Differential mechanism for electric driving of electric automobile

Abstract

The invention relates to the technical field of differential mechanisms, and discloses a differential mechanism for electric driving of an electric vehicle. Comprising a differential mechanism shell, oil guide holes are formed in the differential mechanism shell, a straight-line-shaped shaft is movably connected into the differential mechanism shell, the two ends of the straight-line-shaped shaft are each sleeved with two planetary gears, and half axle gears are arranged at the two output ends of the differential mechanism shell. The oil guide hole is located in the meshing position of the half axle gear and the planetary gear, when the electric drive assembly operates, lubricating oil of the electric drive assembly can directly enter the differential mechanism from the oil guide hole and makes full contact with the half axle gear, the planetary gear, the ball gasket, the flat gasket and the differential shell, and a layer of oil film is formed on the surface of each assembly. And finally, the friction force among the half axle gear, the planetary gear, the ball gasket, the flat gasket and the differential shell is reduced, and the abnormal sound of the differential mechanism generated by friction is eliminated.

Description

Technical Field

[0001] The present invention relates to the technical field of differentials, in particular to a differential for electric driving of an electric vehicle. Background Art

[0002] The car differential is a mechanism that enables the left and right (or front and rear) drive wheels to rotate at different speeds. It is mainly composed of left and right half-shaft gears, two planetary gears and a gear rack. The function is to make the left and right wheels roll at different speeds when the car is turning or driving on uneven roads, that is, to ensure that the drive wheels on both sides perform pure rolling motion. The differential is installed to adjust the speed difference between the left and right wheels. In four-wheel drive, in order to drive the four wheels, all wheels must be connected. If the four wheels are mechanically connected together, the car cannot rotate at the same speed when driving in a curve. In order to make the car's rotation speed basically consistent when driving in a curve, an intermediate differential needs to be added to adjust the speed difference between the front and rear wheels. The power output of traditional passenger cars comes from the engine and gearbox. The engine is noisy during operation, which can cover most of the abnormal noises on the passenger car, so that the abnormal noise is not obvious for the comfort experience of the driver and passengers. The power output of new energy vehicles comes from the electric drive assembly, which is powered by batteries and converted into mechanical energy through the motor. The motor transfers the mechanical energy to the reducer, which finally transfers the mechanical energy to the wheel end to drive the vehicle. Compared with engines, motors have the advantage of low operating noise, so new energy vehicles have a quieter passenger compartment than traditional fuel passenger cars.

[0003] When new energy vehicles are in the following three conditions: high torque turning, high torque U-turn or driving in an "8" shape, the electric drive assembly will produce a low-frequency buzzing noise. Through further analysis, it was found that the abnormal noise was generated by the differential in the electric drive assembly reducer. Because new energy vehicles have a quiet passenger compartment, the abnormal noise of the differential is particularly obvious after being transmitted to the passenger compartment, which seriously affects the comfort of the entire vehicle and the experience of the driver and passengers. Summary of the invention

[0004] 1. Technical issues to be resolved In view of the deficiencies in the prior art, the present invention provides an electric drive differential for an electric vehicle. According to the friction formula F=μN, F is the friction force, μ is the contact surface friction coefficient, and N is the vertical pressure. The friction coefficient μ and the vertical pressure N are effectively reduced by corresponding methods, thereby achieving the effect of reducing friction and optimizing the problem of abnormal noise of the differential. The differential housing has four oil guide holes, and the oil guide holes are located at the meshing position of the half-shaft gear and the planetary gear. When the electric drive assembly is running, the lubricating oil of the electric drive assembly will directly enter the inside of the differential from the oil guide holes, fully contact with the half-shaft gear, the planetary gear, the ball gasket, the flat gasket and the differential housing, and form an oil film on the surface of each component. Therefore, under the joint action of the molybdenum disulfide coating of the ball gasket and the flat gasket, the surface friction coefficient of the half-shaft gear, the planetary gear, the ball gasket, the flat gasket and the differential housing is further reduced, and finally the friction between the half-shaft gear, the planetary gear, the ball gasket, the flat gasket and the differential housing is reduced, and finally the abnormal noise of the differential caused by friction is eliminated, etc., and the problem of large abnormal noise in the operation of the differential is solved.

