Bevel gear differential for a vehicle and vehicle with such a bevel gear differential

Abstract

The invention relates to a bevel gear differential (1) for a vehicle (100), comprising • a differential basket (2) designed as a differential input shaft, • at least two compensating bevel gears (3) which are rotatably mounted in the differential basket (2), • two output bevel gears (5) which are non-rotatably connected to a respective output shaft (6) and each engage in tooth mesh with the at least two compensating bevel gears (3), • wherein at least one through-hole (7) for each compensating bevel gear (3) forms a channel for the passage of lubricant into the differential basket (2), • wherein the at least one through-hole (7) is designed to guide lubricant from a lubricant transfer point (8) located on the outside of the differential basket (2) to a contact surface (9) of the respective compensating bevel gear (3) on the differential basket (2).

Description

[0001] The invention relates to a bevel gear differential for a vehicle. Furthermore, the invention relates to a vehicle with such a bevel gear differential and a vehicle axle with such a bevel gear differential.

[0002] In generally known bevel gear differentials, a radial thrust washer is arranged between the compensating bevel gears, which are rotatably mounted in the differential basket, and the differential basket. This thrust washer is designed as a sliding bearing point and is intended to achieve low-wear relative movement between the compensating bevel gears and the differential basket when cornering.

[0003] For example, EP 0 343 146 A2 discloses a differential gear comprising a differential housing rotatably and driveably mounted in a gearbox housing for receiving meshing differential and output gears, wherein the gearbox housing forms an oil chamber and the differential housing, which is provided with oil passage holes on both sides of the central plane defined by the differential gear axes, is immersed in the oil sump of the oil chamber. In order to ensure sufficient compensatory lubrication with minimal construction effort, the oil passage holes on one side of the differential housing are covered externally by a rotationally symmetrical centrifugal cup coaxial to the axis of rotation of the differential housing. This centrifugal cup, which widens at least partially towards the central plane of the differential housing, connects radially outside the oil passage holes, close to the differential housing, and has an oil inlet opening radially inside the oil passage holes.

[0004] From publication JP H08-3740 Y2, an axle differential for motor vehicles is known in which the differential housing, which accommodates the differential mechanism, is rotatably mounted and lubricating oil is supplied around the differential housing. The differential housing has an oil bore on its end face that connects the inner and outer parts of the differential housing.

[0005] CN 108 194 625 A discloses a method for arranging oil channels in the housing of the drive axle differential, wherein several oil channels are arranged on the left housing half of the differential, connecting the interior and exterior of the differential housing. The inlet of the oil channels is located near the outer edge of the reinforcing rib on the left housing half to ensure that lubricating oil from outside the differential housing can enter the housing interior via the oil channels at both low and high speeds. Simultaneously, at high speeds, excess lubricating oil from inside the differential housing can flow outwards through the oil passages in the left and right housing halves. This allows for a circulating flow of lubricating oil between the inside and outside of the differential housing via the oil channels and the oil passages in the left and right housing halves, which promotes heat dissipation and the removal of contaminants from inside the differential housing.

[0006] The object of the present invention is to provide an alternative bevel gear differential for a vehicle. In particular, the bevel gear differential should be simple and inexpensive to manufacture. This object is achieved by the features of independent claim 1. Advantageous embodiments are the subject of the dependent claims, the following description, and the figures.

[0007] According to a first aspect, a bevel gear differential for a vehicle is provided, comprising a differential basket designed as a differential input shaft, at least two compensating bevel gears rotatably mounted in the differential basket via differential bolts, two output bevel gears, each of which is in tooth mesh with the at least two compensating bevel gears and is designed to be rotationally fixed to a respective output shaft, wherein at least one through-bore for each compensating bevel gear forms a channel for the passage of lubricant in the differential basket, wherein the at least one through-bore is designed to guide lubricant from a lubricant transfer point located on the outside of the differential basket to a contact surface of the respective compensating bevel gear with the differential basket.

[0008] A bevel gear differential for a passenger car, for example, comprises two differential gears arranged at an angle of 180° to each other in the differential housing. In contrast, a bevel gear differential for a construction machine, bus, or truck, for example, comprises four differential gears arranged at an angle of 90° to each other in the differential housing. The respective differential gears rotate around their own axis within the differential housing when cornering. For example, each output bevel gear is non-rotatably connected to a corresponding output shaft via a splined connection. The output shafts are designed to be effectively connected to the vehicle's drive wheels. For example, the drive power supplied to the bevel gear differential is distributed to the output shafts and transmitted to the drive wheels of the output axle. The respective output shaft can be connected directly or indirectly.be indirectly connected to the corresponding vehicle wheel via a joint, a driveshaft and / or a wheel hub.

