Lubricating structure of differential mounting cavity of electric drive axle

Abstract

The invention discloses a lubricating structure for a differential mounting cavity of an electric drive axle. The lubricating structure mainly comprises an electric drive axle shell and the differential mounting cavity in the electric drive axle shell. An oil pool is arranged on the lower portion of a differential installation cavity, bearing pedestals with integrated die-casting bearing pedestal bodies are arranged on the two sides of the cavity, and a closed-loop lubricating system is formed in cooperation with an upper flow guide groove, a lubricating oil channel and a lower oil return groove. The main reduction gear adopts a helical gear structure, drives oil pool lubricating oil to enter the lubricating oil channel through the diversion trench during rotation, and returns to an oil pool through the oil return groove after being shunted to lubricate the bearing seat through the branch oil channel. The oil blocking part and the wedge-shaped oil distributing part are innovatively arranged, multi-stage distribution of oil is achieved, and the problems of oil retention and unsmooth circulation of a traditional structure are effectively solved through cooperation with a flow guide / oil return channel formed by the trapezoidal bearing seat body. According to the structure, the lubricating oil capacity is reduced, the bearing lubrication coverage rate is increased, the transmission efficiency is improved, and the manufacturing cost is optimized.

Description

Technical Field

[0001] The invention relates to the field of drive axles, and in particular to a lubrication structure of a differential mounting cavity of an electric drive axle. Background Art

[0002] As the core component of vehicle power transmission, the structural design of the electric drive axle assembly directly affects the transmission efficiency and reliability. The traditional drive axle assembly usually includes a drive axle housing and an internally integrated main reducer, differential and half-axle assembly. The driven gear of the main reducer mostly adopts a helical bevel gear structure, and the differential is supported in the drive axle housing through bearings.

[0003] However, this type of structure has the following significant defects: in order to meet the load-bearing strength requirements, the differential mounting cavity and the half-axle sleeve mounting cavity of the drive axle housing are of large structural dimensions, resulting in a high demand for internal lubricating oil capacity, a disordered lubricating oil circulation path, and low stirring efficiency, which causes additional energy loss and increases the cost of oiling; although the traditional helical bevel gears can bring up the bottom lubricating oil by rotating on the tooth surface, their tooth shape characteristics cause the oil to splash mainly along the helical tooth side of the bevel gear, and the oil forms a retention area on the back of the bevel gear, further reducing the lubrication efficiency; the bearing seat body of the bearing seats at both ends of the differential housing is die-cast as a whole with the electric drive axle housing, and the mounting surface of the bearing seat body for installing the bearing cover is located on the same plane as the rear reinforcement ring. There is a lack of flow diversion design, which causes the lubricating oil to flow obstructed near the bearing seat, making it difficult for the oil to circulate, exacerbating the problem of low bearing lubrication efficiency. Summary of the invention

[0004] The purpose of the present invention is to provide a drive axle assembly with an improved lubrication system to address the corresponding deficiencies of the prior art. By using more helical cylindrical gears for the driven gears of the main reducer and optimizing the lubrication path, the lubricating oil circulation efficiency is improved and the problem of insufficient lubrication of key components is solved.

[0005] The specific technical solution adopted by the present invention is as follows: A lubrication structure for a differential mounting cavity of an electric drive axle comprises an electric drive axle housing, wherein an oil pool is provided at the lower part of a differential mounting cavity provided in the electric drive axle housing, a differential is rotatably arranged in the differential mounting cavity, a part of a main reduction gear fixedly connected to the differential contacts the oil pool, and a flange for connecting an end cover is provided at the cavity opening of the differential mounting cavity, characterized in that: bearing seats for supporting the differential are provided on both sides of the differential mounting cavity, a lubricating oil passage communicating with a half-axle sleeve mounting cavity is provided between the bearing seat and the flange for connecting the end cover, lubricating oil guide grooves are provided on the left and right sides of the upper cavity wall of the differential mounting cavity, the guide grooves are communicated with the lubricating oil passage, and oil return grooves are provided on the left and right sides of the lower part of the differential mounting cavity, one end of the oil return groove is communicated with the lubricating oil passage, and the other end is communicated with the oil pool, the lubricating oil is brought from the oil pool to the guide groove through the main reduction gear, and flows back to the oil pool through the lubricating oil passage and the oil return groove, so that a lubricating oil circulation passage is formed in the differential mounting cavity.

[0006] Preferably, the upper cavity wall of the differential mounting cavity is provided with an oil baffle portion extending toward the center of the differential mounting cavity, a first oil distribution channel is formed between the upper edge of the oil baffle portion and the upper cavity wall of the differential mounting cavity, a second oil distribution channel is formed between the side edge of the oil baffle portion and the bearing seat, and the first oil distribution channel and the guide groove are located on the same extension line.

