Differential mechanism and automobile

Abstract

The differential mechanism comprises a differential mechanism shell and a planetary gear shaft, and the differential mechanism shell is provided with a first shaft hole; the planetary gear shaft is inserted into the first shaft hole and provided with a gear matching part, and the outer surface of the planetary gear shaft is provided with a first oil groove extending to the gear matching part. According to the planetary gear, the first oil groove extending to the gear matching part is formed in the outer surface of the planetary gear shaft, and when being sputtered or flowing to the outer surface of the planetary gear shaft, lubricating oil can enter the gear matching part along the first oil groove, so that a friction pair between the planetary gear and the planetary gear shaft is lubricated and cooled; the lubricating effect on the planetary gear and the planetary gear shaft is improved, and the use performance and the service life of the differential mechanism, the transmission system and the reduction gearbox are improved.

Description

Technical Field

[0001] The present application relates to the field of lubrication technology, and in particular to a differential and a car. Background Art

[0002] In the vehicle's transmission system, the differential is one of the key components of the transmission system, and plays an important role in transmitting torque and speed and driving wheels. With the promotion and popularization of new energy vehicles, users have put forward higher requirements for the driving performance of vehicles. Compared with traditional gearboxes, the electric drive reduction gearbox used in new energy vehicles has the characteristics of fast response, large torque impact, small amount of lubricating oil, and low oil viscosity. Due to the small amount of lubricating oil in the electric drive reduction gearbox, higher requirements are also put forward for the design of the internal lubrication system of the differential.

[0003] During the operation of the differential of an electric vehicle, due to the small amount of lubricating oil provided, the amount of oil that can enter each friction pair for lubrication is also small. When the planetary gear rotates relative to the planetary gear shaft, a large amount of heat will be generated between the two due to friction. If they cannot be lubricated and cooled in time, the planetary gear and / or the planetary gear shaft will be damaged due to overheating, which will affect the service life and performance of the differential, transmission system and reduction gearbox. Utility Model Content

[0004] One of the purposes of the present application is to provide a differential to solve the problem in the prior art that the amount of lubricating oil between the planetary gear shaft and the planetary gear is small, and the friction pair of the planetary gear shaft and the planetary gear cannot be lubricated and cooled in time; the second purpose is to provide a car.

[0005] In order to achieve the above purpose, the technical solution adopted in this application is as follows:

[0006] A differential comprising:

[0007] a differential housing having a first shaft hole;

[0008] A planetary gear shaft is inserted into the first shaft hole, the planetary gear shaft has a gear matching portion, and the outer surface of the planetary gear shaft has a first oil groove extending to the gear matching portion.

[0009] According to the above technical means, when the lubricating oil is splashed or flows to the outer surface of the planetary gear shaft, it can enter the gear mating part along the first oil groove, thereby lubricating and cooling the friction pair between the planetary gear and the planetary gear shaft, improving the lubrication effect of the planetary gear and the planetary gear shaft, and improving the performance and service life of the differential, transmission system and reduction gear box.

[0010] Furthermore, the first oil groove is arranged along the axial direction of the planetary gear shaft; and a plurality of the first oil grooves are arranged in sequence along the circumferential direction of the planetary gear shaft.

[0011] According to the above technical means, the length of the first oil groove is equal to the length of the planetary gear shaft, and can be directly formed by milling the outer surface of the planetary gear shaft, and the manufacturing process is simple; in addition, the first oil groove can be connected to the first shaft hole, so that the lubricating oil can enter and exit the differential housing through the gap between the first oil groove and the first shaft hole. Multiple first oil grooves are arranged in sequence along the circumference of the planetary gear shaft, which can uniformly lubricate the planetary gear shaft and the planetary gear friction pair in the circumferential direction, improve the lubrication and cooling effect between the planetary gear shaft and the planetary gear, and avoid local overheating.

[0012] Furthermore, the gear matching parts are provided at both ends of the planetary gear shaft, and a half-shaft avoidance part is provided between the two gear matching parts.

[0013] According to the above technical means, it is conducive to the assembly of planetary gears and half-shaft gears. The half-shaft avoidance part is used to avoid the transmission half-shaft inserted in the half-shaft gear, so that the end of the transmission half-shaft can extend out of the half-shaft gear, thereby improving the connection reliability between the transmission half-shaft and the half-shaft gear.

