Commercial vehicle electric drive axle with idle wheel structure

Abstract

The invention relates to the technical field of electric drive axles, and discloses a commercial vehicle electric drive axle with an idle wheel structure. A drive motor is connected with an input shaft, and the input shaft is provided with a first-stage driving gear; an idle gear and a secondary driving gear are arranged on the first intermediate shaft; the output end of the power takeoff is connected with a power takeoff driven wheel through an output shaft; a left half shaft, a right half shaft and a four-stage driven gear are arranged on the differential mechanism assembly; the hollow center shaft is arranged on the right half shaft in a sleeving mode, a third-level driving gear is arranged on the hollow center shaft, the second-gear gear and the first-gear gear are arranged on the hollow center shaft in an empty sleeving mode, and a gear shifting gear hub and a gear shifting gear sleeve are further arranged on the hollow center shaft. And a fourth-stage driving gear and a third-stage driven gear are arranged on the second intermediate shaft. The idle gear is adopted, the four-stage speed reduction structure is adopted under the first-gear working condition, the three-stage speed reduction structure is adopted under the second-gear working condition, a power takeoff gear and part of bearings can be omitted, the transmission chain structure is optimized, and the whole transmission chain is light.

Description

Technical Field

[0001] The present invention relates to the technical field of electric drive axles, and in particular to an electric drive axle for commercial vehicles with an idler wheel structure. Background Art

[0002] At present, the drive forms applicable to new energy heavy-duty trucks are roughly divided into two types: central drive and electric drive axle. The central drive form has been widely used in heavy-duty trucks. Similar to traditional models, it generally uses an electric motor with a multi-speed reducer, and connects the rear axle through a transmission shaft to achieve power transmission. The structure is relatively simple, but it occupies a large space, which is not conducive to releasing battery space and affects vehicle endurance. Therefore, many OEMs have started research on electric drive axles.

[0003] At present, the existing electric drive axles generally adopt a gearbox powertrain mounted on the traditional structural axle. Most of the powertrains adopt parallel shaft gearboxes, and the shifting system is arranged on the powertrain. The power center of mass of the entire electric drive axle is relatively large, and the electric drive axle of commercial vehicles is installed on the suspension, which belongs to the unsprung mass. When the wheel bounces, the electric drive axle can reach a maximum acceleration of 50G, which makes the powertrain housing, the bridge housing, and the connecting bolts between the two bear great stress. At this time, ultra-high strength housing and bridge housing materials need to be selected, and the wall thickness of the housing and the bridge housing needs to be designed to be very thick, and a lot of reinforcing ribs are required to solve the problem of high stress between the housings. The span of the connecting bolts between the powertrain and the bridge housing needs to be designed to be very small and large-sized bolts need to be selected for connection; this makes the weight of the entire electric drive axle very heavy, and the longitudinal dimensions are all on one side of the bridge centerline, which is also very unfavorable for the application layout of the whole vehicle;

[0004] At present, the power transmission of electric drive axles generally adopts a reduction gear structure. Each pair of gears has a certain speed ratio distribution, which has the disadvantages of a large number of transmission chain gears and bearings, a complex structure, and a heavy transmission chain.

[0005] To take power under vehicle driving conditions, a certain vehicle speed is required. However, due to the speed limit of the power take-off oil pump, the working speed of the power take-off cannot be too fast. At the same time, the power take-off must have a large torque output. When the current electric drive axle arranges the power take-off solution, a pair of master and slave gears need to be designed separately to achieve the high torque and low speed requirements at the input end of the power take-off. The power take-off system has the disadvantages of a large number of gears and bearings, a complex structure, and a large weight. Summary of the invention

[0006] The technical problem to be solved by the present invention is that the existing electric drive axle of commercial vehicles has a complex structure, a large weight and is difficult to arrange.

[0007] In order to solve the above technical problems, the technical solution of the present invention is to provide a commercial vehicle electric drive axle with an idler structure, including a drive motor, an input shaft, a first intermediate shaft, a hollow center shaft, a second intermediate shaft, a differential assembly and a power take-off, wherein:

[0008] The driving motor is connected to an input shaft, and a primary driving gear is provided on the input shaft;

[0009] The first intermediate shaft is provided with an idler gear and a secondary driving gear, and the idler gear is meshedly connected with the primary driving gear;

[0010] The output end of the power take-off is connected to a driven wheel of the power take-off through an output shaft, and the driven wheel of the power take-off is meshed and connected with a secondary driving gear;

[0011] The differential assembly is provided with a left half shaft and a right half shaft, and the left half shaft and the right half shaft are respectively connected to the half shaft gears in the differential assembly, and the differential assembly is also provided with a four-stage driven gear;

[0012] The hollow center shaft sleeve is arranged on the right half shaft, and a three-stage driving gear, a second gear and a first gear are arranged thereon. The second gear and the first gear are respectively sleeved on the hollow center shaft through needle bearings. A shift gear hub is also arranged on the hollow center shaft. The shift gear hub is located between two needle bearings. A shift gear sleeve is arranged on the shift gear hub. The first gear is meshed and connected with an idler gear, and the second gear is meshed and connected with a secondary driving gear.