[0005] (II) Technical solution In order to solve the above technical problems, the present invention provides the following technical solutions: comprising a differential housing, wherein an oil guide hole is arranged inside the differential housing, a straight shaft is movably connected inside the differential housing, and the motion trajectory of the straight shaft is consistent with that of the differential housing, two planetary gears are sleeved at both ends of the straight shaft, and half-shaft gears are arranged at both output ends of the differential housing, half-shaft splines are arranged inside the half-shaft gears, and the half-shaft splines are meshed with the planetary gears.

[0006] Through the above technical solution, the motor output power enters the reducer. After being decelerated by the reducer, when the power drives the main reduction gear to rotate, the differential housing rotates with the main reduction gear. The straight shaft is fixed on the housing, and a planetary gear is installed at each end. When the housing rotates, it can drive the straight shaft to rotate, and then drive the planetary gear to rotate. The rotation of the planetary gear drives the half-shaft gear meshing with it to rotate, and the internal spline of the half-shaft gear drives the half-shaft to rotate, and finally transmits the power to the wheel. According to the friction formula F=μN, F is the friction force, μ is the friction coefficient of the contact surface, and N is the vertical pressure. The friction coefficient μ and the vertical pressure N are effectively reduced by corresponding methods, thereby achieving the effect of reducing friction and optimizing the problem of abnormal noise of the differential.

[0007] Preferably, a ball washer is provided on the side surface of the planetary gear, and the ball washer is located between the planetary gear and the inner surface of the differential housing.

[0008] Through the above technical solution, the ball gasket is used to silence the rotation of the planetary gear. When the vehicle is running normally in a straight line, the output speeds of the left and right half-axles are the same, and the differential state is non-differential. At this time, there is no mutual extrusion between the planetary gear and the half-axle gear. Therefore, no abnormal pressure is generated between the planetary gear and the ball gasket, or between the half-axle gear and the flat gasket, and a small clearance fit is maintained.

[0009] Preferably, a flat gasket is provided on the side surface of the side gear, and the flat gasket is located between the side gear and the inner surface of the differential housing.

[0010] Through the above technical solution, the ball gasket and the flat gasket are matched to facilitate the formation of an oil film at the rear, thereby reducing abnormal noise when the differential is used.

[0011] Preferably, the differential housing is directly connected to the main reduction gear of the speed reducer, and the differential housing is a carrier of all components of the entire differential.

[0012] Through the above technical solution, the differential is installed on the reducer, which is one of the sub-modules of the electric drive assembly. The electric drive assembly also includes a motor controller and a motor. The output shaft of the motor is connected to the input shaft of the reducer. The differential is fixed on the main reduction gear of the reducer. The half-axle gears of the differential are connected to the drive shaft through internal splines, driving the wheels to rotate, thereby driving the car to move.

[0013] Preferably, the oil guide hole is connected to the reduction gear box, and the oil guide hole can quickly pour the lubricating oil in the reduction gear box into the interior of the differential housing.

[0014] Through the above technical solution, the oil guide hole is located at the meshing position of the half-shaft gear and the planetary gear. When the electric drive assembly is running, the lubricating oil of the electric drive assembly will directly enter the inside of the differential from the oil guide hole, fully contact with the half-shaft gear, planetary gear, ball gasket, flat gasket and differential case, and form a layer of oil film on the surface of each component. Therefore, under the joint action of the molybdenum disulfide coating of the ball gasket and the flat gasket, the surface friction coefficient of the half-shaft gear, planetary gear, ball gasket, flat gasket and differential case is further reduced, and finally the friction between the half-shaft gear, planetary gear, ball gasket, flat gasket and differential case is reduced, and finally the abnormal noise of the differential caused by friction is eliminated.