[0009] The differential housing is designed to be effectively connected to a drive motor. For example, the differential housing is effectively connected to a transmission output shaft of a gearbox located between the drive motor and the bevel gear differential. In particular, the differential housing has a circumferential toothing that meshes with teeth on the transmission output shaft to transmit the drive power from the drive motor to the bevel gear differential. Alternatively, the circumferential toothing on the differential housing meshes with teeth on a rotor shaft of a drive motor designed as an electric machine.

[0010] The at least one through-hole in the differential carrier is designed such that the lubricant is guided from a lubricant transfer point through the differential carrier to a contact surface of the respective compensating bevel gear inside the differential carrier. Because the lubricant is guided directly to the contact surface of the respective compensating bevel gear with the differential carrier, the radial thrust washers can be omitted, making the bevel gear differential simpler and more cost-effective to manufacture. Furthermore, the grooves on the differential carrier, which are designed to prevent the thrust washers from rotating, are also eliminated.

[0011] If the bevel gear differential has two compensating bevel gears, at least two through-holes are provided in the differential housing. In other words, exactly one through-hole is provided for each of the two compensating bevel gears. If the bevel gear differential has four compensating bevel gears, at least four through-holes are provided in the differential housing. In other words, exactly one through-hole is provided for each of the two compensating bevel gears.

[0012] In particular, a gap is formed, at least partially and especially temporarily, between the respective differential bevel gear and the differential carrier. This gap is filled or wetted with lubricant from the vehicle's pressurized lubrication system via the respective through-hole. According to one embodiment, the contact surface of the respective differential bevel gear with the differential carrier has a wear-reducing coating. For example, each differential bevel gear has a protective layer in the area of ​​the contact surface with the differential carrier, i.e., at least on the spherical surface, which reduces friction and wear. For example, the wear-reducing coating is produced by phosphating or additive treatment of the spherical surface on the respective differential bevel gear. In phosphating, a so-called conversion layer of firmly adhering metal phosphates is formed by chemical reactions of the metallic surface with aqueous phosphate solutions.

[0013] According to one embodiment, the contact surface of each compensating bevel gear with the differential carrier has at least one groove for distributing the lubricant between the respective compensating bevel gear and the differential carrier. For example, each compensating bevel gear has at least one groove or several grooves in the area of ​​the contact surface with the differential carrier, i.e., at least on the spherical surface, which receive the lubricant and, when the compensating bevel gears rotate, distribute it across the contact surface with the differential carrier, particularly in the respective gap between the respective compensating bevel gear and the differential carrier. For example, a spiral or helical groove is formed in the contact surface of the respective compensating bevel gear with the differential carrier. Alternatively, several radially extending grooves are formed in the contact surface of the respective compensating bevel gear with the differential carrier.In this context, a groove is understood to be a recess in the contact surface of the respective compensating bevel gear to the differential basket.

[0014] According to the invention, the lubricant transfer point is designed as a circumferential annular channel between the differential carrier and a housing, wherein the annular channel is fluidically sealed by means of two sealing rings that bear against the differential carrier and the housing. The circumferential annular channel enables the supply of lubricant to several circumferentially distributed through-bores. For example, the circumferential annular channel can be easily formed by fluidic sealing using the two sealing rings. In particular, the two sealing rings are designed as dynamic sealing rings.

[0015] According to one embodiment, at least one of the channels in the differential carrier is designed to supply lubricant to a contact surface of the respective output bevel gear with the differential carrier. Thus, the through-holes forming the lubricant channels supply lubricant not only to the contact points of the differential bevel gears with the differential carrier, but also to the contact points of the output bevel gears with the differential carrier. This eliminates the need for two axial thrust washers located between the respective output bevel gear and the differential carrier. For example, the channel leading to the contact surface of the respective output bevel gear on the differential carrier is formed by a maximum of three through-holes in the differential carrier. Preferably, a sealing element for fluidic sealing is arranged in at least one through-hole in the differential carrier.For example, a channel with three through-holes incorporates two sealing elements for fluidic sealing. The sealing element can be a plug or screw and is at least partially inserted into the respective through-hole. By forming the channel in the differential housing using through-holes, the manufacturing of the bevel gear differential is simplified, thereby reducing production costs.

[0016] According to one embodiment, the lubricant transfer point is configured to receive lubricant via a supply channel from a lubrication system for lubricating other components of a vehicle axle. In particular, the supply channel is formed in the housing of the bevel gear differential and connects the lubricant transfer point, especially the circumferential annular channel, to the vehicle's lubrication system.