[0014] Furthermore, a second axial hole and a second oil groove are sequentially provided along the direction from the outside to the inside of the differential housing, the axis of the second axial hole is perpendicular to the axis of the first axial hole, the second oil groove is coaxially arranged with the second axial hole, and the diameter of the second oil groove is larger than the diameter of the second axial hole.

[0015] According to the above technical means, a preset gap can be provided in the radial direction between the cylindrical inner wall surface of the second oil groove and the journal of the half-shaft gear, so that the lubricating oil in the second shaft hole can enter the interior of the differential case through the second oil groove.

[0016] Furthermore, a second shaft hole is provided on both sides of the differential housing, a spiral oil guide groove is provided on the inner wall of the second shaft hole, and the spiral oil guide grooves on both sides of the differential housing have opposite rotation directions.

[0017] According to the above technical means, when the differential is running, the lubricating oil can enter the second shaft hole through the spiral oil guide groove, which can increase the amount of lubricating oil entering the second shaft hole, thereby increasing the amount of lubricating oil entering the differential housing from the second oil hole and the second oil groove, which is beneficial to lubricate the parts inside the differential housing. The spiral oil guide grooves on both sides of the differential housing rotate in opposite directions, which facilitates the lubricating oil in the external oil pool of the differential to be directed to the inside of the differential housing through the spiral oil guide grooves on both sides when the differential housing rotates.

[0018] Furthermore, the differential case also includes an oil storage chamber coaxially arranged with the second shaft hole, the oil storage chamber is located between the second shaft hole and the second oil groove, and the diameter of the oil storage chamber is between the diameter of the second oil groove and the diameter of the second shaft hole.

[0019] According to the above technical means, a stepped oil guide channel can be formed, so that a part of the lubricating oil flows through the spline mating part on the half-shaft gear and then leaks into the internal cavity of the differential through the mating clearance, and another part of the lubricating oil enters the interior of the differential housing through the second oil groove, so as to facilitate lubrication of the friction surface between the half-shaft gear and the inner wall of the differential housing.

[0020] Furthermore, the inner wall of the differential case has a half-shaft gear mating surface and a planetary gear mating surface; the half-shaft gear mating surface is provided with a third oil groove, and the second oil groove is connected to the third oil groove; the planetary gear mating surface is provided with a fourth oil groove, and the first shaft hole, the first oil groove and the fourth oil groove are connected.

[0021] According to the above technical means, the lubricating oil in the second oil groove can flow into the third oil groove, thereby lubricating and cooling the mating surface of the half-shaft gear on the differential case; the lubricating oil in the first oil groove can flow to the mating surface of the planetary gear through the fourth oil groove, lubricating and cooling the mating surface of the planetary gear, and lubricating the friction parts between the gear and the differential case, which is beneficial to improving the performance and service life of the half-shaft gear, planetary gear and differential case.

[0022] Furthermore, a first liner is provided on the mating surface of the half-shaft gear, and a second liner is provided on the mating surface of the planetary gear. Both the first liner and the second liner are provided with a plurality of oil holes.

[0023] According to the above technical means, the liner can reduce the wear of the side gear and the planetary gear, and can also play a role of buffering and shock absorption, which is conducive to extending the service life of the side gear and the planetary gear. The oil hole on the liner facilitates the lubricating oil to enter the gap between the liner and the inner wall of the differential case and the gap between the liner and the gear through the oil hole, thereby achieving effective lubrication of various components.

[0024] Furthermore, on the first gasket or the second gasket, the distances between the plurality of oil holes and the gasket axis vary periodically.

[0025] According to the above technical means, the lubrication area is increased by unequally spaced arrangement of multiple oil holes, which can avoid the phenomenon of local overheating in the annular area without oil holes caused by equidistant distribution of multiple oil holes.

[0026] A car comprises the above-mentioned differential.

[0027] Beneficial effects of this application:

[0028] (1) By arranging a first oil groove on the outer surface of the planetary gear shaft, the friction pair between the planetary gear shaft and the planetary gear can be lubricated and cooled, thereby optimizing the lubrication of the mating portion between the planetary gear shaft and the planetary gear; and by combining the second oil groove, the oil storage cavity, the third oil groove, the fourth oil groove, the fifth oil groove and the oil holes on the gasket, the limited amount of lubricating oil can be fully utilized to achieve the lubrication and cooling of the friction pair between the components, thereby ensuring the functional reliability of the differential assembly and improving the life of the electric drive reduction box system.