[0015] Preferably, the planetary gear rotates around a straight-line shaft, and the planetary gear is configured as a bevel gear with the tooth surface facing the interior of the differential.

[0016] Through the above technical solution, the planetary gears and the half-shaft gears are subjected to a shaping process to optimize the tooth surface shapes of the planetary gears and the half-shaft gears, so as to reduce the impact and vibration during meshing, thereby reducing the excitation that produces abnormal noise.

[0017] Preferably, the coating between the ball washer and the planetary gear and the inner surface of the differential housing is molybdenum disulfide grease.

[0018] Through the above technical scheme, the surface coating of the ball gasket and the flat gasket is molybdenum disulfide. Solid, semi-fluid and fluid grease containing molybdenum disulfide components have excellent lubrication properties for mechanical friction parts working in extreme pressure environments. The molybdenum disulfide coating on the surface of the ball gasket and the flat gasket can reduce the friction coefficient of the gasket surface. Ultimately, when the meshing force of the planetary gear and the half-shaft gear fluctuates, the friction can be reduced when the ball gasket and the flat gasket are subjected to the same pressure, thereby alleviating the probability of abnormal noise.

[0019] Preferably, the half-shaft gear matches with the new energy vehicle transmission half-shaft to output mechanical energy.

[0020] Through the above technical solution, the rotation of the planetary gear drives the half-shaft gear meshing with it to rotate, and the internal spline of the half-shaft gear drives the half-shaft to rotate, and finally transmits power to the wheel.

[0021] Preferably, the coating between the flat gasket and the inner surface of the half-shaft gear and the differential housing is molybdenum disulfide grease.

[0022] Through the above technical solution, the surface coating of the ball gasket and the flat gasket is molybdenum disulfide, which cooperates with the lubricating oil poured into the oil guide hole, and can greatly reduce the abnormal noise when the differential is used.

[0023] Preferably, double spiral oil grooves are provided on both inner walls of the differential housing.

[0024] Through the above technical solution, the double spiral oil groove exists on the outer surface of the differential housing, making it convenient to discharge the lubricating oil after use inside the differential housing. At the same time, the double spiral oil groove can be used to slowly pour the lubricating oil into the inside of the differential housing to lubricate the moving components in the differential and reduce abnormal noise.

[0025] Compared with the prior art, the present invention provides a differential for electric drive of an electric vehicle, which has the following beneficial effects: The invention provides a differential for electric driving of an electric vehicle, comprising a differential housing, wherein an oil guide hole is arranged inside the differential housing, wherein a straight shaft is movably connected inside the differential housing, wherein two planetary gears are sleeved at both ends of the straight shaft, and half-shaft gears are arranged at two output ends of the differential housing, and the differential housing has four oil guide holes, wherein the oil guide holes are located at meshing positions of the half-shaft gears and the planetary gears. When the electric driving assembly is running, lubricating oil of the electric driving assembly directly enters the interior of the differential from the oil guide holes, fully contacts with the half-shaft gears, the planetary gears, the ball washers, the flat washers and the differential housing, and forms an oil film on the surface of each component, thereby further reducing the surface friction coefficient of the half-shaft gears, the planetary gears, the ball washers, the flat washers and the differential housing under the joint action of the molybdenum disulfide coatings of the ball washers and the flat washers, and finally reducing the friction between the half-shaft gears, the planetary gears, the ball washers, the flat washers and the differential housing, and finally eliminating the abnormal noise of the differential caused by the friction. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The figure is a schematic diagram of the three-dimensional structure of a differential for electric drive of an electric vehicle in an embodiment of the present invention.

[0027] Figure 2 Schematic diagram of the ceiling panel structure in an embodiment of the present invention.

[0028] Figure 3 It is a schematic diagram of the upward view of the structure of the suspended ceiling keel in an embodiment of the present invention.