[0017] According to a second aspect, a vehicle axle is provided with a lubrication system and a bevel gear differential according to the first aspect. According to a third aspect, a vehicle is provided with at least one bevel gear differential according to the first aspect. The above definitions, as well as descriptions of the technical effects, advantages, and advantageous embodiments of the bevel gear differential according to the invention, also apply mutatis mutandis to the vehicle axle and the vehicle according to the invention. The vehicle is preferably a motor vehicle or commercial vehicle. For example, the vehicle can be designed as a passenger car, truck, bus, or construction machine. In particular, the vehicle axle is designed as a drive axle and further comprises a drive motor, in particular an electric motor, and optionally a transmission arranged in the power flow between the electric motor and the bevel gear differential.The lubrication system of the vehicle axle is also specifically designed to cool and lubricate the electric motor and the gearbox.

[0018] Advantageous embodiments of the invention, which is explained below, are illustrated in the drawings, wherein identical or similar elements are designated with the same reference numeral. They show: Fig. 1 a highly simplified schematic representation of a vehicle, Fig. 2 a highly simplified schematic representation of a vehicle axle with a bevel gear differential, Fig. 3 a schematic sectional view of a section of a bevel gear differential according to a first embodiment and Fig. 4 a schematic sectional view of a section of a bevel gear differential according to a second embodiment.

[0019] Fig. Figure 1 shows a vehicle 100 with a first axle 30 with two wheels 50 and a second axle 31 with two wheels 50. In this case, the first axle 30 is configured as the rear drive axle of the vehicle 100 and comprises an electric motor 40, which is configured to generate drive power, and a bevel gear differential 1, which is configured to distribute the drive power to the two wheels 50 of the axle 30. Furthermore, the axle 30 has a lubrication system 20, which is configured to cool and lubricate the electric motor 40 and the bevel gear differential 1. In this case, the vehicle 100 is configured as an electric passenger car.

[0020] Fig. Figure 2 shows a vehicle axle 30 with a bevel gear differential 1, which is effectively connected to an electric motor 40 for drive purposes. The electric motor 40 and the bevel gear differential 1 are connected to a lubrication system 20, with this connection indicated by a respective dashed line. The lubrication system 20 delivers a lubricant through the electric motor 40 and the bevel gear differential 1 by means of pressure. The bevel gear differential 1 comprises a differential carrier 2, which is designed as the differential input shaft, two compensating bevel gears 3, which are rotatably mounted in the differential carrier 2 via planetary gear pins 4, and two output bevel gears 5, which are each in mesh with the two compensating bevel gears 3 and are non-rotatably connected to a respective output shaft 6.The bevel gear differential 1 is driven via the differential carrier 2, which is effectively connected to a rotor shaft 17 of the electric machine 40. The output of the bevel gear differential 1 is provided via the two output shafts 6, which are designed to be effectively connected to the vehicle's drive wheels, with the connection to the respective drive wheel indicated by an arrow on the respective output shaft 6. The drive power supplied to the bevel gear differential 1 is distributed to the two output shafts 6 and transmitted to the drive wheels of the vehicle axle 30.

[0021] In Fig. Figure 3 is a section of the bevel gear differential 1 according to Fig. Figure 2 shows the lubrication system 20 in a highly schematic way, indicated by a rectangle. A through-hole 7 is formed in the differential carrier 2 for each differential bevel gear 3, which is rotatably mounted in the differential carrier 2 via a differential pin 4. Each through-hole 7 forms a channel for the passage of lubricant. If the bevel gear differential 1 has two differential bevel gears 3, two through-holes 7 are formed in the differential carrier 2. If the bevel gear differential 1 has four differential bevel gears 3, four through-holes 7 are formed in the differential carrier 2. Each through-hole 7 is designed to guide lubricant from a lubricant transfer point 8, located on the outside of the differential carrier 2, to a contact surface 9 of the respective differential bevel gear 3 inside the differential carrier 2.The lubricant transfer point 8 is supplied with lubricant from the lubrication system 20 via a supply channel 16 formed in a housing 12. In this design, the lubricant transfer point 8 is configured as a circumferential annular channel between the differential carrier 2 and the housing 12, the annular channel being fluidically sealed by two dynamic sealing rings 13 that bear against the differential carrier 2 and the housing 12. The differential carrier 2 is configured as a differential input shaft and is rotatably mounted in the housing 12 via a bearing 19. The lubricant is pressurized and forced into the circumferential annular channel and conveyed through the through-bores 7 in the differential carrier 2 into a gap between the spherical contact surface 9 of the respective differential bevel gear 3 and the differential carrier 2.The spherical surface of each compensating bevel gear 3 has a spiral groove 11 for distributing the lubricant between the respective compensating bevel gear 3 and the differential carrier 2. By introducing lubricant onto the contact surface 9 of the respective compensating bevel gear 3 with the differential carrier 2, a radial thrust washer between the contact surface 9 of the respective compensating bevel gear 3 and the differential carrier 2 can be eliminated. An axial thrust washer 18 is arranged on a contact surface 14 of the respective output bevel gear 5 with the differential carrier 2.