[0013] The second intermediate shaft and the first intermediate shaft are respectively located on both sides of the differential assembly. The second intermediate shaft is provided with a four-stage driving gear and a three-stage driven gear. The four-stage driving gear is meshed and connected with the four-stage driven gear, and the three-stage driven gear is meshed and connected with the three-stage driving gear.

[0014] Optionally, the drive motor is connected to the input shaft via a spline, the idler gear is connected to the first intermediate shaft via a spline, the shift gear hub is fixed to the hollow center shaft via a spline, and the third-stage driven gear is connected to the second intermediate shaft via a spline.

[0015] Optionally, the hollow center shaft is concentric with the left half shaft and the right half shaft, and tapered roller bearings are provided at both ends of the hollow center shaft, with one end fixed to the housing of the differential assembly and the other end fixed to the external powertrain housing.

[0016] Optionally, a differential lock assembly is provided on the left half shaft near the differential assembly.

[0017] Optionally, a coupling sleeve is provided at one end of the power take-off connected to the driven wheel of the power take-off, an external spline is provided on the output shaft where the driven wheel of the power take-off is located, the coupling sleeve is connected to the driven wheel of the power take-off through the external spline, and a spring is provided at the coupling sleeve of the power take-off.

[0018] Optionally, one end of the power take-off that is not connected to the driven wheel of the power take-off is connected to a power take-off oil pump via an internal spline.

[0019] In summary, the present invention has the following beneficial effects:

[0020] 1. The present invention arranges two intermediate shafts on both sides of the power output end respectively, and designs the central shaft into a hollow shaft structure and sleeves on the right half shaft. The central shaft can maximize the shift gear hub and the gear sleeve to approach the center line of the power output end, so that the center of mass of the electric drive bridge is close to the center line of the bridge housing, which solves the shortcomings of the parallel shaft electric drive bridge having large overall size, the size of the powertrain being offset on one side of the electric drive bridge, and the large distance between the center of mass of the powertrain and the center of the bridge housing. It is beneficial to the installation and layout space of the electric drive bridge on the whole vehicle, and solves the problem that the connecting bolts of the powertrain housing and the bridge housing are subjected to large stress. The housing can be designed as a housing and bridge housing with relatively thin walls, and ordinary materials can be selected, which can reduce reinforcing ribs and complex strength-increasing structures, reduce the specifications and quantity of connecting bolts, and make the electric drive bridge light in overall weight and simple in structure.

[0021] 2. The reducer of the present invention adopts an idler wheel solution. Under the first gear working condition, the entire power transmission is a 4-stage reduction structure. Under the second gear working condition, the entire power transmission is a 3-stage reduction structure. The power take-off driving wheel and the secondary driving wheel are shared, which can reduce one power take-off gear and some bearings, reduce the number of transmission chain gears and bearings, optimize the transmission chain structure, and have the advantage of specific lightweight of the entire transmission chain. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0023] Figure 2 This is a schematic diagram of power transmission in the first gear working condition of the present invention;

[0024] Figure 3 This is a schematic diagram of power transmission in the second gear working condition of the present invention;

[0025] In the figure: 1. driving motor; 2. input shaft; 3. idler gear; 4. second gear; 5. hollow center shaft; 6. first gear; 7. first intermediate shaft; 8. shift gear hub; 9. shift gear sleeve; 10. third-stage driven gear; 11. second intermediate shaft; 12. fourth-stage driven gear; 13. differential assembly; 14. differential lock assembly; 15. left half shaft; 16. right half shaft; 17. power take-off driven wheel; 18. power take-off; 19. power take-off oil pump; S1. first-stage driving gear; S2. second-stage driving gear; S3. third-stage driving gear; S4. fourth-stage driving gear. DETAILED DESCRIPTION

[0026] The following combination Figure 1-3 The present invention is described in further detail.

