Low-stirring oil consumption transmission lubrication and heat dissipation mechanism and vehicle

Abstract

The application provides a low oil stirring loss transmission lubrication and heat dissipation mechanism and a vehicle, and relates to the technical field of vehicle engineering. The mechanism comprises a cavity shell, a gear shaft assembly, an oil pan, an oil pump, a heat exchanger and an oil pipe. The gear shaft assembly is installed in the cavity shell, the oil pan is connected to the bottom of the cavity shell, and the oil pan is located below the gear shaft assembly and extends along the gear shaft assembly bottom gear in a half-wrapping manner. The oil inlet pipe of the oil pump is in fluid communication with the bottom of the cavity of the cavity shell, the oil outlet pipe of the oil pump is in fluid communication with the heat exchanger, and the heat exchanger is in fluid communication with the cavity shell through the oil pipe. The mechanism breaks through the bottleneck of splash lubrication and natural heat dissipation, improves the heat dissipation power and oil temperature stability, prolongs the service life of lubricating oil, gears and bearings, enhances the transmission reliability and driving safety under high-temperature working conditions, and has the advantages of modular assembly, process nature, maintainability and system expansibility. The overall lubrication sufficiency, energy efficiency and heat management performance are coordinately improved.

Description

Technical Field

[0001] This invention relates to the field of vehicle engineering technology, and in particular to a low-stirring-oil-loss transmission lubrication and cooling mechanism and vehicle. Background Technology

[0002] As a key component of the power transmission system, the reliability, efficiency, and lifespan of the gearbox highly depend on the adequate lubrication and effective heat dissipation of its internal gears and shafts. In traditional mechanical gearboxes with single or multiple intermediate shafts, a bottom-immersion lubrication system is commonly used to ensure continuous oil supply to the lower intermediate shaft, output shaft, and corresponding gear pairs. This involves setting up a lubricating oil pool of a certain depth at the bottom of the gearbox housing, immersing part or all of the gears in the lower gear shaft assembly in the oil. While this design achieves basic lubrication under static conditions, it leads to significant churning losses under high-speed operating conditions. The high-speed rotating gear teeth repeatedly cut into and agitate the stationary or low-speed flowing oil, generating severe turbulence, bubble entrainment, and viscous shear, causing a large amount of mechanical energy to be irreversibly converted into heat. This not only significantly reduces transmission efficiency but also causes a sharp increase in local oil temperature, accelerating lubricant oxidation and deterioration, and inducing micro-pitting, galling, and even tooth breakage.

[0003] Meanwhile, existing transmission cooling systems generally suffer from inherent defects such as low heat dissipation power density, long heat transfer paths, and poor structural integration. Mainstream solutions often employ passive oil pan natural convection cooling or simply add an external air-cooled oil cooler. These solutions have limited heat exchange area, low specific heat capacity of the cooling medium (air), large flow channel pressure drop, and are easily affected by ambient temperature. While some heavy-duty vehicles are equipped with water-cooled oil coolers, these are often independent modules connected to the transmission oil circuit via hoses, posing risks of interface leakage, poor connection reliability under vibration conditions, and delayed thermal response. More importantly, traditional cooling structures are not adapted to the spatial distribution of the oil churning heat source. The high-temperature core area (i.e., the lower oil-immersed gear meshing area) is far from the heat dissipation interface, requiring heat to be dissipated through multiple layers of metal casing and oil convection before it can be released. This results in high thermal resistance and a large temperature gradient, further exacerbating localized overheating and material fatigue. Summary of the Invention

[0004] The purpose of this invention is to provide a low-agitation-loss transmission lubrication and cooling mechanism and vehicle, in order to solve the technical problems of excessive temperature rise, shortened life and increased operational risks caused by excessive agitation loss and insufficient cooling capacity in traditional transmissions.

[0005] In a first aspect, the low-stirring-loss transmission lubrication and heat dissipation mechanism provided by the present invention includes: a housing, a gear shaft assembly, an oil pan, an oil pump, a heat exchanger, and oil pipes; The gear shaft assembly is installed inside the cavity housing, the oil pan is connected to the bottom of the cavity housing, and the oil pan is located below the gear shaft assembly and extends circumferentially along the bottom gear of the gear shaft assembly as a semi-enclosed portion; The oil pump's inlet pipe is in fluid communication with the bottom of the inner cavity of the housing, the oil pump's outlet pipe is in fluid communication with the heat exchanger, and the heat exchanger is in fluid communication with the housing via the oil pipe.

