Procedures for operating a supply system and supply system

Abstract

The invention relates to a method for operating a supply system (10) in which components (11, 12, 13, 14) of a drive system (9) are supplied with lubricant and / or coolant, wherein an electrically driven feed pump (15) is operated during normal operation of the drive system (9) and thereby lubricant and / or coolant is conveyed to the components (11, 12, 13, 14) in the supply system (10) via the electrically driven feed pump (15).During special operation in which the electrically driven feed pump (15) is switched off while the drive system (9) is operating, at least a portion (11, 14) of the components (11, 12, 13, 14) in the supply system (10; 20) are supplied with lubricant and / or coolant only via a mechanically driven feed pump (16), the mechanically driven feed pump (16) being driven for its operation via an output (18) of a motor vehicle drive train (2) comprising the drive system (9). During operation, the mechanically driven feed pump (16) delivers only a minimum quantity, which corresponds to the minimum requirement necessary to supply at least the portion (11, 14) of the components (11, 12, 13, 14).

Description

[0001] The invention relates to a method for operating a supply system in which components of a drive system are supplied with lubricant and / or coolant, wherein an electrically driven feed pump is operated during normal operation of the drive system and thereby supplies lubricant and / or coolant to the components in the supply system via the electrically driven feed pump, and wherein during special operation in which the electrically driven feed pump is switched off during operation of the drive system, at least some of the components in the supply system are supplied with lubricant and / or coolant only via a mechanically driven feed pump. Furthermore, the invention relates to a supply system in which components of a drive system can be supplied with lubricant and / or coolant.

[0002] In drive trains, supply systems typically provide individual components with lubricant and / or coolant to lubricate and / or cool each component and / or to operate it. Most supply systems are hydraulic systems, using hydraulic fluid, usually oil. During operation, a sufficient supply to each component must be ensured whenever possible. Increasingly, supply systems incorporate electrically driven pumps. However, some systems also include a mechanically driven pump to ensure continued supply to at least some components in the system in case of failure or similar issues.

[0003] EP 2 855 928 B1 discloses a supply system for a drive system in the form of a wind turbine gearbox. This supply system provides lubricant to components such as bearings and gears, and includes both an electrically driven and a mechanically driven pump. According to a specific method, the supply system described in EP 2 855 928 B1 can be operated such that, during normal gearbox operation, the electrically driven pump is supplied with electrical energy, thereby delivering lubricant to the bearings and gears via both pumps.Furthermore, during special operation in which the electrically driven feed pump is not operated during active operation of the gearbox due to a lack of electrical power supply, only a part of the components, namely the gearbox bearings, are supplied with lubricant by the mechanically driven feed pump alone.

[0004] Document DE 10 2013 019 319 A1 discloses a cooling arrangement for a motor vehicle powertrain, comprising a first cooling pump having a first cooling pressure port through which fluid can be supplied for cooling at least one component of the powertrain, an electric motor driving the first cooling pump, and a second cooling pump having a second cooling pressure port through which fluid can be supplied for cooling at least one component of the powertrain, wherein the second cooling pump can be driven via an auxiliary drive of a drive motor. The second cooling pump is designed as a variable displacement pump.

[0005] Based on the prior art described above, the object of the present invention is, on the one hand, to keep losses as low as possible in a supply system of a drive system and, on the other hand, to avoid impairment of components of the drive system that would otherwise occur due to insufficient supply.

[0006] This problem is solved from a process engineering perspective, starting from the preamble of dependent claim 1 in conjunction with its characterizing features. Furthermore, a solution is provided from an apparatus engineering perspective, starting from the preamble of dependent claim 5 in conjunction with its characterizing features. The subsequent dependent claims each represent advantageous embodiments of the invention.

[0007] According to the dependent claim 1, a method for operating a supply system supplies components of a drive system with lubricant and / or coolant. During normal operation of the drive system, an electrically driven pump is operated, thereby supplying lubricant and / or coolant to the components in the supply system. During special operation, in which the electrically driven pump is switched off during operation of the drive system, at least some of the components in the supply system are supplied with lubricant and / or coolant only via a mechanically driven pump.

[0008] During normal operation of the drive system, the supply system operates in such a way that the components are supplied via an electrically driven pump. This pump is powered by electricity and delivers lubricant and / or coolant to the components. In contrast, special operation occurs when the electrically driven pump is not operating during normal drive system operation, meaning it does not deliver lubricant and / or coolant. Instead, during special operation, only a mechanically driven pump is used, delivering lubricant and / or coolant to supply at least some of the components.

[0009] According to the invention, the special operating mode always occurs when the electrically driven pump is not operating during the normal operation of the drive system. This special operating mode can be a deliberately induced operating state in which the electrical power supply to the electrically driven pump is intentionally interrupted, or an operating state caused by a fault, such as a failure of the electrically driven pump or its power supply.

