Drive unit with switchable gearbox and hydraulic module

Abstract

A drive unit (1) with a switchable transmission (3) and a hydraulic module (4), wherein a housing (5, 6) of the transmission (3) accommodates the hydraulic module (4), and the hydraulic module (4) has switchable valves (11), wherein the switchable valves (11) are arranged in a separate sub-chamber (22) of the housing (5, 6), wherein a separating element (23) for separating the sub-chamber (22) has an oil outlet opening (25), wherein means for conveying oil into the sub-chamber (22) are provided, wherein the separating element (23) has an oil inlet opening (24), wherein the switchable valves (11) are arranged one above the other, wherein the switchable valves (11) are arranged partly below and partly above an oil level (9) of an oil sump (8) formed within the housing (5, 6),and wherein the means for conveying oil through the oil inlet opening (24) into the subchamber (22) to the switchable valves (11) are provided and the oil outlet opening (25) is arranged at least at the level of the uppermost valve (11), characterized in that the means for conveying the oil comprise passive means, and that the passive means comprise oil collecting ribs in the housing (5, 6) of the transmission (3).

Description

[0001] The invention relates to a drive unit with a switchable transmission and a hydraulic module according to the preamble of patent claim 1.

[0002] In drive units that have a switchable transmission and a hydraulic module, it is known to design the hydraulic module such that it has a transmission control unit, a pump for pumping a hydraulic medium, in particular for pumping oil, and a plurality of valves. These valves serve in particular to control the oil flow in the transmission, in particular for the purpose of actuating the gears of the transmission by shifting one or more clutches and one or more brakes. The valves also control the supply of oil to defined points in the transmission, in particular for the purpose of lubricating or cooling transmission parts or transmission areas. To ensure lubrication, damping, or cooling of the valves, it is necessary for them to be arranged in the oil. In known drive units, the valves are therefore arranged in an oil sump.

[0003] A drive unit having the features of the preamble of patent claim 1 is known from DE 10 2013 113 748 A1. In this drive unit, the hydraulic medium—hydraulic oil—is supplied to a valve body by means of a pump. This valve body is arranged inside the subchamber, which functions as an auxiliary reservoir. The valve body is designed to control gear changes of a transmission of the drive unit. The hydraulic medium can be selectively directed to various components in the transmission to control the selective engagement and disengagement of clutches of the transmission. During operation of the transmission, the valve body releases a quantity of the hydraulic medium into the subchamber. In a region of the subchamber near the bottom, a lower oil outlet opening is provided in a separating element of the subchamber. The inflow of hydraulic medium into the main sump can be regulated by means of a valve.It is thus possible to compensate for a low fill level of hydraulic medium in the main sump by draining a quantity of the hydraulic medium contained in the auxiliary tank into the main sump when the valve is open. Above the valve, a further oil outlet opening is provided in the separating element, ensuring overflow of the hydraulic medium when the valve associated with the lower oil outlet opening is closed. This overflow is particularly intended to direct overflowing hydraulic medium over a motor-generator arranged within the housing area containing the main sump in order to cool it. Generally, this overflow is designed to transfer hydraulic medium from the subchamber to the main sump when the fill level of the hydraulic medium in the subchamber reaches a predetermined level.

[0004] DE 10 2007 033 475 A1 also discloses a drive unit with a switchable transmission and a hydraulic module. This hydraulic module is arranged in a subchamber of the housing separated from a main chamber with a main sump. The hydraulic module has a valve body arrangement comprising a plurality of valves whose function is to control the engagement of the transmission's torque transmission and also to selectively provide pressurized fluid to other components within the transmission. When the transmission is in operation, hydraulic fluid flows from the valve body arrangement into the subchamber and can generally reach the main sump via a lower outlet opening assigned to this subchamber. This outflow through the lower outlet opening can be regulated by means of a thermal valve arrangement arranged there.In an upper area of ​​the subchamber, above the valve body assembly, an upper outlet opening for the hydraulic medium is provided. Both outlet openings, the lower outlet opening and the upper outlet opening, allow the hydraulic medium to flow or reach, as required, from the valve body side of the housing assigned to the valve body to a gear wheel side of the housing.

[0005] The object of the present invention is to further develop a drive unit with a switchable transmission and a hydraulic module in such a way that, despite a relatively low level of an oil sump, a permanently safe operation of the valves is ensured.

[0006] The problem is solved by a drive unit which is designed according to the features of patent claim 1.