[0006] In conjunction with the first aspect, the present invention provides a first possible implementation of the first aspect, wherein the oil pan adopts a segmented structure and includes a first oil pan, a second oil pan and a third oil pan arranged sequentially along the gearbox axis; The cavity housing includes a front housing, a front support plate, a main housing, and a rear housing. The front housing, the front support plate, and the rear housing are spaced apart along the gearbox axial direction and are respectively connected to the main housing. The first oil pan is installed at the bottom of the cavity between the front housing and the front support plate, the second oil pan is installed at the bottom of the cavity between the front support plate and the main housing, and the third oil pan is installed at the bottom of the cavity between the main housing and the rear housing. The semi-enclosed portion includes a guide channel or arc-shaped surface disposed in the first oil pan, the second oil pan, and the third oil pan.

[0007] In conjunction with the first aspect, the present invention provides a second possible implementation of the first aspect, wherein the semi-enclosed portion covers the bottom gear of the gear shaft assembly at an angle of 120° to 240°.

[0008] In conjunction with the first aspect, the present invention provides a third possible implementation of the first aspect, wherein the oil pipe extends axially along the top of the cavity of the housing, and the oil pipe is provided with a directional oil injection hole toward the gear shaft assembly.

[0009] In conjunction with the third possible implementation of the first aspect, the present invention provides a fourth possible implementation of the first aspect, wherein the oil pipe is provided with a plurality of spaced-apart directional oil injection holes along the axial direction, and the axis of each oil injection hole forms an angle of 20° to 60° with the gear meshing line of the corresponding gear shaft assembly.

[0010] In conjunction with the first aspect, the present invention provides a fifth possible implementation of the first aspect, wherein both the oil pump and the heat exchanger are mounted on the rear housing.

[0011] In conjunction with the first aspect, the present invention provides a sixth possible implementation of the first aspect, wherein the oil pump has a built-in overflow valve, and the vent of the overflow valve is in fluid communication with the inner cavity of the housing.

[0012] In conjunction with the first aspect, the present invention provides a seventh possible implementation of the first aspect, wherein the low churning loss transmission lubrication and cooling mechanism further includes a coolant housing disposed outside the oil pump or the cavity housing, wherein the inlet and outlet of the coolant housing are respectively connected to the coolant circulation system and are in fluid communication with the cold side flow channel of the heat exchanger.

[0013] In conjunction with the seventh possible implementation of the first aspect, the present invention provides an eighth possible implementation of the first aspect, wherein the side wall of the oil pump is provided with a heat dissipation channel, and the heat dissipation channel is in fluid communication with the coolant housing or the cold side flow channel of the heat exchanger.

[0014] Secondly, the vehicle provided by the present invention is equipped with the low oil churning loss transmission lubrication and cooling mechanism described in the first aspect.

[0015] The embodiments of this invention bring the following beneficial effects: On the one hand, by adopting a semi-enclosed oil pan design instead of the traditional fully submerged oil sump design, only a local circumferential area of ​​the bottom gear of the gear shaft assembly comes into contact with the lubricating oil. This significantly reduces the effective immersion area and agitation volume of the high-speed rotating gear in the oil, thereby greatly suppressing the agitation resistance and the resulting shear heat generation, reducing agitation power loss, and fundamentally alleviating the problem of oil temperature spikes caused by overheating during agitation. On the other hand, a closed-loop oil circuit system with forced circulation and external enhanced heat dissipation is constructed. The oil pump actively draws oil from the low-pressure area at the bottom of the housing, and after efficient cooling by a high-efficiency external heat exchanger, the cooled lubricating oil is precisely returned to the key friction pair area inside the housing through oil pipes. This design breaks through the heat dissipation bottlenecks of traditional splash lubrication, natural convection, or simple air cooling, improves heat dissipation power, and significantly enhances oil temperature stability. This not only extends the service life of the lubricating oil and core components such as bearings and gears, but also improves transmission reliability and driving safety under high-temperature conditions.