[0029] Among them: 1. Differential housing; 2. Slotted shaft; 3. Planetary gear; 4. Ball gasket; 5. Axle gear; 6. Flat gasket; 7. Axle spline; 8. Double helical oil groove; 9. Oil guide hole. DETAILED DESCRIPTION

[0030] 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.

[0031] See also Figure 1-3The present invention provides an electric drive differential for an electric vehicle, comprising a differential case 1, an oil guide hole 9 is arranged inside the differential case 1, a straight shaft 2 is movably connected inside the differential case 1, and the motion trajectory of the straight shaft 2 is consistent with that of the differential case 1, two planetary gears 3 are sleeved at both ends of the straight shaft 2, and half-shaft gears 5 are arranged at both output ends of the differential case 1, and the tooth surface shapes of the planetary gears 3 and the half-shaft gears 5 are optimized by performing a shaping process on the planetary gears 3 and the half-shaft gears 5 to reduce the impact and vibration during meshing, thereby reducing the excitation of abnormal noise, a half-shaft spline 7 is arranged inside the half-shaft gear 5, and the half-shaft spline 7 is meshed with the planetary gear 3, the straight shaft 2 is fixed on the differential case 1, and a planetary gear 3 is assembled at each end, and when the differential case 1 rotates, the straight shaft 2 can be driven to rotate, thereby driving the planetary gears When the wheel 3 rotates, the planetary gear 3 rotates and drives the half-shaft gear 5 meshing with it to rotate. The internal spline 7 of the half-shaft gear 5 drives the half-shaft to rotate, and finally transmits the power to the wheel. The side surface of the planetary gear 3 is provided with a ball gasket 4, and the ball gasket 4 is located between the planetary gear 3 and the inner surface of the differential case 1. The side surface of the half-shaft gear 5 is provided with a flat gasket 6, and the flat gasket 6 is located between the half-shaft gear 5 and the inner surface of the differential case 1. The coating between the ball gasket 4 and the planetary gear 3 and the inner surface of the differential case 1 is molybdenum disulfide grease, and the coating between the flat gasket 6 and the half-shaft gear 5 and the inner surface of the differential case 1 is molybdenum disulfide grease. By changing the surface coating of the ball gasket 4 and the flat gasket 6 to molybdenum disulfide, the solid, semi-fluid and fluid grease containing molybdenum disulfide components have excellent lubrication performance for mechanical friction parts working under extreme pressure environments.

[0032] During the application of the reducer, the motor outputs power and enters the reducer. After being decelerated by the reducer, when the power drives the main reduction gear to rotate, the differential housing 1 rotates with the main reduction gear. The straight shaft 2 is fixed on the differential housing 1, and a planetary gear 3 is installed at each end. When the differential housing 1 rotates, it can drive the straight shaft 2 to rotate, and then drive the planetary gear 3 to rotate. The rotation of the planetary gear 3 drives the half-shaft gear 5 meshing with it to rotate, and the internal spline 7 of the half-shaft gear 5 drives the half-shaft to rotate, and finally transmits the power to the wheel.

[0033] When the vehicle is running normally in a straight line, the output speeds of the left and right half-axles are the same, and the differential is in a non-differential state. At this time, there is no mutual extrusion between the planetary gear 3 and the half-axle gear 5, so there is no abnormal pressure between the planetary gear 3 and the ball gasket 4, or between the half-axle gear 5 and the flat gasket 6, and a small clearance fit is maintained.

[0034] When the vehicle is performing high-torque cornering, high-torque U-turn or "8" driving conditions, the output speeds of the left and right half-axles are different, and the differential state is differential. At this time, the half-axle gear 5 and the planetary gear 3 mesh and rotate. Affected by the fluctuation of the gear meshing force, the half-axle gear 5 and the planetary gear 3 will shake abnormally during rotation. Therefore, the planetary gear 3 and the ball gasket 4, or the half-axle gear 5 and the flat gasket 6 are squeezed, and the pressure on the ball gasket 4 and the flat gasket 6 increases. The contact area between the planetary gear 3 and the ball gasket 4, or the half-axle gear 5 and the flat gasket 6 increases, so that the planetary gear 3 and the ball gasket 4, or the half-axle gear 5 and the flat gasket 6 slide against each other, and the friction force increases, causing abnormal noise in the differential.