[0029] (2) The present application provides a preset distance between the second oil groove and the journal of the half-shaft gear, thereby facilitating the lubricating oil in the second shaft hole and the oil storage chamber to enter the third oil groove and the mating surface of the half-shaft gear through the second oil groove, thereby facilitating lubrication of the mating surface of the half-shaft gear, the first liner, the half-shaft gear and other components. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A cross-sectional view of a differential housing provided in an embodiment of the present application Figure 1 ;

[0031] Figure 2 A schematic diagram of the structure of a planetary gear shaft provided in an embodiment of the present application;

[0032] Figure 3 A cross-sectional view of a differential provided in an embodiment of the present application;

[0033] Figure 4 A cross-sectional view of a differential housing provided in an embodiment of the present application Figure 2 ;

[0034] Figure 5 A schematic diagram of the structure of a first gasket provided in an embodiment of the present application;

[0035] Figure 6 A schematic diagram of the structure of the second pad provided in an embodiment of the present application.

[0036] Among them, 1-differential housing; 11-first shaft hole; 12-second shaft hole; 121-spiral oil guide groove; 13-second oil groove; 14-oil storage chamber; 15-semi-axle gear mating surface; 151-third oil groove; 16-planetary gear mating surface; 17-differential housing window; 18-fifth oil groove; 19-first pin hole; 2-planetary gear shaft; 21-gear mating part; 22-first oil groove; 23-semi-axle avoidance part; 24-second pin hole; 3-first liner; 31-first oil hole; 4-second liner; 41-second oil hole; 5-fixing pin; 6-semi-axle gear; 7-planetary gear. DETAILED DESCRIPTION

[0037] The following will describe the implementation methods of the present application with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. The present application can also be implemented or applied through other different specific implementation methods, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be understood that the preferred embodiments are only for illustrating the present application, not for limiting the scope of protection of the present application.

[0038] It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present application, and thus the drawings only show components related to the present application rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed at will, and the component layout may also be more complicated.

[0039] See also Figures 1 to 6 This embodiment provides a differential, including a differential housing 1 and a planetary gear shaft 2, wherein the differential housing 1 has a first shaft hole 11, and the planetary gear shaft 2 is inserted into the first shaft hole 11. Figure 1 and Figure 3 The planetary gear shaft 2 has a gear matching portion 21 for matching with the planetary gear 7, and the outer surface of the planetary gear shaft 2 has a first oil groove 22 extending to the gear matching portion 21, as shown in FIG. Figure 2 As shown, when the lubricating oil is splashed or flows to the outer surface of the planetary gear shaft 2, it can enter the gear mating part 21 along the first oil groove 22, thereby lubricating and cooling the friction pair between the planetary gear 7 and the planetary gear shaft 2, improving the lubrication effect on the planetary gear 7 and the planetary gear shaft 2, and improving the performance and service life of the differential, transmission system and reduction gear box.

[0040] It should be noted that, since two planetary gears 7 are usually symmetrically arranged on the planetary gear shaft 2, two independent first oil grooves 22 can be respectively extended to the two gear mating parts 21 for lubrication and cooling, or the two ends of the same first oil groove 22 can be respectively extended to the two gear mating parts 21 for lubrication and cooling. At the same time, the number of the first oil grooves 22 can be one or more, and the shape of the first oil grooves 22 can be linear, curved, wavy or sawtooth, and the lubrication and cooling of the gear mating parts 21 can be achieved while ensuring the structural strength of the planetary gear shaft 2, which is not limited here.

[0041] In some embodiments of this application, please refer to Figure 2The first oil groove 22 is a linear groove arranged along the axial length of the planetary gear shaft 2, that is, the length of the first oil groove 22 is equal to the length of the planetary gear shaft 2, so that the first oil groove 22 can be directly formed by linear feed milling on the outer surface of the planetary gear shaft 2, and the manufacturing process is simple; in addition, the first oil groove 22 can also be connected to the first shaft hole 11, so that the lubricating oil can enter and exit the differential case 1 through the gap between the first oil groove 22 and the first shaft hole 11, and the gap between the first shaft hole 11 and the outer surface of the planetary gear shaft 2 can also be lubricated.