[0016] Furthermore, the modular assembly of the oil pan and housing, along with the integrated assembly of the heat exchanger and oil pump, balances manufacturability, ease of maintenance, and system scalability. The overall solution achieves a synergistic leap in lubrication system energy efficiency and thermal management performance without sacrificing adequate lubrication.

[0017] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the specific embodiments or related technologies of the present invention, the drawings used in the description of the specific embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 An exploded view of a low-stirring-loss transmission lubrication and cooling mechanism provided in an embodiment of the present invention; Figure 2 A front view of a low-stirring-loss transmission lubrication and cooling mechanism provided in an embodiment of the present invention; Figure 3 A cross-sectional view of the oil pump and heat exchanger of the low-stirring-loss transmission lubrication and cooling mechanism provided in an embodiment of the present invention.

[0020] Icons: 100-Cavity housing; 110-Front housing; 120-Front support plate; 130-Main housing; 140-Rear housing; 200-Gear shaft assembly; 300-Oil pan; 301-First oil pan; 302-Second oil pan; 303-Third oil pan; 400-Oil pump; 401-Relief valve; 402-Oil pump inlet; 403-First branch; 404-Second branch; 500-Heat exchanger; 501-First fluid passage of the heat exchanger; 502-Second fluid passage of the heat exchanger; 600-Oil pipe. Detailed Implementation

[0021] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used only to describe differences in name and should not be construed as indicating or implying relative importance. Physical quantities in formulas, unless otherwise specified, should be understood as basic quantities in the International System of Units (SI), or derived quantities derived from basic quantities through mathematical operations such as multiplication, division, differentiation, or integration.

[0023] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0024] like Figure 1 and Figure 2 As shown, the low-stirring-loss transmission lubrication and heat dissipation mechanism provided in this embodiment of the invention includes: a housing 100, a gear shaft assembly 200, an oil pan 300, an oil pump 400, a heat exchanger 500, and an oil pipe 600; the gear shaft assembly 200 is installed inside the housing 100, the oil pan 300 is connected to the bottom of the housing 100, and the oil pan 300 is located below the gear shaft assembly 200 and extends circumferentially along the bottom gear of the gear shaft assembly 200 as a semi-enclosed portion; the oil inlet pipe of the oil pump 400 is in fluid communication with the bottom of the inner cavity of the housing 100, the oil outlet pipe of the oil pump 400 is in fluid communication with the heat exchanger 500, and the heat exchanger 500 is in fluid communication with the housing 100 via the oil pipe 600.

[0025] The housing 100 constitutes the main load-bearing housing of the transmission, made of high-strength die-cast aluminum alloy, and forms a closed chamber inside to accommodate gears, shafts, and lubricating oil. The gear shaft assembly 200 includes an input shaft, output shaft, intermediate shaft (single or multiple), gears for each gear position, and synchronizer components, arranged axially within the housing 100. The bottom gear (i.e., the lowest point of the pitch circle of the driving / driven gear closest to the bottom surface of the housing) is the main site for oil churning. The oil pan 300 is an independent, detachable functional module, rigidly connected to the bottom flange of the housing 100 by an array of bolts. Its top opening is sealed to the bottom surface of the housing 100, and the two together form a non-fully submerged oil storage space. This oil pan 300 is not a traditional U-shaped deep pool, but a semi-enclosed part extending circumferentially along the bottom gear of the gear shaft assembly 200, only covering a partial arc segment below the gear pitch circle, so that only this part is exposed when the gear rotates. The arc-shaped area is in contact with the oil, while the remaining circumferential area is in a dry state or a splash transition zone. The oil pump 400 is an external gear pump or a cycloidal rotor pump, installed outside the housing 100 (preferably outside the rear housing 140). Its oil inlet pipe extends into the lowest point of the bottom of the inner cavity of the housing 100 (i.e., the area with the highest static pressure of the oil) to achieve stable oil suction. The oil outlet pipe is connected to the high-temperature side inlet of the heat exchanger 500. The heat exchanger 500 is a plate-fin or shell-and-tube oil cooler with high specific surface area and low pressure drop characteristics. Its cold side flow channel is connected to the vehicle's coolant circulation system (it can be connected to the engine cooling circuit or an independent electronic control cooling circuit). The oil pipe 600 is an oil-resistant and heat-resistant synthetic rubber hose or a stainless steel rigid pipe. One end is connected to the outlet of the heat exchanger 500, and the other end extends into the top area of ​​the inner cavity of the housing 100. It is equipped with directional oil injection holes for targeted oil supply to high-level friction pairs (such as bearings, synchronizer forks, and meshing tooth surfaces).