[0010] According to dependent claim 1, the invention further comprises the technical teaching that the mechanically driven pump is driven via an output of a motor vehicle powertrain comprising the drive system. During operation, the mechanically driven pump delivers only a minimum quantity of lubricant and / or coolant, corresponding to the minimum requirement necessary to supply at least some of the components. In other words, the mechanically driven pump is driven via an output of a motor vehicle powertrain comprising the drive system. During operation, the mechanically driven pump provides only a minimum quantity of lubricant and / or coolant, corresponding to the minimum requirement necessary to supply at least some of the components.

[0011] The operation of a supply system according to the invention has the advantage that, firstly, a supply of at least some of the components is ensured by means of the mechanically driven pump even when no supply via the electrically driven pump takes place or cannot take place during operation of the drive system. This prevents impairment or even damage to at least some of the components in the supply system due to an otherwise lacking supply. Furthermore, because the mechanically driven pump only delivers the minimum quantity during operation, losses are minimized that would otherwise result from an excessively high level of lubricant and / or coolant in the supply system, and in particular from splashing of rotating, immersed components.Overall, this means that on the one hand an efficient operation of the supply system can be achieved, and on the other hand a minimum supply can be permanently guaranteed for at least some of the components.

[0012] The drive system whose components need to be supplied is therefore at least part of a motor vehicle's drivetrain, whereby the drive system can specifically be a motor vehicle transmission, a motor vehicle drive axle, and in particular an electrically driven motor vehicle drive axle, etc. The mechanically driven pump is driven for its operation by an output of the motor vehicle's drivetrain, for which purpose the mechanically driven pump is coupled to an output of the drive system during its operation. This output is preferably a component permanently coupled to at least one drive wheel of the motor vehicle's drivetrain, for example, a transmission output shaft.

[0013] If the mechanically driven pump is driven via the output shaft, it only supplies the minimum quantity of lubricant and / or coolant. This minimum quantity is chosen to meet the minimum requirement necessary to supply at least some of the components without impairing or damaging them. Therefore, the mechanically driven pump is designed solely to supply this minimum quantity.

[0014] The mechanically driven feed pump could be operated in addition to the electrically driven feed pump during normal operation. This would result in both pumps supplying the components simultaneously during normal operation. For this purpose, the mechanically driven feed pump would be permanently coupled to the output shaft.

[0015] According to the invention, the mechanically driven feed pump is decoupled from the output during normal operation and thereby switched off. This reduces losses in the supply system during normal operation by eliminating the need to drive the mechanically driven feed pump. In a further embodiment, the decoupling of the mechanically driven feed pump is carried out depending on a pressure in the supply system and / or via an actuator. For example, a pressure-controlled coupling or a coupling controlled by the actuator could be provided, with the actuator also acting on the coupling depending on the pressure. The pressure in the supply system is, in particular, the pressure prevailing on a pressure side of the electrically driven feed pump.

[0016] In a further embodiment of the invention, during special operation, only those components are supplied that absolutely require a constant supply during normal operation of the drive system. Consequently, the supply during special operation is limited to the components that absolutely require a supply. This allows the minimum quantity to be supplied to be kept small while still preventing any impairment of the drive system components.

[0017] In a further development of the invention, the electrically driven pump performs demand-based pumping during normal operation. This improves efficiency even during normal operation, as the electrically driven pump only supplies the actual amount of lubricant and / or coolant required.

[0018] According to dependent claim 5, components of a drive system can be supplied with lubricant and / or coolant in a supply system. Furthermore, an electrically driven feed pump and a mechanically driven feed pump are provided, wherein the electrically driven feed pump supplies lubricant and / or coolant to the components in the supply system during normal operation of the drive system. Additionally, during special operation in which the electrically driven feed pump is switched off during operation of the drive system, the mechanically driven feed pump alone supplies at least some of the components with lubricant and / or coolant.

[0019] In the supply system, components of the drive system are supplied with lubricant and / or coolant. The components to be supplied can be components requiring lubrication and / or cooling, or both. In principle, the respective component can be a bearing, for example a plain bearing or a rolling bearing, a gear stage where a tooth mesh requires lubrication, a rotor or stator of an electric machine, etc. The lubricant and / or coolant supplied is, in particular, a liquid, and preferably oil.

[0020] For the purposes of the invention, an "electrically driven pump" is understood to be a pump that requires electrical energy for operation. In contrast, a "mechanically driven pump" is a pump that requires mechanical energy for operation.

[0021] According to dependent claim 5, the invention comprises the technical teaching that the mechanically driven pump is driven via an output of a motor vehicle drivetrain comprising the drive system. Furthermore, the mechanically driven pump delivers only a minimum quantity when driven, corresponding to the minimum requirement necessary to supply at least some of the components. In other words, the mechanically driven pump is driven via an output of a motor vehicle drivetrain comprising the drive system. Moreover, the mechanically driven pump is designed such that, when driven, it delivers only a minimum quantity corresponding to the minimum requirement of lubricant and / or coolant for supplying at least some of the components.