[0042] In some embodiments of this application, please refer to Figure 2 A plurality of first oil grooves 22 are sequentially arranged along the circumference of the planetary gear shaft 2, which can uniformly lubricate the friction pair of the planetary gear shaft 2 and the planetary gear 7 in the circumferential direction, thereby improving the lubrication and cooling effect between the planetary gear shaft 2 and the planetary gear 7 and avoiding local overheating.

[0043] It should be noted that, since most of the lubricating oil in the external oil pool of the differential enters the differential housing 1 from the differential housing window 17, it is preferred to set the opening of the first oil groove 22 toward the differential housing window 17 to facilitate the lubricating oil to enter the first oil groove 22. In some preferred embodiments of the present application, two first oil grooves 22 of the same length as the planetary gear shaft 2 are respectively provided on both sides of the planetary gear shaft 2, such as Figure 2 After the differential is assembled, the two first oil grooves 22 are respectively arranged toward the differential housing windows 17 on both sides of the differential housing 1, so that the first oil grooves 22 are directly opposite to the differential housing windows 17. When the lubricating oil enters the interior of the differential housing 1 from the differential housing windows 17, it can flow along the first oil grooves 22 to the two ends of the planetary gear shaft 2, thereby cooling and lubricating the friction pairs at the two ends of the planetary gear shaft 2; excess lubricating oil can flow out from the differential housing windows 17 or the gap between the first oil grooves 22 and the first shaft hole 11.

[0044] In some embodiments of this application, please refer to Figure 2 and Figure 3 Both ends of the planetary gear shaft 2 are provided with gear matching parts 21 for matching with the two planetary gears 7. A half-shaft avoidance part 23 is provided between the two gear matching parts 21 for avoiding the transmission half-shaft inserted in the half-shaft gear 6. The end of the transmission half-shaft can be extended out of the half-shaft gear 6, thereby increasing the connection area between the transmission half-shaft and the half-shaft gear 6 and improving the connection reliability between the transmission half-shaft and the half-shaft gear 6.

[0045] It should be noted that, in order to achieve the connection between the planetary gear shaft 2 and the differential housing 1, a first pin hole 19 is provided on the differential housing 1, and the axis of the first pin hole 19 is perpendicular to the axis of the first shaft hole 11. A second pin hole 24 is provided on the planetary gear shaft 2. The fixing pin 5 is inserted into the first pin hole 19 and the second pin hole 24, so that the fixed connection between the planetary gear shaft 2 and the differential housing 1 can be achieved.

[0046] During the operation of the differential, a portion of the lubricating oil enters the differential case 1 from the half-shaft assembly hole of the differential. However, the journal diameter of the half-shaft gear 6 in the prior art is larger than the diameter of the half-shaft assembly hole, which will block the lubricating oil entering from the half-shaft assembly hole, resulting in a limited amount of lubricating oil entering the differential case 1 through the half-shaft assembly hole, and the inside of the differential case 1 cannot be effectively lubricated.

[0047] In order to solve the above problems, in some embodiments of the present application, please refer to Figure 1 and Figure 3 , along the direction from outside to inside of the differential case 1, a second shaft hole 12 and a second oil groove 13 are sequentially provided, the second shaft hole 12 is used to insert the transmission half shaft, and the axis of the second shaft hole 12 is perpendicular to the axis of the first shaft hole 11, so as to facilitate the meshing transmission between the transmission half shaft, the half shaft gear 6 and the planetary gear 7. The second oil groove 13 is coaxially arranged with the second shaft hole 12, and the diameter of the second oil groove 13 is larger than the diameter of the second shaft hole 12, so that there is a preset gap in the radial direction between the cylindrical inner wall surface of the second oil groove 13 and the journal of the half shaft gear 6, so as to facilitate the lubricating oil to enter the inside of the differential case 1 through the second oil groove 13. Preferably, the preset gap is greater than 0.5 mm.

[0048] In the prior art, since the assembly clearance between the half-shaft assembly hole on the differential case and the transmission half-shaft is small, the amount of lubricating oil entering the second oil groove 13 and the interior of the differential case 1 through the half-shaft assembly hole is limited, and the half-shaft assembly hole of the differential case 1 and the interior of the differential case 1 cannot be effectively lubricated.