[0026] Furthermore, the oil pan 300 adopts a segmented structure and includes a first oil pan 301, a second oil pan 302, and a third oil pan 303 arranged sequentially along the gearbox axial direction; the cavity shell 100 includes a front shell 110, a front support plate 120, a main shell 130, and a rear shell 140, the front shell 110, the front support plate 120, and the rear shell 140 are spaced apart along the gearbox axial direction and are respectively connected to the main shell 130; the first oil pan 301 is correspondingly installed at the bottom of the cavity between the front shell 110 and the front support plate 120, the second oil pan 302 is correspondingly installed at the bottom of the cavity between the front support plate 120 and the main shell 130, and the third oil pan 303 is correspondingly installed at the bottom of the cavity between the main shell 130 and the rear shell 140; the semi-enclosed portion includes a guide groove or an arc-shaped surface disposed on the first oil pan 301, the second oil pan 302, and the third oil pan 303.

[0027] The front housing 110 and the front support plate 120, the front support plate 120 and the main housing 130, and the main housing 130 and the rear housing 140 each form an independent transverse cavity to accommodate different gear sets or support bearings. Correspondingly, the first oil pan 301 is fixed to the bottom flange of the cavity between the front housing 110 and the front support plate 120 by a group of M8 bolts; the second oil pan 302 is fixed to the bottom flange between the front support plate 120 and the main housing 130; and the third oil pan 303 is fixed to the bottom flange between the main housing 130 and the rear housing 140. The semi-enclosed portion of each oil pan is set as a concave guide groove with an arc-shaped cross-section. The center of curvature coincides with the center of the pitch circle of the corresponding gear, and the groove depth is 0.8 to 1.2 times the gear module. Limiting flanges are provided on both sides of the guide groove to prevent oil from overflowing under vibration conditions. Optionally, the surface of the guide groove is micro-textured (Ra=0.4–0.8). (μm) to enhance oil film adhesion stability and avoid local dry friction caused by high-speed oil splashing. This segmented structure takes into account manufacturing tolerance distribution, assembly sequence optimization and convenience of local maintenance and replacement - when the wear of a certain gear increases the risk of oil leakage, only the corresponding section of the oil pan needs to be removed for maintenance, without draining the entire tank of oil or disassembling the main housing.

[0028] Furthermore, the semi-enclosed portion covers the bottom gear of the gear shaft assembly 200 at an angle of 120° to 240°, balancing oil churning suppression and minimum lubrication assurance. Specifically, with the gear pitch circle as the reference circle, the central angle corresponding to the semi-enclosed portion is configured to be 120° to 240°. This angle can be designed based on the coupled modeling of gear meshing phase, oil surface tension, and centrifugal oil slinging critical speed, so as to select an angle value with clear physical basis and flexible adaptability to working conditions.

[0029] Furthermore, the oil pipe 600 extends axially along the top of the inner cavity of the housing 100, and the oil pipe 600 is provided with a directional oil injection hole facing the gear shaft assembly 200.

[0030] In an optional embodiment, the axis of each injection hole forms an angle of 20° to 60° with the gear meshing line of the corresponding gear shaft assembly 200.

[0031] Each injection hole's axial direction is positioned in three-dimensional space: its projection lies within the plane of the gear end face, forming a certain angle with the gear meshing line (i.e., the common tangent of the pitch circles of the two gears) at that position. This angle design ensures that the jet direction avoids the normal direction of the meshing line (preventing impact damage to the oil film) while possessing sufficient tangential component to propel the lubricating oil along the tooth surface to the tooth root, promoting oil film renewal in the tooth root bending fatigue sensitive area. The injection hole outlet is equipped with a micro-guide lip to control the jet diffusion angle to ≤15°, ensuring concentrated oil jets and controllable momentum decay, avoiding excessive atomization that could cause air resistance or low-level oil accumulation. This targeted injection structure significantly improves the oil supply response speed and oil film maintenance capability of high-position components (such as synchronizer locking teeth and output shaft rear bearings), solving the inherent defects of traditional splash lubrication such as delayed oil supply and uneven distribution at high speeds.

