, the technical solution of the present application has the following beneficial effects: the two-speed heavy-duty truck electric drive axle proposed in the present invention. Both high and low speed gears are connected to the differential, wherein the high speed gear is directly connected to the differential, and has a higher transmission efficiency, which can meet the requirements of high-speed and long-term operation and endurance; the low speed gear utilizes the first reduction mechanism and the differential transmission connection to achieve high torque output. Therefore, both efficiency and high torque output performance are taken into account, and it has good economy, while the intermediate shaft system and the direct connection of the differential are omitted, and the spatial layout optimization effect is more obvious. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 : Transmission principle diagram of two-speed heavy-duty truck electric drive axle; Figure 2 : Structural principle diagram of two-speed heavy-duty truck electric drive axle; Figure 3 : Schematic diagram of the shaft distribution structure of the two-speed heavy-duty truck electric drive axle; Figure 4 : Schematic diagram of the shaft distribution structure of a two-speed heavy-duty truck electric drive axle. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] like Figure 1 and Figure 2 As shown: a two-speed heavy-duty truck electric drive axle, including a drive motor 1 and a main shaft 2 transmission-connected thereto, and also including a differential 3, the differential 3 and an output half shaft 4 are transmission-connected, the main shaft 2 and the differential 3 are transmission-connected via a shifting mechanism 5, the shifting mechanism 5 includes at least a first-speed transmission assembly 51 and a second-speed transmission assembly 52, the second-speed transmission assembly 52 is transmission-connected to the differential 3, and the first-speed transmission assembly 51 is transmission-connected to the differential 3 via a first reduction mechanism 6.

[0019] In this embodiment, when the gear is in high gear, the power is transmitted to the main shaft 2 through the drive motor 1 and then directly connected to the housing of the differential 3, and the output half shaft 4 is driven by the differential 3. At this time, the vehicle can run efficiently for a long time in high gear. When the gear is in low gear, the power is transmitted to the housing of the differential 3 through the first reduction mechanism 6, thereby achieving deceleration and torque increase to meet the demand for high torque output.

[0020] In a more preferred embodiment, the shift mechanism 5 includes a shift gear sleeve 53 connected to one end of the main shaft 2, and the second gear transmission assembly 52 includes a second gear tooth seat 521 connected to the housing of the differential 3. When switching to the second gear high speed gear, the shift gear sleeve 53 slides along the main shaft 2 until it is engaged with the second gear tooth seat 521. Since the second gear tooth seat 521 and the housing of the differential 3 are splined or welded, the second gear tooth seat 521 can drive the housing of the differential 3 to rotate and then drive the output half shaft 4.

[0021] In a more preferred embodiment, the first gear transmission assembly 51 includes a first gear gear 511, and also includes a second parallel reduction unit distributed on both sides of the differential 3, one end of the second parallel reduction unit is meshed with the first gear gear 511, and the other end is meshed with the first gear converging gear 512 connected to the differential 3. The second parallel reduction unit actually includes two sets of parallel reduction mechanisms. Each set of parallel reduction mechanisms includes a first gear split intermediate shaft 513, and the first gear split intermediate shaft 513 is respectively connected to a first gear driving gear 514 and a first gear driven gear 515, the first gear driving gear 514 is meshed with the first gear gear 511, and the first gear driven gear 515 is meshed with the first gear converging gear 512. When the gear is in the first gear low speed gear, the power main shaft 2 passes through the shift gear sleeve 53 to the first gear gear 511, and then passes through the first gear driving gear 514 and the first gear driven gear 515, and finally the first gear converging gear 512 to converge the torque to the differential 3 housing. The second parallel reduction unit under this design is merged by the double first gear split intermediate shaft 513, which can make the first gear driving gear 514 and the first gear merge gear 512 have a smaller volume, so as to make full use of the free space around the differential 3 and the main shaft 2. The transmission structure under this combination can achieve the requirements of high strength and high rigidity of the transmission system when the first gear has a large torque output, and meet the requirements of high efficiency in the second gear.

[0022] In a more preferred embodiment, the first gear 511 is sleeved on the housing of the differential 3. In this embodiment, a groove is provided on the housing of the differential 3, and a bearing is embedded in the groove. The first gear 511 is directly sleeved on the housing of the differential 3 to fully utilize its structural space and strength.

[0023] In a more preferred embodiment, the housing of the differential 3 includes a front housing 31 and a rear housing 32 that are butted together. The main shaft 2 is a hollow shaft, and one end of the front housing 31 is embedded in one end of the main shaft 2 and connected through the first tapered bearing 21. In this embodiment, the front housing 31 and the rear housing 32 are butted together through flanges, and the connecting end of the main shaft 2 and the front housing 31 is designed with a large opening to be embedded in the first tapered bearing 21, and the output half shaft 4 can pass through the main shaft 2. Relative to one end of the first tapered bearing 21, the rear housing 32 is supported and connected by the second tapered bearing 22. The tapered bearings at both ends of the main shaft 2 and the housing of the differential 3 are used to bear the main component forces of the system, ensuring that the transmission system has a high structural strength and saving space as much as possible.

[0024] In a more preferred embodiment, the first gear 511 is sleeved on the front housing 31 of the differential 3. In this embodiment, the front housing 31 of the differential 3 is redesigned as an elongated structure, which needs to sleeve the first gear 511 and connect the second gear gear holder 521, that is, the space and structural strength of the front housing 31 are fully utilized.

