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DE-102024210836-A1 - Drive system for a motor vehicle

DE102024210836A1DE 102024210836 A1DE102024210836 A1DE 102024210836A1DE-102024210836-A1

Abstract

A drive unit (600) for a motor vehicle (105) comprises a machine housing section (300) for accommodating an electric machine (115) and a transmission housing section (305) for accommodating a transmission (130), as well as a hydraulic system (135) for cooling the electric machine (115) and/or lubricating the transmission (130), wherein an electric machine sump (380) is formed in the machine housing section (300) below the electric machine (115), in which the operating medium introduced for cooling can collect, and within which a first suction point (310) is also formed, which is hydraulically connected to a first suction line (225) of a first pump (201) of the hydraulic system (135) for cooling and/or lubricating thermal consumers. In this arrangement, at least one connecting channel (330) for the hydraulic connection of the winding head cooling unit (320) of the electric machine (115) and a gear compartment (335) of the gear housing section (305) is formed between the winding head cooling unit (320) of the electric machine (115) and the gear compartment (335), wherein a cooling and/or lubricating medium received in the gear compartment (335) can be drawn off at least indirectly to the first suction point (310) via at least one bypass (350) in the machine housing section (300). According to the invention, the hydraulic system (135) comprises at least one closing unit (601, 602) by means of which the connecting channel (330) can be closed when a lateral acceleration acts on the drive unit (600) and exceeds a certain maximum value.

Inventors

  • Tobias Zürn
  • Arthur Strehlau

Assignees

  • ZF FRIEDRICHSHAFEN AG

Dates

Publication Date
20260513
Application Date
20241112

Claims (16)

  1. Drive unit (100, 600) for a motor vehicle (105), comprising a machine housing section (300) with an electric machine (115) and a transmission housing section (305) with a transmission (130), as well as a hydraulic system (135) for cooling and/or lubricating thermal and/or mechanical consumers in the machine housing section (300) and in the transmission housing section (305), wherein an electric machine sump (380) is formed in the machine housing section (300) below the electric machine (115), in which the operating medium introduced for cooling can collect, and within which a first suction point (310) is also formed, which is hydraulically connected to a first suction line (225) of a first pump (201) of the hydraulic system (135) for cooling and/or lubricating thermal consumers, wherein a winding head cooling (320) of the electric machine (115) and a transmission compartment (335) of the The gearbox housing section (305) has at least one connecting channel (330) for the hydraulic connection of the winding head cooling (320) with the gearbox chamber (335), wherein an operating medium received in the gearbox chamber (335) and acting as a cooling and/or lubricating medium can be drawn off at least indirectly to the first suction point (310) via at least one bypass (350) in the machine housing section (300), characterized in that the hydraulic system (135) comprises at least one closing unit (601) by means of which the connecting channel (330) can be closed when a lateral acceleration is acting on the drive device (600) and thereby exceeds a certain maximum value.
  2. Drive unit (600) according to Claim 1 , characterized in that the winding head cooling (320) and the electric motor sump (380) are hydraulically connected by at least one drain channel (605), so that the operating medium can flow from the higher winding head cooling (320) into the lower electric motor sump (380).
  3. Drive unit (600) according to Claim 1 or 2 , characterized in that the locking unit (601) is designed such that it can be switched into a closed position due to the lateral acceleration force and is in the open switching position when no lateral acceleration force is acting on the drive device (100).
  4. Drive unit (600) according to Claim 1 or 2 , characterized in that the locking unit (601) can be switched at least into the open or closed switching position by means of an actuator.
  5. Drive unit (600) according to Claim 4 , characterized in that the drive device (600) comprises a sensor which detects at least the lateral acceleration force acting on the drive device (600) and allows the actuator to set the corresponding switching position of the locking unit (601) by means of a signal.
  6. Drive unit (600) according to Claim 4 or 5 , characterized in that the drive unit (600) comprises a further sensor which can detect the inclination of the vehicle and thus of the drive unit (600) transverse to the direction of travel, wherein, when a maximum value of the inclination is exceeded, the actuator is sent a signal to the actuator, which brings the locking unit into the closed switching position and closes the connecting channel.
  7. Drive device (600) according to one of the preceding claims, characterized in that the machine housing section (300) has two or more bypasses (350, 355) through which the cooling and/or lubricating medium received in the gearbox compartment (335) can be guided at least indirectly to the first intake point (310).
  8. Drive unit (600) according to Claim 7 , characterized in that an annular channel (360) is arranged in the machine housing section (300) in the direction of flow between the bypasses (350, 355) and the first suction point (310).
  9. Drive unit (600) according to Claim 7 or 8 , characterized in that two bypasses (350, 355) are arranged on opposite sides of a stator (315) of the electrical machine (115).
  10. Drive device (600) according to one of the preceding claims, characterized in that the respective bypass (350, 355) extends from a first axial end of the machine housing section (300) into the area of an opposite second axial end of the machine housing section (300).
  11. Drive device (600) according to one of the preceding claims, characterized in that the first suction point (310) is designed as a bore which extends substantially axially through the machine housing section (300).
  12. Drive device (600) according to one of the preceding claims, characterized by Figure 1 shows that the first intake point (310) is arranged vertically below a first axis of rotation (405) of the electric machine (115).
  13. Drive device (600) according to one of the preceding claims, characterized in that the gearbox housing section (305) has a second suction point (400) which is configured to be hydraulically connected to a second suction line (230) of the first pump (201) or to a further pump of the hydraulic system (135).
  14. Drive unit (600) according to Claim 13 , characterized in that the second intake point (400) is arranged vertically below a second axis of rotation (410) of the transmission (130).
  15. Electric drive axle comprising a drive unit (600) according to one of the preceding claims.
  16. Motor vehicle (105), comprising a drive unit (600) according to one of the Claims 1 until 14 or an electric drive axle Claim 15 .