[0007] Preferably, the bearing seat includes a bearing cover and a bearing seat body die-cast integrally with the electric drive axle housing, the axial cross-section of the bearing seat body is trapezoidal, a guide groove is formed between the upper inclined surface and the upper cavity wall of the differential mounting cavity, and an oil return groove is formed between the lower inclined surface and the lower cavity wall of the differential mounting cavity.

[0008] Preferably, the bearing seat extends toward the first oil distribution channel to form a wedge-shaped oil distribution portion to distribute the lubricating oil into the guide groove and the second oil distribution channel.

[0009] Preferably, the oil inlet of the guide groove and the oil outlet of the oil return groove are expanded to form trumpet-shaped openings.

[0010] Preferably, the main reduction gear is a helical cylindrical gear.

[0011] The beneficial effects of the present invention are as follows: 1. High-efficiency lubrication circulation system design: The lubricating oil in the oil pool is brought into the guide groove through the rotation of the main reduction gear. The guide groove, lubricating oil channel and return oil groove form a closed loop circulation to improve the flow efficiency of the lubricating oil. Compared with the traditional structure, the amount of lubricating oil required is reduced, and the lubricating oil circulates in an orderly manner in the differential installation cavity, effectively reducing gear stirring losses.

[0012] 2. Accurately distribute lubricating oil to improve the utilization rate of lubricating oil: the oil baffle blocks most of the lubricating oil, and a small part of the lubricating oil enters the first oil distribution channel. The lubricating oil entering the first oil distribution channel flows from the wedge-shaped oil distribution part into the guide groove and the second oil distribution channel, realizing multi-stage lubricating oil distribution, accurately controlling the flow direction of the lubricating oil, and improving the utilization rate of the lubricating oil. The lubricating oil entering the guide groove and the lubricating oil entering the second oil distribution channel are respectively used to lubricate the tapered roller bearings arranged in the bearing seat.

[0013] 3. The main reducer gear is a helical cylindrical gear. Compared with the traditional helical bevel gear, it can make the cooling oil splash toward both sides of the main reducer gear, eliminate the problem of oil retention on one side of the helical bevel gear, and form an orderly circulation of the oil. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural schematic diagram of the present invention; Figure 2 It is a schematic diagram of the assembly structure of the present invention.

[0015] Among them: 1-electric drive axle housing, 6-differential, 7-main reduction gear, 8-bearing seat, 14-differential installation cavity, 15-semi-axle sleeve installation cavity, 16-oil pool, 17-lubricating oil channel, 18-lubricating oil guide groove, 19-return oil groove, 20-oil baffle, 21-first oil distribution channel, 22-second oil distribution channel, 23-wedge-shaped oil distribution part, 24-flange, 8-bearing seat, 81-bearing cover, 82-bearing seat body DETAILED DESCRIPTION

[0016] like Figure 1 to Figure 2 As shown, a lubrication structure of a differential mounting cavity of an electric drive axle comprises an electric drive axle housing 1, a differential mounting cavity 14 provided in the electric drive axle housing 1 is provided with an oil pool 16 at the lower part, a differential 6 is rotatably arranged in the differential mounting cavity 14, the differential 6 comprises a differential housing and a differential mechanism, a main reduction gear 7 is fixed to a flange provided on the differential housing by bolts, a part of the main reduction gear 7 is in contact with the oil pool 16, a cavity opening of the differential mounting cavity 14 is provided with a flange 24 for connecting an end cover, and the differential mounting cavity 14 is divided into two sides. A bearing seat 8 for supporting a differential housing of a differential 6 is provided, and the differential 6 is supported in the bearing seat 8 by a tapered roller bearing. A lubricating oil passage 17 communicating with the half-axle sleeve installation cavity 15 is provided between the bearing seat 8 and the flange 24 for connecting the end cover. Lubricating oil guide grooves 18 are provided on the left and right sides of the upper cavity wall of the differential installation cavity 14, and the guide grooves 18 are communicated with the lubricating oil passage 17. Oil return grooves 19 are provided on the left and right sides of the lower part of the differential installation cavity 14, and one end of the oil return groove 19 is communicated with the lubricating oil passage 17, and the other end is communicated with the oil pool 16; The bearing seat 8 includes a bearing cover 81 and a bearing seat body 82 integrally die-cast with the electric drive axle housing 1. The axial cross-section of the bearing seat body 82 is trapezoidal. A guide groove 18 is formed between the upper inclined surface and the upper cavity wall of the differential mounting cavity 14, and an oil return groove 19 is formed between the lower inclined surface and the lower cavity wall of the differential mounting cavity 14. The oil inlet of the guide groove 18 and the oil outlet of the oil return groove 19 are expanded to form a trumpet-shaped opening, and the trumpet-shaped opening gradually changes from large to small from the oil port to the inside of the guide groove 18 or the oil return groove 19. The structure is used to gather and guide the flow of lubricating oil, and the lubricating oil is brought from the oil pool to the guide groove 18 through the main reduction gear 7, and flows back to the oil pool 16 through the lubricating oil channel 17 and the return oil groove 19, so that a lubricating oil circulation channel is formed in the differential installation cavity 14. The main reduction gear 7 is a helical cylindrical gear. Compared with the helical bevel gear in the prior art, the helical cylindrical gear can make the cooling oil fall toward both sides of the main reduction gear 7, so as to prevent the cooling oil from being retained in the helical bevel gear and increase the circulation rate; The upper cavity wall of the differential mounting cavity 14 is provided with an oil baffle portion 20 extending toward the center of the differential mounting cavity 14, and the oil baffle portion 20 is approximately triangular in shape. A first oil distribution channel 21 is formed between the upper edge of the oil baffle portion 20 and the upper cavity wall of the differential mounting cavity 14, and a second oil distribution channel 22 is formed between the side edge of the oil baffle portion 20 and the bearing seat 8. The first oil distribution channel 21 and the guide groove 18 are located on the same extension line. The oil baffle portion 20 blocks most of the lubricating oil brought up by the main reduction gear 7, and most of the lubricating oil returns to the oil pool, and a small part of the lubricating oil enters the first oil distribution channel 21. The bearing seat 8 extends toward the first oil distribution channel 21 to form a wedge-shaped oil distribution portion 23, but the wedge-shaped oil distribution portion 23 does not extend into the first oil distribution channel 21. The wedge-shaped oil distribution portion 23 diverts the lubricating oil into the guide groove 18 and the second oil distribution channel 22. The lubricating oil entering the guide groove 18 and the lubricating oil entering the second oil distribution channel 22 are respectively used to lubricate the two sides of the tapered roller bearing.