[0049] In order to solve the above problems, in some embodiments of the present application, please refer to Figure 1 and Figure 3, both sides of the differential housing 1 are provided with second shaft holes 12, which are used to insert the left and right transmission half shafts respectively. The inner wall of the second shaft hole 12 is provided with a spiral oil guide groove 121. When the differential is running, the lubricating oil can enter the second shaft hole 12 through the spiral oil guide groove 121, which can increase the amount of lubricating oil entering the second shaft hole 12, thereby increasing the amount of lubricating oil entering the inside of the differential housing 1 from the second oil hole 41 and the second oil groove 13, which is beneficial to lubricate the parts inside the differential housing 1. The spiral oil guide grooves 121 on both sides of the differential housing 1 rotate in opposite directions, so that when the differential housing 1 rotates, the lubricating oil in the external oil pool of the differential can be directed to the inside of the differential housing 1 through the spiral oil guide grooves 121 on both sides.

[0050] In some embodiments of this application, please refer to Figure 1 and Figure 3 The differential case 1 further includes an oil storage chamber 14 coaxially arranged with the second shaft hole 12. The oil storage chamber 14 is located between the second shaft hole 12 and the second oil groove 13. The oil storage chamber 14 has a cylindrical inner wall surface, and the diameter of the oil storage chamber 14 is between the diameter of the second oil groove 13 and the diameter of the second shaft hole 12, so that a stepped oil guide channel can be formed, so that a part of the lubricating oil flows through the spline matching part on the side gear 6 and then leaks into the internal cavity of the differential through the matching clearance, and another part of the lubricating oil enters the interior of the differential case 1 through the second oil groove 13, so as to facilitate lubrication of the friction surface between the side gear 6 and the inner wall of the differential case 1.

[0051] Since the side gears 6 and the planetary gears 7 are arranged inside the differential case 1, during the operation of the differential, relative friction will occur between the side gears 6 or the planetary gears 7 and the inner wall of the differential case 1. If the friction parts cannot be lubricated, the performance and service life of the side gears 6, the planetary gears 7 and the differential case 1 will be affected.

[0052] In order to solve the above problems, in some embodiments of the present application, please refer to Figure 1 , Figure 3 and Figure 4 The inner wall of the differential case 1 is provided with a side gear mating surface 15 and a planet gear mating surface 16; a third oil groove 151 is provided on the side gear mating surface 15, and the second oil groove 13 is connected to the third oil groove 151, so that the lubricating oil in the second oil groove 13 can enter the third oil groove 151, thereby lubricating and cooling the side gear mating surface 15 on the differential case 1. A fourth oil groove is provided on the planet gear mating surface 16, and the first shaft hole 11, the first oil groove 22 and the fourth oil groove are connected, so that the lubricating oil in the first oil groove 22 can flow to the planet gear mating surface 16 through the fourth oil groove, thereby lubricating and cooling the planet gear mating surface 16.

[0053] It should be noted that the number of the third oil grooves 151 is preferably multiple, and the multiple third oil grooves 151 can be arranged in a cross shape, radially arranged, etc. on the side gear mating surface 15, so as to facilitate the radial flow of lubricating oil on the side gear mating surface 15, so that the entire side gear mating surface 15 is effectively lubricated. In a preferred embodiment of the present application, please refer to Figure 4 The plurality of third oil grooves 151 are centrally symmetrically arranged with the axis of the second shaft hole 12 as the center, so that the lubricating oil can centrifugally move along the third oil grooves 151 when the differential housing 1 rotates, thereby allowing the lubricating oil to flow through the entire half-shaft gear mating surface 15.

[0054] It should be noted that the fourth oil groove may be arranged in a manner similar to the third oil groove 151 . It is preferred that a plurality of fourth oil grooves are arranged in a cross shape on the planetary gear mating surface 16 to facilitate the processing of the fourth oil grooves.

[0055] In some embodiments of this application, please refer to Figure 1 and Figure 4 An annular fifth oil groove 18 is also provided inside the differential housing 1, and the fifth oil groove 18 is connected to the third oil groove 151, so that excess lubricating oil in the third oil groove 151 can flow into the fifth oil groove 18 along the third oil groove 151, and then leak into the interior of the differential housing 1 through the fifth oil groove 18.

[0056] In some embodiments of this application, please refer to Figure 3 A first liner 3 is provided on the half-shaft gear mating surface 15, and a second liner 4 is provided on the planetary gear mating surface 16, which can be used to reduce the wear of the half-shaft gear 6 and the planetary gear 7, and can also play a role in buffering and shock absorption, which can help to extend the service life of the half-shaft gear 6 and the planetary gear 7.