[0007] In the drive unit with the switchable transmission and the hydraulic module, a transmission housing accommodates the hydraulic module. The hydraulic module is thus arranged within the housing. The hydraulic module has the switchable valves arranged one above the other. The switchable valves are arranged partly below and partly above an oil level in an oil sump formed within the housing. Furthermore, the valves are arranged in a separate subchamber of the housing. A separating element for separating the subchamber has an oil inlet opening and an oil outlet opening. Means are provided for conveying oil through the oil inlet opening into the subchamber, and the oil outlet opening is arranged at least at the level of the uppermost valve.

[0008] Thus, thanks to the means for conveying the oil within the subchamber, an oil level can be achieved that is higher than the oil level in the oil sump and, due to the position of the oil outlet opening, is at least at the level of the topmost valve. This ensures that all valves arranged one above the other are adequately supplied with oil.

[0009] In principle, it is sufficient if the oil outlet opening extends only as far as the topmost valve, so that the oil outlet opening is positioned exactly at the height of the topmost valve. This is sufficient to supply this valve with oil. However, it is considered particularly advantageous if the oil outlet opening is positioned higher than the topmost valve. This way, the topmost valve is completely immersed in the oil contained in the subchamber. Consequently, all valves are completely immersed in the oil contained in the subchamber.

[0010] The separating element can be designed in various ways, provided it serves the purpose of forming a separating space within the housing. It is considered particularly advantageous if the separating element is designed as a container or enclosure.

[0011] According to the invention, the means for conveying the oil comprise at least passive means, wherein the passive means comprise oil collecting ribs in the housing of the transmission. The means for conveying the oil can additionally comprise active means, in particular a pump.

[0012] According to a preferred embodiment, the container is open at the top, or the partition wall defines the compartment of the housing in an open manner at the top. This results in a particularly simple design of the separated compartment of the housing.

[0013] According to a preferred development, it is provided that the container or the partition wall forms an overflow for the purpose of oil return into the oil sump.

[0014] The reservoir or partition can cooperate with an oil return line to components of the drive unit. This oil return line is directed in particular toward the hydraulic module or an actuator and / or the transmission and / or a drive motor forming part of the drive unit and interacting with the transmission, and / or a control unit or control units. The oil volume flow is thereby used for further cooling and lubrication of components such as the transmission control unit, bearings, gear set, electric motor, which is in particular an electric machine, etc.

[0015] The hydraulic module is preferably designed to include the valves, a pump for pumping the oil, and an electric transmission control unit. Furthermore, the hydraulic module may include components relating to hydraulic routing, in particular hydraulic plates, and / or a pressure accumulator and / or a pressure filter and / or an intake filter. The hydraulic routing components or hydraulic plates function to channel the hydraulic medium or oil through channels or the like.

[0016] According to a preferred development of the invention, the drive unit comprises a drive motor, in particular an electric motor. The transmission preferably comprises a first housing part facing the drive motor and a second housing part, wherein the second housing part is connected to the first housing part on the side facing away from the drive motor, and the hydraulic module is mounted exclusively in the second housing part. This makes it possible to supply the second housing part and the hydraulic module as a preassembled unit for subsequent further assembly of the drive unit.

[0017] According to a preferred embodiment of the second housing part, it is provided that it is cup-shaped. The hydraulic module is arranged inside the cup.

[0018] The transmission is designed, in particular, as a two-speed transmission. This transmission preferably comprises a spur gear set and a planetary gear set.

[0019] The transmission is designed in particular in such a way that in a first gear of a transmission a clutch is opened and a brake is closed, and in a second gear the clutch is closed and the brake is opened.

[0020] Further features of the invention will become apparent from the dependent claims, the accompanying drawings, and the description of two preferred embodiments shown in the drawings, without being limited thereto. It shows: Fig. 1 a drive unit with an electric motor and a switchable transmission, illustrated in a side view, Fig. 2 a vertical section through the Fig. 1 shown drive unit, illustrated in a schematic representation, Fig. 3 a first embodiment of the drive unit, illustrated in a section AA in Fig. 2, Fig. 4 a second embodiment of the drive unit, illustrated in a section AA in Fig. 2.

[0021] The Fig. 1, Fig. 3 and Fig. 4 show a drive unit 1 with an electric motor 2 and a switchable transmission 3. The electric motor 2 is a permanently excited synchronous machine (PSM), and the switchable transmission 3 is a two-speed transmission. The transmission 3 has a spur gear set and a planetary gear set. In a first gear, a clutch of the transmission 3 is disengaged and a brake of the transmission 3 is engaged; however, in second gear, the clutch is engaged and the brake is disengaged. The drive unit's output is assigned to a housing area next to the electric motor 2, and a pulse-width inverter (PWR) is arranged in this area.