[0027] The present invention discloses a commercial vehicle electric drive axle with an idler wheel structure, which can be used for vehicles in different scenarios such as sanitation vehicles, logistics trucks, tractors, and bus tours, and has strong adaptability. Figure 1 , including a drive motor 1, an input shaft 2, a first intermediate shaft 7, a hollow center shaft 5, a second intermediate shaft 11, a differential assembly 13 and a power take-off 18, wherein:

[0028] The driving motor 1 is connected to the input shaft 2, and the input shaft 2 is provided with a primary driving gear S1;

[0029] The first intermediate shaft 7 is provided with an idler gear 3 and a secondary driving gear S2, and the idler gear 3 is meshedly connected with the primary driving gear S1;

[0030] The output end of the power take-off 18 is connected to the power take-off driven wheel 17 via an output shaft, and the power take-off driven wheel 17 is meshedly connected with the secondary driving gear S2;

[0031] The differential assembly 13 is provided with a left half shaft 15 and a right half shaft 16, which are respectively connected to the half shaft gears in the differential assembly 13, and the differential assembly 13 is also provided with a four-stage driven gear 12;

[0032] The hollow center shaft 5 is sleeved on the right half shaft 16, and is provided with a third-stage driving gear S3, a second-speed gear 4 and a first-speed gear 6. The second-speed gear 4 and the first-speed gear 6 are sleeved on the hollow center shaft 5 through needle bearings respectively. A shift gear hub 8 is also provided on the hollow center shaft 5. The shift gear hub 8 is located between two needle bearings. A shift gear sleeve 9 is provided on the shift gear hub 8. The first-speed gear 4 is meshed and connected with the idler gear 3, and the second-speed gear 6 is meshed and connected with the secondary driving gear S2.

[0033] The second intermediate shaft 11 and the first intermediate shaft 7 are respectively located on both sides of the differential assembly 13. The second intermediate shaft 11 is provided with a four-stage driving gear S4 and a three-stage driven gear 10. The four-stage driving gear S4 is meshed and connected with the four-stage driven gear 12, and the three-stage driven gear 10 is meshed and connected with the three-stage driving gear S3.

[0034] In a further embodiment, the drive motor 1 is splined to the input shaft 2, the idler gear 3 is splined to the first intermediate shaft 7, the shift gear hub 8 is splined to the hollow center shaft 5, and the third-stage driven gear 10 is splined to the second intermediate shaft 11.

[0035] In a further embodiment, the hollow center shaft 5 is concentric with the left half shaft 15 and the right half shaft 16, and tapered roller bearings are provided at both ends of the hollow center shaft 5, and one end is fixed to the housing of the differential assembly 13, and the other end is fixed to the external powertrain housing. A differential lock assembly 14 is provided on the left half shaft 15 near the differential assembly 13. When the electric drive axle slips in the first gear or second gear condition, the left half shaft 15 and the differential assembly 14 can be connected into one through the differential lock assembly 14 to solve the power distribution problem under the slipping condition.

[0036] In a further embodiment, a coupling sleeve is provided at one end of the power take-off 18 connected to the power take-off driven wheel 17, an external spline is provided on the output shaft where the power take-off driven wheel 17 is located, the coupling sleeve is connected to the power take-off driven wheel 17 through the external spline, a spring is provided at the coupling sleeve of the power take-off 18, and the end of the power take-off 18 not connected to the power take-off driven wheel 17 is connected to the power take-off oil pump 19 through an internal spline. When the power take-off 18 is not working, it relies on its own spring to reset. At this time, the power take-off 18 is not connected to the power take-off driven wheel 17. When the power take-off 18 is working, the power take-off coupling sleeve is connected to the power take-off driven wheel 17, and the power take-off driven wheel 17 drives the power take-off oil pump 19 to work. At this time, the secondary driving wheel S2 is used as the driving wheel of the power take-off 18. The power take-off system is designed at the front end of the shifting system, which can meet the dual needs of driving power take-off and parking power take-off of the electric drive bridge.

[0037] The first working condition of the present invention is as follows Figure 2 As shown, the shift actuator drives the shift gear sleeve 9 to move rightward, so that the shift gear hub 8 is connected to the first gear 6, and the power is transmitted to the idler gear 3 through the primary driving wheel S1, and then transmitted to the first gear 6 by the driven wheel 17 of the power take-off, and then transmitted to the second intermediate shaft 11 through the hollow center shaft 5, and then transmitted to the differential assembly 13 through the fourth-stage driven gear 12, and finally output by the left and right half shafts;

[0038] In the second gear, refer to Figure 3, the shift actuator drives the shift gear sleeve 9 to move leftward, so that the shift gear hub 8 is connected to the second gear 4, and the power is transmitted to the idler gear 3 through the first-stage driving wheel S1, and then to the second gear 4, and then to the second intermediate shaft 11 through the hollow center shaft 5, and then to the differential assembly 13 through the fourth-stage driven gear 12, and finally output by the left and right half shafts;

[0039] Under the neutral working condition, the shift sleeve 9 is in the middle position, at which time the first gear 6 and the second gear 4 are in an idling state, and there is no power output.