[0057] In some embodiments of this application, please refer to Figure 5 and Figure 6 , the first gasket 3 and the second gasket 4 are both provided with a plurality of oil holes, so that the lubricating oil can enter the gap between the gasket and the inner wall of the differential case 1 and the gap between the gasket and the gear through the oil holes, so as to achieve effective lubrication of each component. Specifically, the first gasket 3 is provided with a plurality of first oil holes 31, through which the lubricating oil can enter the gap between the half-shaft gear mating surface 15 and the first gasket 3, and can also enter the gap between the first gasket 3 and the half-shaft gear 6. The second gasket 4 is provided with a plurality of second oil holes 41, through which the lubricating oil can enter the gap between the planetary gear mating surface 16 and the second gasket 4, and can also enter the gap between the second gasket 4 and the planetary gear 7 through the second oil holes 41.

[0058] In the above embodiment, if the distances between the multiple oil holes and the axis of the gasket are the same, the lubricating oil will be concentrated in the middle annular area of ​​the gasket, while the amount of lubricating oil in the inner and outer annular areas is limited, which may cause local overheating.

[0059] In order to solve the above problems, in some embodiments of the present application, please refer to Figure 5 and Figure 6 On the first liner 3 or the second liner 4, the distances between the multiple oil holes and the liner axis vary periodically, so that the multiple oil holes and the liner axis are distributed non-equidistantly, so that the lubricating oil can be distributed in various areas of different diameters in the liner through the oil holes, thereby increasing the lubrication area and avoiding local overheating.

[0060] It should be noted that the periodic change refers to the alternating change of increasing and decreasing distances between the multiple oil holes arranged in sequence along the circumference of the liner and the liner axis, such as Figure 5 and Figure 6 In some preferred embodiments of the present application, a plurality of oil holes are arranged on the gasket in a square or rhombus shape, and the center of the square or rhombus is on the axis of the gasket.

[0061] In some embodiments of this application, please refer to Figure 3 The differential also includes a half-shaft gear 6 and a planetary gear 7 arranged inside the differential housing 1. The transmission half-shaft is inserted in the half-shaft gear 6, and the planetary gear shaft 2 is inserted in the planetary gear 7. Through the meshing of the half-shaft gear 6 and the planetary gear 7, the differential rotation of the transmission half-shafts on both sides is realized.

[0062] This embodiment also proposes a car, including the differential described in the above embodiment. Preferably, the car is an electric drive car, and the differential is arranged in an electric drive reduction box system, which can achieve efficient lubrication with a limited amount of lubricating oil.

[0063] See also Figures 1 to 6 In some embodiments of the present application, the lubrication process of the differential is as follows:

[0064] Step 1: The differential starts to operate, the differential housing 1 rotates, and the lubricating oil in the oil pool outside the differential is stirred up.

[0065] Step 2: On the one hand, the lubricating oil enters the inside of the differential case 1 from the differential case window 17, and part of the lubricating oil splashes onto the tooth surfaces of the planetary gear 7 and the half-shaft gear 6 to lubricate the meshing tooth surfaces as the differential case 1 and the internal components operate. Another part of the lubricating oil splashes onto the outer surface of the planetary gear shaft 2, and part of the lubricating oil splashed onto the planetary gear shaft 2 first flows to the gear mating portion 21 through the first oil groove 22 to lubricate and cool the friction pair between the planetary gear shaft 2 and the planetary gear 7; and then flows along the first oil groove 22 to the gap between the planetary gear 7 and the second liner 4, and the gap between the second liner 4 and the planetary gear mating surface 16 for lubrication and cooling.

[0066] On the other hand, the lubricating oil enters the oil storage chamber 14 along the spiral oil guide groove 121 in the second shaft hole 12, and part of the lubricating oil enters the spline mating part of the half-shaft gear 6, and then leaks into the inside of the differential case 1 through the fitting clearance; another part of the lubricating oil enters the third oil groove 151 through the second oil groove 13 to lubricate the half-shaft gear mating surface 15, and part of the lubricating oil on the half-shaft gear mating surface 15 enters the gap between the first liner 3 and the half-shaft gear 6 through the oil hole of the first liner 3, lubricates and cools the friction surface between the first liner 3 and the half-shaft gear 6, and then leaks into the inside of the differential case 1 through the fitting clearance; the remaining lubricating oil on the half-shaft gear mating surface 15 flows into the fifth oil groove 18 along the third oil groove 151, and finally leaks into the inside of the differential case 1.