[0022] The drive unit 1 has inside the switchable transmission 3 a Fig. 2 schematically illustrated hydraulic module 4 for actuating the gears of the transmission 3 and lubricating gear sets of the transmission 3.

[0023] As can be seen from the figures, the transmission 3 has a first transmission housing 5 facing the electric motor 2 and a second transmission housing 6. The transmission housing 6 is connected to the transmission housing 5 on the side facing away from the electric motor 2. The hydraulic module 4 is mounted in the transmission housing 6. Hydraulic pressure lines for actuating and lubricating the transmission 3 are integrated into the transmission housing 6.

[0024] The transmission housing 6 has a housing region 7 that is cup-shaped. The cup volume is formed as a partial volume of the transmission housing 6. The housing region 7 extends essentially vertically and forms an oil sump 8. The oil level of the oil sump 8 is designated by reference numeral 9. Additionally, the arrow 10 illustrates the forward direction of travel of a motor vehicle, in particular a passenger car, equipped with the drive unit 1.

[0025] The hydraulic module 4, whose system boundary is illustrated by the dashed line 27, has various valves 11, specifically six valves 11, a pump 12 for pumping the hydraulic fluid, in this case oil, a pressure accumulator 13, an intake filter 14, hydraulic plates 15, and an electric transmission control unit 16. Direct contact is established between the pump 12 and the transmission control unit 16. Reference numeral 17 illustrates the contact between the valves 11 and the transmission control unit 16.

[0026] Due to the described structure, the transmission housing 6 represents an integral housing for accommodating the entire hydraulic actuator system, including the transmission control unit 16, and thus for accommodating the hydraulic module 4.

[0027] Reference numeral 18 designates a housing that is connected to the transmission housing 5 on the side facing away from the transmission housing 6. This housing 18 forms a housing component of the electric machine and the output of the drive unit 1.

[0028] The representations of the Fig. 3 and Fig. 4 shows further details of the drive unit 1 for both embodiments.

[0029] Shown are vent valves 19, preferably two to three vent valves, arranged in the area of ​​the transmission housing 6, pressure sensors 20, preferably two to three pressure sensors, pressure filters 28, preferably one to two pressure filters, the pump 12 with direct screw connection to the transmission control unit 16, the hydraulic plates 15 or valve box with routing, and finally oil transfer points 21 for transmission actuators (high pressure).

[0030] Regarding both embodiments shown according to the Fig. 3 and Fig. 4, a vertical arrangement of the valves 11 is provided for the benefit of an optimal, project-specific package. Here, the six valves 11 are arranged exactly one above the other, thus not offset laterally by a certain amount. Due to the special design of the drive unit 1 in the area of ​​the hydraulic module 4, it is ensured that all valves 11 are arranged in the oil. This ensures, in particular, the lubrication, damping, and cooling of the valves 11. This arrangement of all valves 11 in the oil is guaranteed even though the oil level is limited by the level 9 of the oil sump, so that only the lower valves 11 are arranged below this level 9.

[0031] This arrangement of all valves 11 in the oil is achieved by the fact that according to the two embodiments according to the Fig. 3 and Fig. 4, the valves 11 are arranged in a separate subchamber 22 of the housing of the transmission 3, specifically the transmission housing 6. A separating element 23 is provided for separating the subchamber 22. The separating element 23 has an oil inlet opening 24 and an oil outlet opening 25. Furthermore, means are provided for conveying oil through the oil inlet opening 24 into the subchamber 22. The oil outlet opening 25 is arranged at least at the level of the uppermost valve 11. Thus, oil only emerges from the oil outlet opening 25 when oil has reached the level of the uppermost valve 11. The means for conveying the oil through the oil inlet opening 24 into the subchamber 22 may well be the pump 12, which thus serves not only the purpose of supplying oil for actuating gears of the transmission and lubricating gear sets of the transmission, but also of supplying it to the subchamber 22.

[0032] In the embodiment according to the Fig. 3, the separating element 23 is designed as a container. This container is provided with an oil inlet opening 24 at the bottom, on the side facing the pump 12, so that oil flows into the container opposite to the forward direction 10. The flow of oil through the container is illustrated by arrows 26. The container or the enclosure of the valves 11, and possibly also parts that actuate the valves, is designed as an upwardly open container or overflow vessel, with an oil return line into the oil sump of the transmission 3 or the drive unit 1.