[0032] Furthermore, both the oil pump 400 and the heat exchanger 500 are mounted on the rear housing 140. A dedicated mounting boss is provided on the outer side of the rear housing 140. The oil pump 400 is pre-tightened to the boss by double-ended studs and disc spring washers. A fluororubber O-ring seal is provided between its housing and the rear housing 140. The heat exchanger 500 is fixed to the side of the oil pump 400 housing by an L-shaped bracket in a side-mounted manner. The inlet and outlet flanges of the two are connected by quick-connect clamps. This layout significantly shortens the length of the high-temperature oil circuit, reduces heat loss and pressure fluctuations along the way, and facilitates modular assembly and after-sales replacement by vehicle manufacturers.

[0033] The oil pump 400 has a built-in relief valve 401, and the vent of the relief valve 401 is in fluid communication with the inner cavity of the housing 100. The vent of the relief valve 401 is directly connected to the bottom of the inner cavity of the housing 100 via a short pipe, ensuring unobstructed backflow of overpressure oil and avoiding local high pressure stagnation or seal rupture. This design automatically opens and closes to protect the oil pump and pipeline system under abnormal operating conditions such as oil circuit blockage, heat exchanger scaling, or excessive viscosity at low temperature startup.

[0034] The low-churning-loss transmission lubrication and cooling mechanism also includes a coolant housing located outside the oil pump 400 or the housing 100. The inlet and outlet of the coolant housing are connected to the coolant circulation system and are in fluid communication with the cold-side flow channel of the heat exchanger 500. The coolant housing can be connected to the bottom or side of the housing 100, or it can be cast integrally with the main housing 130. Alternatively, the coolant housing can be shaped to fit the outer contour of the housing 100 and have an S-shaped flow channel inside. The coolant housing has standardized inlet and outlet ports, which are respectively connected to the low-pressure branch and return manifold of the vehicle's coolant circulation system. This structure does not require the addition of a separate cooling circuit but reuses existing cooling resources, conforming to the platform development principle of commercial vehicles.

[0035] like Figure 1 and Figure 3As shown, the oil pump 400 and heat exchanger 500 are integrated. Oil in the housing 100 flows into the oil pump 400 through the oil pump inlet 402, and then flows into the oil pipe 600 through either the first branch 403 or the second branch 404. The lubricating oil exchanges heat in the outer housing of the oil pump 400 via the first branch 403 and the second branch 404, and the heat can be directly transferred to the heat exchanger 500. Furthermore, the first liquid passage 501 and the second liquid passage 502 of the heat exchanger 500 are both located within this housing. Coolant flows into the heat exchanger 500 from one of the first liquid passage 501 and the second liquid passage 502, and then flows out through the other of the first liquid passage 501 and the second liquid passage 502, circulating while simultaneously exchanging heat with the lubricating oil through this housing.

[0036] Furthermore, the side wall of the oil pump 400 is provided with a heat dissipation channel, which is in fluid communication with the coolant housing or the cold side flow channel of the heat exchanger 500. The heat dissipation channel is a cavity structure cast in the side wall of the oil pump 400, with a rectangular cross-section, extending along the height direction, and its two ends are respectively connected to the inlet / outlet of the coolant housing; the inner wall of the channel is treated with sandblasting and anodizing to enhance the radiative heat dissipation capacity; when the heat exchanger 500 is momentarily overloaded or the coolant flow is insufficient, the heat dissipation channel can bear about 15% to 20% of the rated heat dissipation through heat conduction and natural convection.