[0035] According to the friction formula F=μN, F is the friction force, μ is the contact surface friction coefficient, and N is the vertical pressure. In this implementation case, the friction coefficient μ and the vertical pressure N are effectively reduced through corresponding methods, thereby achieving the effect of reducing friction and optimizing the problem of abnormal noise in the differential.

[0036] The differential housing 1 is directly connected to the main reduction gear of the speed reducer. The differential housing 1 is the carrier of the components of the entire differential. The oil guide hole 9 is connected to the speed reducer. The oil guide hole 9 can quickly pour the lubricating oil in the reduction gearbox into the interior of the differential housing 1. The planetary gear 3 rotates around the straight shaft 2. The planetary gear 3 is a bevel gear setting with the tooth surface facing the interior of the differential. The half-shaft gear 5 is matched with the new energy vehicle transmission half-shaft to output mechanical energy. The inner walls on both sides of the differential housing 1 are provided with double spiral oil grooves 8. The differential housing 1 has four oil guide holes 9. The oil guide holes 9 are located at the meshing position of the half-shaft gear 5 and the planetary gear 3. When the electric drive assembly is running, the lubricating oil of the electric drive assembly will directly enter the interior of the differential from the oil guide hole 9, fully contact with the half-shaft gear 5, the planetary gear 3, the ball gasket 4, the flat gasket 6 and the differential housing 1, and form a layer of oil film on the surface of each component, so that under the joint action of the molybdenum disulfide coating of the ball gasket 4 and the flat gasket 6, the surface friction coefficient of the half-shaft gear 5, the planetary gear 3, the ball gasket 4, the flat gasket 6 and the differential housing 1 is further reduced.

[0037] In this embodiment, the planetary gear 3 and the half-shaft gear 5 are subjected to a shaping process to optimize the tooth surface shapes of the planetary gear 3 and the half-shaft gear 5 so as to reduce the impact and vibration during meshing, thereby reducing the excitation that produces abnormal noise.

[0038] At the same time, in this embodiment, when the meshing force fluctuation between the planetary gear 3 and the half-shaft gear 5 causes abnormal noise excitation, this embodiment changes the surface coating of the ball gasket 4 and the flat gasket 6 to molybdenum disulfide. Solid, semi-fluid, and fluid grease containing molybdenum disulfide components have excellent lubrication properties for mechanical friction parts working under extreme pressure environments. The molybdenum disulfide coating on the surface of the ball gasket 4 and the flat gasket 6 can reduce the friction coefficient of the gasket surface. Finally, when the meshing force fluctuation between the planetary gear 3 and the half-shaft gear 5 occurs, the friction can be reduced when the ball gasket 4 and the flat gasket 6 are subjected to the same pressure, thereby alleviating the probability of abnormal noise. Finally, in this embodiment, the differential housing 1 has four oil guide holes 9, which are located at the meshing position of the half-shaft gear 5 and the planetary gear 3. When the electric drive assembly is running, the lubricating oil of the electric drive assembly will directly enter the inside of the differential from the oil guide holes 9, fully contacting with the half-shaft gear 5, the planetary gear 3, the ball gasket 4, the flat gasket 6 and the differential housing 1, forming an oil film on the surface of each component, thereby further reducing the surface friction coefficient of the half-shaft gear 5, the planetary gear 3, the ball gasket 4, the flat gasket 6 and the differential housing 1 under the joint action of the molybdenum disulfide coating of the ball gasket 4 and the flat gasket 6, and finally reducing the friction between the half-shaft gear 5, the planetary gear 3, the ball gasket 4, the flat gasket 6 and the differential housing 1, and finally eliminating the abnormal noise of the differential caused by friction.