[0033] In the embodiment according to the Fig.4, the reservoir or enclosure of the valves 11 or valve actuation is designed as a container with an oil return in the direction of the hydraulic module or actuators and / or transmission and / or drive unit and / or control unit or control units, etc. As a result, the volume flow can be used for further cooling and lubrication of components, such as the transmission control unit, bearings, gear set, electric machine, etc. Apart from the described oil supply to the reservoir or enclosure, which takes place actively, for example, by means of the pump 12, according to the invention at least a passive oil supply takes place, namely by means of oil collecting ribs in the transmission. The cooling oil volume flow can be used to cool other components, such as the transmission control unit.

[0034] Both embodiments thus illustrate an extended or additional oil sump by means of the separating element 23, which represents the function of a container or enclosure of the valves 11, so that their lubrication, damping, cooling, etc. is ensured. List of reference symbols 1 drive unit 2 electric machine 3 gearboxes 4 Hydraulic module 5 Gearbox housing 6 Gearbox housing 7 Housing area 8 Oil sump 9 Level 10 Forward direction 11 Valve 12 Pump 13 pressure accumulators 14 intake filters 15 Hydraulic plate 16 Transmission control unit 17 Contacting 18 housings 19 vent valve 20 pressure sensor 21 Oil transfer point 22 subspace 23 Separator 24 Oil inlet opening 25 Oil outlet opening 26 Arrow 27 System boundary hydraulic module 28 pressure filters

Claims

[1] Drive unit (1) with a switchable transmission (3) and a hydraulic module (4), wherein a housing (5, 6) of the transmission (3) accommodates the hydraulic module (4) and the hydraulic module (4) has switchable valves (11), wherein the switchable valves (11) are arranged in a separate sub-chamber (22) of the housing (5, 6), wherein a separating element (23) for separating the sub-chamber (22) has an oil outlet opening (25), wherein means for conveying oil into the sub-chamber (22) are provided, wherein the separating element (23) has an oil inlet opening (24), wherein the switchable valves (11) are arranged one above the other, wherein the switchable valves (11) are arranged partly below and partly above an oil level (9) of an oil sump (8) formed within the housing (5, 6),and wherein the means for conveying oil through the oil inlet opening (24) into the sub-chamber (22) to the switchable valves (11) are provided and the oil outlet opening (25) is arranged at least at the level of the uppermost valve (11), , characterized by that the means for conveying the oil comprise passive means, and that the passive means comprise oil collecting ribs in the housing (5, 6) of the gearbox (3). [2] Drive unit according to claim 1, characterized by that the oil outlet opening (25) is arranged higher than the uppermost valve (11). [3] Drive unit according to claim 1 or 2, characterized by that the separating element (23) is designed as a container or as a frame. [4] Drive unit according to one of claims 1 to 3, characterized by that the means for extracting the oil further comprise active agents. [5] Drive unit according to claim 4, characterized by that the active means comprise a pump (12). [6] Drive unit according to claim 3, characterized by that the container is open at the top. [7] Drive unit according to one of claims 1 to 6, characterized by that the separating element (23) limits the partial space (22) of the housing (5, 6) open at the top. [8] Drive unit according to one of claims 1 to 7, characterized by that the separating element (23) forms an overflow for the purpose of oil return into the oil sump (8). [9] Drive unit according to one of claims 1 to 8, characterized by that the separating element (23) cooperates with an oil return to components of the drive unit (1). [10] Drive unit according to one of claims 1 to 9, characterized by that the hydraulic module (4) has the valves (11), a pump (12) and an electric transmission control unit (16). [11] Drive unit according to claim 10, characterized bythat the hydraulic module (4) has components relating to hydraulic routing and / or a pressure filter (28) and / or a pressure accumulator (13) and / or an intake filter (14). [12] Drive unit according to claim 11, characterized by that the components relating to hydraulic routing are hydraulic plates (15). [13] Drive unit according to one of claims 1 to 12, characterized by that the drive unit (1) has a drive machine (2). [14] Drive unit according to claim 13, characterized by that the drive machine (2) is an electric machine. [15] Drive unit according to claim 14, characterized by that the transmission (3) has a first housing part (5) facing the drive machine (2) and a second housing part (6), wherein the second housing part (6) is connected to the first housing part (5) on the side facing away from the drive machine (2), and the hydraulic module (4) is mounted exclusively in the second housing part (6). [16] Drive unit according to claim 15, characterized by that the second housing part (6) has a pot-shaped section, wherein the hydraulic module (4) is arranged in the interior of the pot. [17] Drive unit according to one of claims 1 to 16, characterized by that the transmission (3) is designed as a two-speed transmission. [18] Drive unit according to claim 17, characterized by that the transmission (3) comprises a spur gear set and a planetary gear set.

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