[0022] Fig. Figure 4 shows a second embodiment of the bevel gear differential 1. The second embodiment of the bevel gear differential 1 corresponds essentially to the first embodiment of the bevel gear differential 1. Only the differences between the two bevel gear differentials 1 are described below. Firstly, the axial thrust washer on the contact surface 14 of the respective output bevel gear 5 with the differential carrier 2 has been omitted. Secondly, the channels have been enlarged by additional through-holes 7 in the differential carrier 2 to supply lubricant to the contact surface 14 of the respective output bevel gear 5 with the differential carrier 2. This eliminates the need for the axial thrust washers. In this case, the respective channel consists of three through-holes 7 in the differential carrier 2.In other words, three through-holes 7 each form a channel for guiding lubricant to the contact surface 9 of the respective compensating bevel gear 3 with the differential carrier 2 and to the contact surface 14 of the respective output bevel gear 5 with the differential carrier 2. Two sealing elements 15 are arranged in two of the three through-holes 7 in the differential carrier 2 for fluidic sealing. This ensures that the lubricant is only directed to the contact surface 9 of the respective compensating bevel gear 3 with the differential carrier 2 and to the contact surface 14 of the respective output bevel gear 5 with the differential carrier 2. Furthermore, the contact surface 9 of the respective compensating bevel gear 3 with the differential carrier 2 does not have a groove, but rather a wear-reducing coating 10, for example by phosphating the spherical surface of the respective compensating bevel gear 3. Otherwise, the first embodiment of the bevel gear differential 1 according to [reference missing] applies. Fig.3. Referenced. Reference sign 1 bevel gear differential 2 Differential basket 3 Compensating bevel gear 4 differential bolts 5 Output bevel gear 6 Output shaft 7 through holes 8 Lubricant transfer point 9 Contact surface of the respective compensating bevel gear 10 coating 11 Nut 12 cases 13 Sealing ring 14 Contact surface of the output bevel gear 15 locking element 16 Supply channel 17 Rotor shaft 18 axial thrust washer 19 warehouses 20 Lubrication system 30 vehicle axle 31 vehicle axle 40 electric machine 50 wheel 100 vehicles

Claims

[1] Bevel gear differential (1) for a vehicle (100), comprising • a differential basket (2) designed as a differential input shaft, • at least two compensating bevel gears (3) which are rotatably mounted in the differential basket (2), • two output bevel gears (5) which are non-rotatably connected to a respective output shaft (6) and each engage in tooth mesh with the at least two compensating bevel gears (3), • wherein at least one through-hole (7) for each compensating bevel gear (3) forms a channel for the passage of lubricant into the differential basket (2), • wherein the at least one through-hole (7) is designed to guide lubricant from a lubricant transfer point (8) located on the outside of the differential basket (2) to a contact surface (9) of the respective compensating bevel gear (3) on the differential basket (2), • wherein the lubricant transfer point (8) is designed as a circumferential annular channel between the differential basket (2) and a housing (12), wherein the annular channel is fluidically sealed via two sealing rings (13) which come into contact with the differential basket (2) and the housing (12). [2] Bevel gear differential (1) according to claim 1, wherein the contact surface (9) of the respective compensating bevel gear (3) to the differential basket (2) has a wear-reducing coating (10). [3] Bevel gear differential (1) according to one of the preceding claims, wherein the contact surface (9) of the respective compensating bevel gear (3) on the differential basket (2) has at least one groove (11) for distributing the lubricant between the respective compensating bevel gear (3) and the differential basket (2). [4] Bevel gear differential (1) according to one of the preceding claims, wherein at least one of the channels in the differential basket (2) is designed for the passage of lubricant to a contact surface (14) of the respective output bevel gear (5) on the differential basket (2). [5] Bevel gear differential (1) according to one of the preceding claims, wherein at least one of the channels for the passage of lubricant is formed from a maximum of three through holes (7) in the differential basket (2). [6] Bevel gear differential (1) according to claim 5, wherein a sealing element (15) for fluidic sealing is arranged in at least one through-hole (7) in the differential basket (2). [7] Bevel gear differential (1) according to one of the preceding claims, wherein the lubricant transfer point (8) is configured to be supplied with lubricant via a supply channel (16) from a lubricant system (20) for the lubrication of further components of a vehicle axle (30). [8] Vehicle axle (30) comprising a lubrication system (20) and a bevel gear differential (1) according to any of the preceding claims. [9] Vehicle (100) with at least one bevel gear differential (1) according to any one of claims 1 to 7.

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