[0039] When in use, during the application of the reducer, the motor outputs power into the reducer. After being decelerated by the reducer, when the power drives the main reduction gear to rotate, the differential case 1 rotates with the main reduction gear. The straight shaft 2 is fixed on the case 1, and a planetary gear 3 is installed at each end. When the case 1 rotates, it can drive the straight shaft 2 to rotate, and then drive the planetary gear 3 to rotate. The rotation of the planetary gear 3 drives the half-shaft gear 5 meshing with it to rotate. The internal spline 7 of the half-shaft gear 5 drives the half-shaft to rotate, and finally transmits the power to the wheel. When the vehicle is driving normally in a straight line, , the left and right half-shaft output speeds are the same, and the differential state is non-differential. At this time, there is no mutual extrusion between the planetary gear 3 and the half-shaft gear 5, so there is no abnormal pressure between the planetary gear 3 and the ball gasket 4, or between the half-shaft gear 5 and the flat gasket 6, and a small clearance is maintained. The molybdenum disulfide coating on the surface of the ball gasket 4 and the flat gasket 6 can reduce the friction coefficient of the gasket surface. Finally, when the meshing force fluctuation between the planetary gear 3 and the half-shaft gear 5 occurs, the friction can be reduced when the ball gasket 4 and the flat gasket 6 are subjected to the same pressure, thereby alleviating the probability of abnormal noise.

[0040] 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 differential for electric driving of an electric vehicle, comprising a differential housing (1), characterized in that: An oil guide hole (9) is provided inside the differential housing (1), a straight shaft (2) is movably connected inside the differential housing (1), and the movement trajectory of the straight shaft (2) is consistent with that of the differential housing (1), two planetary gears (3) are sleeved at both ends of the straight shaft (2), and half-shaft gears (5) are provided at both output ends of the differential housing (1), and half-shaft splines (7) are provided inside the half-shaft gears (5), and the half-shaft splines (7) are meshed with the planetary gears (3).

2. The electric vehicle electric drive differential according to claim 1, characterized in that: A ball washer (4) is provided on the side surface of the planetary gear (3), and the ball washer (4) is located between the planetary gear (3) and the inner surface of the differential housing (1).

3. The electric vehicle electric drive differential according to claim 1, characterized in that: A flat gasket (6) is provided on the side surface of the half-shaft gear (5), and the flat gasket (6) is located between the half-shaft gear (5) and the inner surface of the differential housing (1).

4. The electric vehicle electric drive differential according to claim 1, characterized in that: The differential housing (1) is directly connected to the main reduction gear of the speed reducer, and the differential housing (1) is a carrier for all components of the entire differential.

5. The electric vehicle electric drive differential according to claim 1, characterized in that: The oil guide hole (9) is connected to the reduction gear box; the oil guide hole (9) can quickly pour the lubricating oil in the reduction gear box into the interior of the differential housing (1).

6. The electric drive differential of an electric vehicle according to claim 1, characterized in that: The planetary gear (3) rotates around the straight shaft (2); the planetary gear (3) is a bevel gear, and the tooth surface faces the interior of the differential.

7. The electric vehicle electric drive differential according to claim 2, characterized in that: The coating between the ball gasket (4) and the inner surface of the planetary gear (3) and the differential housing (1) is molybdenum disulfide grease.

8. The electric vehicle electric drive differential according to claim 1, characterized in that: The half-shaft gear (5) is matched with the new energy vehicle transmission half-shaft to output mechanical energy.

9. The electric drive differential of an electric vehicle according to claim 3, characterized in that: The coating between the flat gasket (6) and the inner surface of the half-shaft gear (5) and the differential housing (1) is molybdenum disulfide grease.

10. The electric vehicle electric drive differential according to claim 1, characterized in that: Double spiral oil grooves (8) are provided on the inner walls of both sides of the differential housing (1).

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