Description

The present invention relates to a drive unit for a motor vehicle comprising a dry-sump hydraulic system for cooling and lubricating mechanical and/or electrical components, and an electric drive axle with the drive unit. The present invention also relates to a motor vehicle with such a drive unit or an electric drive axle. From the unpublished DE 10 2023 212 588.9 The applicant is aware of a drive device comprising an electric machine and a transmission unit, which are at least partially arranged in a common housing or interconnected sub-housings. A liquid operating medium is stored in the interconnected sub-housings or in a common housing for cooling and lubricating the mechanical and electrical components. The fact that the operating medium is stored in both sub-housings and can flow back and forth between them via the connection is hereinafter also referred to as a hydraulic connection between the sub-housings. In general, a hydraulic connection between several components is understood to mean that the operating medium can flow from one component to another through it. The liquid operating medium is usually a hydraulic fluid such as gear oil, hereinafter also referred to simply as oil. The operating fluid is transported to the points requiring cooling and lubrication by a lubricating/cooling oil pump, referred to below as a pressure pump. After dripping from the components requiring lubrication and cooling, which represent the consumers of the hydraulic system, the oil collects in a section of the housing. From this area, it is extracted by at least one pump and conveyed to a reservoir. This principle is also known as dry sump lubrication, and the extraction pump is referred to below as a dry sump or suction pump. The pressure pump then supplies the oil from the reservoir to the consumers. Such a hydraulic system with dry sump lubrication is used, for example, in... DE 10 2019 126 914 A1 known. Since the drive unit is used to propel a motor vehicle and is located within it, it, and consequently the operating fluid, is subject to vehicle dynamics, resulting in forces that occur during longitudinal and/or lateral acceleration. This is the case, for example, when braking, accelerating, or cornering. These inertial and centrifugal forces cause the operating fluid to shift within the housing, so that in certain situations the suction point of the dry sump pump becomes exposed, preventing the operating fluid from being drawn in and pumped into the reservoir. As an undesirable consequence, the reservoir is no longer filled, and the pressure pump can no longer deliver operating fluid to the consumers, potentially causing them to overheat, run dry, and wear out. During lateral acceleration of the vehicle, such as occurs when cornering, the operating fluid (usually oil) shifts within the drive unit in the 6 as illustrated and described later. This causes the oil to accumulate in the electric motor compartment, so that the electric motor is submerged in oil. The undesirable consequences of this are churning losses of the electric motor's rotor and thermal coupling between the stator and rotor. A similar displacement of the operating fluid causes the vehicle to tilt perpendicular to the direction of travel, as can occur, for example, with off-road vehicles. The object underlying the invention is therefore to create a drive unit with an improved hydraulic system, which enables good efficiency and non-critical thermal behavior. This is intended to reduce the effects of driving dynamic forces on the operating medium and its resulting displacement within the drive unit. The invention solves this problem by means of the subject matter of the independent claim. The dependent claims describe a preferred embodiment. Accordingly, a drive unit for a motor vehicle comprises a machine housing section with an electric motor and a transmission housing section with a transmission, as well as a hydraulic system for cooling and/or lubricating thermal and/or mechanical components in the machine housing section and the transmission housing section. In the machine housing section, an electric motor sump is formed below the electric motor, in which the operating fluid introduced for cooling can collect after dripping, and within which a first suction point is also formed, which is hydraulically connected to a first suction line of a first pump of the hydraulic system for cooling and/or lubricating thermal components. Here, two Between the winding head cooling system of the electric machine and a gearbox compartment of the gearbox housing section, at least one connecting channel is provided for the hydraulic connection of the winding head cooling system to the gearbox compartment. A connecting channel can be any configuration in the drive unit through which a hydraulic connection between the winding head cooling system and the gearbox compartment is possible, such as a bore, a pipe, a hose, a cast cavity, or an opening in a separating w