Axle drive for a motor vehicle

Abstract

The invention relates to an axle drive (1) for a motor vehicle, comprising a rotating differential gear (2) and at least one rotating axle shaft (3) coupled thereto, wherein the differential gear (2) has a differential housing (4) in which an oil channel (5) is integrated, wherein a mechanical or electric oil pump is arranged which supplies a constant or adjustable volume of oil to the differential gear (2) via a supply line, wherein the oil supply is provided via an annular gap (6) between the axle shaft (3) and the differential housing (4), wherein an opening of the shaped tube (7) is arranged in an upper region of the annular gap (6) and is positioned so deep in the annular gap (6) that the oil can flow into the interior of the differential gear (2) in a controlled manner according to an existing volume flow rate.excess oil drains off at the bottom of the annular gap (6) or through any openings that may be present in the differential housing (4).

Description

[0001] The invention relates to an axle drive for a motor vehicle according to the preamble of claim 1.

[0002] Common forms of differential gear lubrication include passive lubrication combined with an oil supply for the entire axle drive. Encapsulated differential gears are also known, which have their own lubricant supply, decoupled from the rest of the axle drive.

[0003] US 4,352,301 A describes a small pump connected outside the differential housing of an axle assembly, which draws oil from the housing and pumps it through an external filter. This cools and cleans the oil, allowing it to be directed to the outer bearing areas of the halfshafts for lubrication. The oil flows by gravity through the axle housing back to the differential housing. If desired, an oil cooler can be integrated into the system.

[0004] The invention is based on the object of specifying a novel axle drive for a motor vehicle.

[0005] The object is achieved according to the invention by an axle drive for a motor vehicle having the features of claim 1.

[0006] Advantageous embodiments of the invention are the subject of the subclaims.

[0007] An axle drive for a motor vehicle is proposed, comprising a differential gear that rotates during operation and at least one axle shaft coupled to it that rotates during operation, wherein the differential gear has a differential housing into which an oil channel is integrated, wherein a mechanical or electric oil pump is arranged that feeds a constant or adjustable volume of oil into the differential gear via a supply line, wherein the oil is supplied via an annular gap between the axle shaft and the differential housing. According to the invention, an opening of the shaped tube is arranged in an upper region of the annular gap and positioned so deep in the annular gap that the oil can flow into the interior of the differential gear in a targeted manner in accordance with an existing volume flow, wherein excess oil drains off at the underside of the annular gap or through any openings present in the differential housing.

[0008] The solution according to the invention enables the gearing and the plain or roller bearings of differential gears in axle drives to be specifically supplied with the required amount of oil for operation, despite limited installation space. Furthermore, the present invention enables the differential gear to operate thanks to the targeted and adjustable lubricant quantity even when the lubricant used belongs to a viscosity class that has limited lubricating properties for differential gears. This is necessary, for example, when a specific oil viscosity and / or oil additives are required for a shared oil supply with other transmission components.Active lubrication, through the possible, significantly higher oil flow in the differential gear, solves in particular the problem that insufficient lubrication of the differential drive components can lead to unacceptable temperature increases and / or increased wear of the differential drive components.

[0009] In contrast to passive lubrication, where oil never reaches the differential gear or only reaches the differential in an undefined quantity, active lubrication provides a precisely defined quantity of oil. A deliberately excessive oil quantity serves to cool the oil, as the heat generated by the drive components in the differential gear is constantly dissipated into the larger volume of the axle drive for cooling due to the excess oil. Furthermore, a deliberately excessive supply of lubricating oil in the differential gear serves to optimize lubrication, even in hard-to-reach areas inside the differential gear. The excess oil can also compensate for an oil type that is not perfectly matched to the differential gear by using a large amount of oil to offset the loss in lubrication, thus still achieving the service life. This is particularly the case when multiple transmission components have the same oil supply.

[0010] Embodiments of the invention are explained in more detail below with reference to a drawing.

[0011] It shows: Fig. 1 a schematic partially sectioned detailed view of an axle drive of a motor vehicle.

[0012] The only Fig. Figure 1 is a schematic, partially sectioned, detailed view of an axle drive 1 of a motor vehicle, wherein the axle drive 1 comprises a differential gear 2 that rotates during operation and at least one axle shaft 3 coupled thereto that rotates during operation. The differential gear 2 comprises a differential housing 4 into which an oil channel 5 is integrated.

[0013] According to the present invention, a mechanical or electric oil pump (not shown) is integrated into the oil supply of the axle drive 1, which pump feeds a constant or adjustable oil volume into the differential gear 2 via a suitable supply line, in particular a shaped pipe 7 made of metal or plastic.

[0014] The oil supply takes place via an annular gap 6 between the axle shaft 3 and the differential housing 4, wherein the annular gap 6 is adapted to a diameter of the shaped tube 7.

[0015] In particular, an opening of the shaped tube 7 is arranged in an upper region of the annular gap 6 between the axle shaft 3 and the differential housing 4 and is positioned so deep within the annular gap 6 that the oil can flow into the interior of the differential gear 2 in a targeted manner according to the available volume flow. The differential gear 2 is thereby flooded with the oil.

[0016] Excess oil flows back into the axle drive 1 at the bottom of the annular gap 6 or through any openings in the differential housing 4. This creates oil circulation through the differential gear 2. List of reference symbols 1 axle drive 2 differential gears 3 axle shaft 4 differential housing 5 Oil channel 6 Annular gap 7 shaped pipe QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] US 4,352,301 A

[0003]

Claims

[1] Axle drive (1) for a motor vehicle, comprising a differential gear (2) which rotates during operation and at least one axle shaft (3) which is coupled thereto and rotates during operation, wherein the differential gear (2) has a differential housing (4) into which an oil channel (5) is integrated, wherein a mechanical or electrical oil pump is arranged which directs a constant or adjustable oil volume via a supply line into the differential gear (2), wherein the oil supply takes place via an annular gap (6) between the axle shaft (3) and the differential housing (4), characterized by that an opening of the shaped tube (7) is arranged in an upper region of the annular gap (6) and is positioned so deep in the annular gap (6) that the oil can flow into the interior of the differential gear (2) in a targeted manner in accordance with an existing volume flow, with excess oil running off at the underside of the annular gap (6) or through any openings present in the differential housing (4). [2] Axle drive (1) according to claim 1, characterized by that the supply line is formed as a shaped pipe (7) made of metal or plastic. [3] Axle drive (1) according to claim 1 or 2, characterized by that the annular gap (6) is adapted to a diameter of the shaped tube (7).

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