[0037] The vehicle provided in this embodiment of the invention is equipped with the low-stirring-loss transmission lubrication and cooling mechanism described in the above embodiments. The vehicle is a heavy-duty tractor or a pure electric urban bus, with its transmission mounted at the front end of the drive axle and directly connected to the motor output flange. The vehicle control system includes a lubrication-thermal management collaborative control module, which collects real-time signals of oil temperature (PT100 sensor), oil pressure (piezoresistive sensor), motor speed, and torque. When the detected oil temperature > 110°C and remains above 10 seconds, the ECU instructs the electronic water pump to increase the coolant flow rate by 20%. When the oil temperature > 125°C, power reduction protection is triggered, and the instrument panel warning light illuminates.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A low-agitation-loss transmission lubrication and cooling mechanism, characterized in that, include: Cavity housing (100), gear shaft assembly (200), oil pan (300), oil pump (400), heat exchanger (500) and oil pipe (600); The gear shaft assembly (200) is installed inside the cavity housing (100), the oil pan (300) is connected to the bottom of the cavity housing (100), and the oil pan (300) is located below the gear shaft assembly (200) and extends circumferentially along the bottom gear of the gear shaft assembly (200) as a semi-enclosed portion; The oil inlet pipe of the oil pump (400) is in fluid communication with the bottom of the inner cavity of the cavity shell (100), the oil outlet pipe of the oil pump (400) is in fluid communication with the heat exchanger (500), and the heat exchanger (500) is in fluid communication with the cavity shell (100) via the oil pipe (600).

2. The low-churning-loss transmission lubrication and cooling mechanism according to claim 1, characterized in that, The oil pan (300) adopts a segmented structure and includes a first oil pan (301), a second oil pan (302) and a third oil pan (303) arranged sequentially along the gearbox axis. The cavity housing (100) includes a front housing (110), a front support plate (120), a main housing (130), and a rear housing (140). The front housing (110), the front support plate (120), and the rear housing (140) are spaced apart along the gearbox axial direction and are respectively connected to the main housing (130). The first oil pan (301) is installed at the bottom of the cavity between the front housing (110) and the front support plate (120), the second oil pan (302) is installed at the bottom of the cavity between the front support plate (120) and the main housing (130), and the third oil pan (303) is installed at the bottom of the cavity between the main housing (130) and the rear housing (140). The semi-enclosed portion includes a guide groove or arc-shaped surface disposed on the first oil pan (301), the second oil pan (302), and the third oil pan (303).

3. The low-stirring-loss transmission lubrication and cooling mechanism according to claim 1 or 2, characterized in that, The semi-enclosed portion covers the bottom gear of the gear shaft assembly (200) at an angle of 120° to 240°.

4. The low-churning-loss transmission lubrication and cooling mechanism according to claim 1, characterized in that, The oil pipe (600) extends axially along the top of the inner cavity of the cavity shell (100), and the oil pipe (600) is provided with a directional oil injection hole facing the gear shaft assembly (200).

5. The low-churning-loss transmission lubrication and cooling mechanism according to claim 4, characterized in that, The oil pipe (600) is provided with a plurality of spaced directional oil injection holes along the axial direction, and the axis of each oil injection hole forms an angle of 20° to 60° with the gear meshing line of the corresponding gear shaft assembly (200).

6. The low-churning-loss transmission lubrication and cooling mechanism according to claim 2, characterized in that, The oil pump (400) and the heat exchanger (500) are both mounted on the rear housing (140).

7. The low-churning-loss transmission lubrication and cooling mechanism according to claim 1, characterized in that, The oil pump (400) has a built-in overflow valve (401), and the vent of the overflow valve (401) is in fluid communication with the inner cavity of the housing (100).

8. The low-churning-loss transmission lubrication and cooling mechanism according to claim 1, characterized in that, It also includes a coolant housing disposed outside the oil pump (400) or the cavity housing (100), wherein the inlet and outlet of the coolant housing are respectively connected to the coolant circulation system and are in fluid communication with the cold side flow channel of the heat exchanger (500).

9. The low-churning-loss transmission lubrication and cooling mechanism according to claim 8, characterized in that, The side wall of the oil pump (400) is provided with a heat dissipation channel, which is in fluid communication with the coolant housing or the cold side flow channel of the heat exchanger (500).

10. A vehicle, characterized in that, The vehicle is equipped with a low-stirring-loss transmission lubrication and cooling mechanism as described in any one of claims 1 to 9.

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