[0040] The present invention adopts an idler wheel solution. Under the first gear working condition, the idler wheel serves as the driven wheel of the first-stage gear pair and plays the role of the first-stage reduction. The entire power transmission is a 4-stage reduction structure. Under the second gear working condition, under the action of the idler wheel, the first-stage reduction ratio is the number of teeth of the second gear gear / the number of teeth of the first-stage driving wheel. The entire power transmission is a 3-stage reduction structure. The power take-off driving wheel 17 and the second-stage driving wheel S2 are shared, which can reduce one power take-off gear and some bearings, reduce the number of transmission chain gears and bearings, optimize the transmission chain structure, and make the entire transmission chain lightweight.

[0041] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A commercial vehicle electric drive axle with an idler wheel structure, characterized in that: It comprises a driving motor (1), an input shaft (2), a first intermediate shaft (7), a hollow central shaft (5), a second intermediate shaft (11), a differential assembly (13) and a power take-off (18), wherein: The driving motor (1) is connected to an input shaft (2), and a primary driving gear (S1) is provided on the input shaft (2); An idler wheel (3) and a secondary driving gear (S2) are provided on the first intermediate shaft (7), and the idler wheel (3) is meshingly connected with the primary driving gear (S1); The output end of the power take-off (18) is connected to a power take-off driven wheel (17) via an output shaft, and the power take-off driven wheel (17) is meshingly connected to a secondary driving gear (S2); The differential assembly (13) is provided with a left half shaft (15) and a right half shaft (16), and the left half shaft (15) and the right half shaft (16) are respectively connected to the half shaft gears in the differential assembly (13), and the differential assembly (13) is also provided with a four-stage driven gear (12); The hollow central shaft (5) is sleeved on the right half shaft (16), and is provided with a three-stage driving gear (S3), a second gear (4) and a first gear (6). The second gear (4) and the first gear (6) are sleeved on the hollow central shaft (5) through needle bearings respectively. A shift gear hub (8) is also provided on the hollow central shaft (5). The shift gear hub (8) is located between two needle bearings. A shift gear sleeve (9) is provided on the shift gear hub (8). The first gear (4) is meshedly connected with the idler gear (3), and the second gear (6) is meshedly connected with the secondary driving gear (S2). The second intermediate shaft (11) and the first intermediate shaft (7) are respectively located on both sides of the differential assembly (13); a fourth-stage driving gear (S4) and a third-stage driven gear (10) are provided on the second intermediate shaft (11); the fourth-stage driving gear (S4) is meshedly connected with the fourth-stage driven gear (12); and the third-stage driven gear (10) is meshedly connected with the third-stage driving gear (S3).

2. The commercial vehicle electric drive axle with an idler wheel structure according to claim 1, characterized in that: The drive motor (1) is connected to the input shaft (2) via a spline, the idler gear (3) is connected to the first intermediate shaft (7) via a spline, the shift gear hub (8) is fixed to the hollow center shaft (5) via a spline, and the third-stage driven gear (10) is connected to the second intermediate shaft (11) via a spline.

3. The commercial vehicle electric drive axle with an idler wheel structure according to claim 1, characterized in that: The hollow center shaft (5) is concentric with the left half shaft (15) and the right half shaft (16), and tapered roller bearings are provided at both ends of the hollow center shaft (5), one end of the hollow center shaft (5) is fixed to the housing of the differential assembly (13), and the other end is fixed to the external power assembly housing.

4. The commercial vehicle electric drive axle with an idler wheel structure according to claim 1, characterized in that: A differential lock assembly (14) is provided on the left half shaft (15) near the differential assembly (13).

5. The commercial vehicle electric drive axle with an idler wheel structure according to claim 1, characterized in that: A coupling sleeve is provided at one end of the power take-off (18) connected to the driven wheel (17) of the power take-off, an external spline is provided on the output shaft where the driven wheel (17) of the power take-off is located, the coupling sleeve is connected to the driven wheel (17) of the power take-off via the external spline, and a spring is provided at the coupling sleeve of the power take-off (18).

6. The commercial vehicle electric drive axle with an idler wheel structure according to claim 5, characterized in that: One end of the power take-off (18) not connected to the power take-off driven wheel (17) is connected to a power take-off oil pump (19) via an internal spline.

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