[0022] Advantageously, the supply system designed according to the invention allows for a minimum supply to at least some of the components by providing a corresponding supply via the mechanically driven pump when the electrically driven pump is not operating and the drive system is in active operation. This prevents impairment or damage to at least some of the components in the supply system due to an otherwise insufficient supply when the electrically driven pump is not operating. Furthermore, since the mechanically driven pump only covers the minimum requirement during operation, losses are minimized that would otherwise result from excessive levels of lubricant and / or coolant, and in particular from splashing of rotating, immersed components.Overall, a supply system can be created that is efficient to operate and in which at least some of the components always have a minimum necessary supply.

[0023] In a further development of the invention, a coupling is arranged between the mechanically driven feed pump and the output shaft, allowing the mechanically driven feed pump to be disconnected from the output shaft. In this case, the mechanically driven feed pump is not permanently coupled to the output shaft; instead, the coupling is achieved via the intermediate coupling. This allows the mechanically driven feed pump to be selectively disconnected during normal operation, thereby preventing its operation and reducing losses and increasing efficiency. Preferably, the coupling is controlled based on the pressure prevailing in the supply system and / or actuated by an actuator.

[0024] Alternatively, the mechanically driven feed pump can also be permanently coupled to the output of the drive system.

[0025] Advantageous embodiments, which are explained below, are illustrated in the drawings. They show: Fig. 1 a schematic representation of a motor vehicle comprising a supply system according to a first embodiment of the invention; and Fig. 2 a schematic representation of a motor vehicle with a supply system according to a second embodiment of the invention.

[0026] Out of Fig. Figure 1 shows a schematic representation of a motor vehicle 1, which can be a passenger car or a commercial vehicle. The motor vehicle 1 comprises a motor vehicle drivetrain 2, in which a drive motor 3 can be coupled, or is coupled, on the output side via a transmission 4 and a differential 5 to drive wheels 6 and 7 of a motor vehicle drive axle 8. The drive motor 3 can be an internal combustion engine or an electric motor.

[0027] The transmission 4 and the differential 5, which form a drive system 9 as part of the motor vehicle drivetrain 2, are associated with a supply system 10 in which components 11, 12, 13 and 14 of the drive system 9 can be supplied with lubricant in the form of oil. In the present case, the supply system 10 is configured according to a first embodiment of the invention. Component 11 is a bearing of the transmission 4, component 12 is a gear set of the transmission 4, component 13 is a bearing of the differential 5, and component 14 is a gear set of the differential 5.

[0028] The supply system 10 has an electrically driven pump 15 and a mechanically driven pump 16. An electric motor 17 is associated with the electrically driven pump 15, which drives the pump 15 when electrical energy is supplied. During operation, the electrically driven pump 15 draws oil from a reservoir of the supply system 10 (not shown here) and then pumps the oil to components 11 to 14. The pumping rate is adjusted according to demand by controlling the electric motor 17 and thus also the electrically driven pump 15.

[0029] The mechanically driven pump 16 is integrated into the drive system between the transmission 4 and the differential 5 and is thus permanently coupled to an output 18 of the vehicle drivetrain 2. This output 18 is in the form of the coupling permanently established via the differential 5 to the drive wheels 6 and 7. The mechanically driven pump 16 is driven by the drive torque acting between the transmission 4 and the differential 5. When driven, the pump 16 draws oil from the reservoir of the supply system 10 and supplies it to components 11 to 14. The pump 16 is designed to deliver a minimum quantity of oil, meaning it covers the minimum amount required to supply components 11 and 14.

[0030] In normal operation of the vehicle powertrain 2, and thus also of the drive system 9 (i.e., during normal driving of the vehicle 1), the electrically driven pump 15 of the supply system 10 is driven by the electric motor 17. Simultaneously, the mechanically driven pump 16 is driven due to its integration between the transmission 4 and the differential 5. As a result, the two pumps 15 and 16 together supply oil to components 11 and 14, while components 12 and 13 are supplied solely by the electrically driven pump 15. The electrically driven pump 15 provides demand-based supply, taking into account the minimum oil requirement already supplied by the mechanically driven pump 16 for components 11 and 14.

[0031] Instead of normal operation, a special operating mode of the vehicle powertrain 2, and thus also of the drive system 9, can also occur. This is the case when the vehicle 1 is moving, but the ignition is switched off or power in the vehicle powertrain 2 is deliberately reduced. The former can occur, for example, when the vehicle 1 is being towed or hauled, while the power reduction can occur particularly in the event of a fault.