[0017] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification made to the present invention by those skilled in the art without departing from the spirit of the present invention shall fall within the protection scope of the present invention.

Claims

1. A lubrication structure for a differential mounting cavity of an electric drive axle, comprising an electric drive axle housing (1), wherein the lower portion of a differential mounting cavity (14) provided in the electric drive axle housing (1) is provided with an oil pool (16), a differential (6) is rotatably arranged in the differential mounting cavity (14), a portion of a main reduction gear (7) fixedly connected to the differential (6) is in contact with the oil pool (16), and a cavity opening of the differential mounting cavity (14) is provided with a flange (24) for connecting an end cover, characterized in that: Bearing seats (8) for supporting the differential (6) are respectively provided on both sides of the differential installation cavity (14); a lubricating oil passage (17) communicating with the half-axle sleeve installation cavity (15) is provided between the bearing seat (8) and the flange (24) for connecting the end cover; lubricating oil guide grooves (18) are respectively provided on the left and right sides of the upper cavity wall of the differential installation cavity (14); the guide grooves (18) are communicated with the lubricating oil passage (17); and oil return grooves (19) are respectively provided on the left and right sides of the lower part of the differential installation cavity (14); one end of the oil return groove (19) is communicated with the lubricating oil passage (17) and the other end is communicated with the oil pool (16); the lubricating oil is brought from the oil pool to the guide groove (18) through the main reduction gear (7), and flows back to the oil pool (16) through the lubricating oil passage (17) and the oil return groove (19), so that a lubricating oil circulation passage is formed in the differential installation cavity (14).

2. The lubrication structure of the differential mounting cavity of the electric drive axle according to claim 1, characterized in that: An oil retaining portion (20) extending toward the center of the differential mounting cavity (14) is provided on the upper cavity wall of the differential mounting cavity (14); a first oil distribution passage (21) is formed between the upper edge of the oil retaining portion (20) and the upper cavity wall of the differential mounting cavity (14); a second oil distribution passage (22) is formed between the side edge of the oil retaining portion (20) and the bearing seat (8); and the first oil distribution passage (21) and the guide groove (18) are located on the same extension line.

3. The lubrication structure of the differential mounting cavity of the electric drive axle according to claim 1, characterized in that: The bearing seat (8) comprises a bearing cover (81) and a bearing seat body (82) integrally die-cast with the electric drive axle housing (1); the bearing seat body (82) has a trapezoidal axial cross-section, a guide groove (18) is formed between the upper inclined surface and the upper cavity wall of the differential mounting cavity (14), and an oil return groove (19) is formed between the lower inclined surface and the lower cavity wall of the differential mounting cavity (14).

4. The lubrication structure of the differential mounting cavity of the electric drive axle as claimed in claim 2, characterized in that: The bearing seat (8) extends toward the first oil distribution channel (21) to form a wedge-shaped oil distribution portion (23) for distributing the lubricating oil into the guide groove (18) and the second oil distribution channel (22).

5. The lubrication structure of the differential mounting cavity of the electric drive axle according to claim 1, characterized in that: The oil inlet of the guide groove (18) and the oil outlet of the oil return groove (19) are both expanded to form trumpet-shaped openings.

6. The lubrication structure of the differential mounting cavity of the electric drive axle according to claim 1, characterized in that: The main reduction gear (7) is a helical cylindrical gear.

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