[0067] Step 3: The lubricating oil leaked into the internal cavity of the differential case 1 partially flows back to the external oil pool of the differential through the differential case window 17, and partially splashes onto the tooth surfaces of the planetary gears 7 and the half-shaft gears 6 to lubricate the meshing tooth surfaces. The remaining part passes through the first oil groove 22 on the planetary gear shaft 2 to lubricate the mating surfaces of the planetary gear 7 and the planetary gear shaft 2, and then flows back to the external oil pool of the differential through the first shaft hole 11.

[0068] The present application provides a first oil groove 22 on the outer surface of the planetary gear shaft 2, so as to lubricate and cool the friction pair between the planetary gear shaft 2 and the planetary gear 7, thereby optimizing the lubrication of the fitting point between the planetary gear shaft 2 and the planetary gear 7; combined with the second oil groove 13, the oil storage cavity 14, the third oil groove 151, the fourth oil groove, the fifth oil groove 18 and the oil holes on the gasket, the limited amount of lubricating oil can be fully utilized to achieve the lubrication and cooling of the friction pairs between the components, thereby ensuring the functional reliability of the differential assembly and improving the life of the electric drive reduction box system.

[0069] The above embodiments are only preferred embodiments for fully illustrating the present application, and the protection scope of the present application is not limited thereto. Any equivalent substitution or change made by a person skilled in the art based on the present application is within the protection scope of the present application.

Claims

1. A differential, characterized in that: include: A differential housing (1), wherein the differential housing (1) has a first shaft hole (11); A planetary gear shaft (2), the planetary gear shaft (2) being inserted into the first shaft hole (11), the planetary gear shaft (2) having a gear matching portion (21), and the outer surface of the planetary gear shaft (2) having a first oil groove (22) extending to the gear matching portion (21); The two ends of the planetary gear shaft (2) are each provided with the gear matching portion (21), and a half-shaft avoidance portion (23) is provided between the two gear matching portions (21).

2. The differential according to claim 1, characterized in that: The first oil groove (22) is arranged along the axial length of the planetary gear shaft (2); and a plurality of the first oil grooves (22) are arranged in sequence along the circumferential direction of the planetary gear shaft (2).

3. The differential according to claim 1 or 2, characterized in that: A second shaft hole (12) and a second oil groove (13) are sequentially arranged along the direction from the outside to the inside of the differential housing (1); the axis of the second shaft hole (12) is perpendicular to the axis of the first shaft hole (11); the second oil groove (13) is coaxially arranged with the second shaft hole (12); and the diameter of the second oil groove (13) is larger than the diameter of the second shaft hole (12).

4. The differential according to claim 3, characterized in that: Second shaft holes (12) are provided on both sides of the differential housing (1), spiral oil guide grooves (121) are provided on the inner wall of the second shaft hole (12), and the spiral oil guide grooves (121) on both sides of the differential housing (1) have opposite rotation directions.

5. The differential according to claim 3, characterized in that: The differential case (1) further comprises an oil storage chamber (14) coaxially arranged with the second shaft hole (12); the oil storage chamber (14) is located between the second shaft hole (12) and the second oil groove (13); the diameter of the oil storage chamber (14) is between the diameter of the second oil groove (13) and the diameter of the second shaft hole (12).

6. The differential according to claim 3, characterized in that: The inner wall of the differential housing (1) is provided with a half-shaft gear mating surface (15) and a planetary gear mating surface (16); a third oil groove (151) is provided on the half-shaft gear mating surface (15), and the second oil groove (13) is connected to the third oil groove (151); a fourth oil groove is provided on the planetary gear mating surface (16), and the first shaft hole (11), the first oil groove (22) and the fourth oil groove are connected.

7. The differential according to claim 6, characterized in that: A first liner (3) is provided on the half-shaft gear mating surface (15), and a second liner (4) is provided on the planetary gear mating surface (16); and a plurality of oil holes are provided on the first liner (3) and the second liner (4).

8. The differential according to claim 7, characterized in that: On the first gasket (3) or the second gasket (4), the distances between the plurality of oil holes and the gasket axis vary periodically.

9. A car, characterized in that: Comprising a differential as claimed in any one of claims 1 to 8.

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