[0025] In a more preferred embodiment, the first-gear converging gear 512 and the front housing 31 of the differential 3 are connected by splines. Under the design, when the first-gear converging gear 512 is assembled with the second parallel reduction unit, it is inevitable to adjust the gap between the first-gear converging gear 512 and the front housing 31 of the differential 3 due to the progress of processing or assembly. Therefore, the spline connection can reserve a certain adjustment gap, which is convenient for assembling the gears and improving the eccentric load adjustment ability of the converging gear.

[0026] In a more preferred embodiment, the second gear tooth seat 521 is sleeved with an auxiliary support rolling bearing 522, and the shift gear sleeve 53 can contact the rolling bearing 522. When the shift mechanism 5 is shifting, the shift gear sleeve 53 slides along the main shaft 2. When it is necessary to switch to the first gear and low speed gear, the shift gear sleeve 53 needs to slide to the first gear gear 511. The axial sliding distance is relatively long, which may cause the shift gear sleeve 53 to axially deviate, resulting in a stuck shift or failure to shift gears. Therefore, an auxiliary support rolling bearing 522 is sleeved on the second gear tooth seat 521. When the shift gear sleeve 53 slides through the second gear tooth seat 521, the auxiliary support rolling bearing 522 can be used to axially support it, thereby improving the success rate of switching to the first gear and low speed gear, while strengthening the system rigidity and ensuring the rotation accuracy of the main shaft 2.

[0027] In a more preferred embodiment, the drive motor 1 is connected to the main shaft 2 through a first parallel reduction unit. The power is transmitted to the main shaft 2 through the first parallel reduction unit to achieve a first-stage reduction and torque increase. The first parallel reduction unit includes an intermediate shaft 11 distributed on one side of the main shaft 2, and the two ends of the intermediate shaft 11 are connected to a first-stage driven gear 111 and a first-stage driving gear 112, and one end of the drive motor 1 is connected to the input shaft 12. The first-stage driven gear 111 is meshed with the input shaft 12, and the first-stage driving gear 112 is meshed with the main reduction gear 23 on the main shaft 2.

[0028] In a more preferred embodiment, the second parallel reduction unit includes a first-gear split intermediate shaft 513 distributed on both sides of the differential 3, and the first parallel reduction unit includes an intermediate shaft 11 distributed on one side of the main shaft 2, and the intermediate shaft 11 and the first-gear split intermediate shaft 513 are staggered along the axial direction of the differential 3. For details, see Figure 3 and Figure 4 The two first-gear split intermediate shafts 513, the intermediate shaft 11, and the input shaft 12 are all staggered, which is beneficial to the arrangement and space utilization of the electric drive axle assembly, and there is sufficient space for assembly connection between the drive motor 1 and the input shaft 12.

[0029] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0030] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A two-speed heavy-duty truck electric drive axle, characterized in that: The invention comprises a driving motor (1) and a main shaft (2) drivingly connected thereto, and also comprises a differential (3), wherein the differential (3) is drivingly connected to an output half shaft (4), wherein the main shaft (2) and the differential (3) are drivingly connected via a shifting mechanism (5), wherein the shifting mechanism (5) comprises at least a first gear transmission assembly (51) and a second gear transmission assembly (52), wherein the second gear transmission assembly (52) is drivingly connected to the differential (3), and the first gear transmission assembly (51) is drivingly connected to the differential (3) via a first reduction mechanism (6).

2. The two-speed heavy-duty truck electric drive axle according to claim 1, characterized in that: The shift mechanism (5) comprises a shift gear sleeve (53) connected to one end of the main shaft (2), and the second gear transmission assembly (52) comprises a second gear gear seat (521) connected to the housing of the differential (3).

3. The two-speed heavy-duty truck electric drive axle according to claim 1, characterized in that: The first gear transmission assembly (51) comprises a first gear gear (511), and also comprises a second parallel reduction unit distributed on both sides of the differential (3), one end of the second parallel reduction unit being meshed with the first gear gear (511), and the other end being meshed with the first gear convergence gear (512) connected to the differential (3).

4. The two-speed heavy-duty truck electric drive axle as claimed in claim 3, characterized in that: The first gear (511) is sleeved on a housing of the differential (3).

5. The two-speed heavy-duty truck electric drive axle as claimed in claim 4, characterized in that: The housing of the differential (3) comprises a front housing (31) and a rear housing (32) that are butt-jointed, the main shaft (2) is a hollow shaft, one end of the front housing (31) is embedded in one end of the main shaft (2) and is connected via a first tapered bearing (21).

6. The two-speed heavy-duty truck electric drive axle as claimed in claim 5, characterized in that: The first gear (511) is sleeved on the front housing (31) of the differential (3).

7. The two-speed heavy-duty truck electric drive axle as claimed in claim 6, characterized in that: The first-gear convergent gear (512) and the front housing (31) of the differential (3) are connected via a spline.

8. The two-speed heavy-duty truck electric drive axle as claimed in claim 2, characterized in that: The second gear seat (521) is sleeved with an auxiliary support rolling bearing (522), and the shifting gear sleeve (53) can be in contact with the rolling bearing (522).

9. The two-speed heavy-duty truck electric drive axle as claimed in claim 3, characterized in that: The drive motor (1) is transmission-connected to the main shaft (2) via a first parallel reduction unit.

10. The two-speed heavy-duty truck electric drive axle as claimed in claim 9, characterized in that: The second parallel reduction unit comprises a first-gear split intermediate shaft (513) distributed on both sides of the differential (3), and the first parallel reduction unit comprises an intermediate shaft (11) distributed on one side of the main shaft (2), wherein the intermediate shaft (11) and the first-gear split intermediate shaft (513) are staggered along the axial direction of the differential (3).

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