[0032] During special operation, the electrically driven feed pump 15 is not driven, while the mechanically driven feed pump 16, due to its permanent coupling with the output 18, is driven and thus also delivers oil to components 11 and 14. This ensures at least the necessary supply to components 11 and 14 when the vehicle 1 is in motion, and thus also prevents their impairment or damage.

[0033] Fig. Figure 2 shows a schematic view of a motor vehicle 19, which largely corresponds to the variant according to Fig. 1 corresponds to. The only difference compared to the variant after Fig. 1 is that the mechanically driven feed pump 16 in a supply system 20 is now not permanently integrated between the gearbox 4 and the differential gearbox 5, but is only integrated by closing an intermediate clutch 21.

[0034] The clutch 21 is only engaged during the special operation of the vehicle drivetrain 2 of the vehicle 19, so that the mechanically driven pump 16 only supplies oil to components 11 and 14 under these conditions. When the vehicle drivetrain 2 is in its normal operation, the clutch 21 disengages the mechanically driven pump 16 from the output 18, thus preventing any oil supply via the pump 16. In this case, components 11 to 14 are supplied solely by the electrically driven pump 15.

[0035] The coupling 21 can be controlled via an actuator (not shown here) or depending on the pressure provided in the supply system 20 by the electrically driven pump 15. Otherwise, the motor vehicle 19 and, in particular, the supply system 20 correspond to the variant according to [reference]. Fig.1, so that reference is made to what is described here.

[0036] By means of the variants of a drive system according to the invention, losses can be kept as low as possible on the one hand, and on the other hand, impairment of components of the drive system that would otherwise occur due to insufficient supply can be avoided. Reference sign 1 motor vehicle 2 Motor vehicle powertrain 3 Drive machine 4 gearboxes 5 Differential gears 6 drive wheel 7 drive wheel 8 Motor vehicle drive axle 9 Drive system 10 Supply system 11 components 12 components 13 components 14 components 15 electrically driven pumps 16 mechanically driven feed pumps 17 Electric machine 18 Drive 19 motor vehicle 20 Supply system 21 Clutch

Claims

Method for operating a supply system (10; 20) in which components (11, 12, 13, 14) of a drive system (9) are supplied with lubricant and / or coolant, wherein an electrically driven feed pump (15) is operated during normal operation of the drive system (9) and thereby supplies lubricant and / or coolant to the components (11, 12, 13, 14) in the supply system (10; 20) via the electrically driven feed pump (15), and wherein during special operation in which the electrically driven feed pump (15) is switched off during operation of the drive system (9), in the supply system (10;20) at least a part (11, 14) of the components (11, 12, 13, 14) is supplied with lubricant and / or coolant only via a mechanically driven feed pump (16), characterized in that the mechanically driven feed pump (16) is driven for its operation via an output (18) of a motor vehicle drive train (2) comprising the drive system (9), and that only a minimum quantity is delivered via the mechanically driven feed pump (16) during its operation, which corresponds to a minimum requirement necessary to supply at least the part (11, 14) of the components (11, 12, 13, 14), wherein the mechanically driven feed pump (16) is decoupled from the output (18) and thereby switched off during normal operation.; Method according to claim 1, characterized in that the decoupling of the mechanically driven feed pump (16) is carried out depending on a pressure in the supply system (10; 20) and / or via an actuator. Method according to one of the preceding claims, characterized in that during special operation only the part (11, 14) of the components (11, 12, 13, 14) is supplied which must be permanently supplied during operation of the drive system (9). Method according to one of the preceding claims, characterized in that the electrically driven pump (15) performs demand-based pumping during normal operation. Supply system (10; 20) in which components (11, 12, 13, 14) of a drive system (9) can be supplied with lubricant and / or coolant, wherein an electrically driven feed pump (15) and a mechanically driven feed pump (16) are provided, wherein the electrically driven feed pump (15) supplies lubricant and / or coolant to the components (11, 12, 13, 14) in the supply system (10; 20) during normal operation of the drive system (9), and wherein the mechanically driven feed pump (16) alone supplies at least a part (11, 14) of the components (11, 12, 13, 14) with lubricant and / or coolant during special operation in which the electrically driven feed pump (15) is switched off during operation of the drive system (9), characterized in that a drive of the mechanically driven feed pump (16) is provided via an output (18) of a drive system (9) comprehensive motor vehicle powertrain (2) is carried out,and that the mechanically driven feed pump (15) only delivers a minimum quantity when driven, which corresponds to a minimum requirement necessary to supply at least part (11, 14) of the components (11, 12, 13, 14), wherein a coupling (21) is arranged between the mechanically driven feed pump (16) and the output (18), via which the mechanically driven feed pump (16) can be disconnected from the output (18). Supply system (20) according to claim 5, characterized in that the coupling (21) is controlled depending on a pressure prevailing in the supply system (20) and / or can be actuated via an actuator.

Images