EP2578837B1 - Coolant transport device and method for operating same - Google Patents

Description

The invention relates to a coolant conveying device with a coolant pump, which can be driven by a first and a second drive unit via a planetary gear, wherein the planetary gear has a first input shaft for the first drive unit and a second input shaft for the second drive unit. The invention further relates to a method for operating a coolant delivery device.

Coolant conveyors of the type mentioned are known from the prior art. For example, this describes DE 10 2006 041 687 A1 a coolant pump for a cooling circuit of an internal combustion engine. The coolant pump has an impeller and a pump shaft rotatably connected to the impeller, which is connectable via a belt drive with the crankshaft with the internal combustion engine. This can be set between the speed of the crankshaft and the speed of the pump shaft different ratios, a planetary gear is disposed between the pump shaft and the belt drive, which is preferably coupled to an electric drive motor. Extensive variations of the delivery rate of the coolant pump are already possible with such a coolant pump. However, due to the planetary gear, it has an unfavorable performance, especially in terms of power consumption, acoustics, heat generation and wear on. Similar coolant delivery devices are also apparent from the documents DE 102 14 637 A1 . DE 60 2005 000 638 T2 and DE 10 2006 048 050 A1 ,

It is therefore an object of the invention to provide a coolant delivery device, which does not have the disadvantages mentioned above, but in particular on the one hand allows a variation of the delivery rate of the coolant pump in a wide range and on the other has a favorable operating behavior in the context of the above aspects.

This is achieved according to the invention with a coolant conveying device with the features of claim 1. In this case, a coupling is provided, via which the input shafts are coupled directly to one another in at least one operating state. The Coolant pump is driven by the planetary gear of the first and the second drive unit. This means that they can be driven together only by the first, only by the second or by both drive units. The first drive unit is coupled via the first input shaft with the planetary gear, while this is the case for the second drive unit via the second input shaft. Thus, in each case a corresponding operative connection of the first or second drive unit to the planetary gear and via this to the coolant pump is produced via the two input shafts. Due to the numerous moving parts in the planetary gear, in particular by the rolling of the gears, the known from the prior art coolant pump has an unfavorable operating behavior. In particular, the friction losses are very high, which adversely affects energy consumption, acoustics, heat generation and wear.

For this reason, the coupling is provided according to the invention. By means of these, the input shafts for the first and the second drive unit can be directly coupled to one another in at least one operating state. When the input shafts are directly coupled together, they have the same speed. Under the coupling directly with each other is therefore not to be understood as an indirect coupling via the planetary gear or gears of the planetary gear. Rather, there should be a direct and immediate connection between the input shafts, so that both have the same speed. By means of the clutch, therefore, a rotationally fixed coupling of the input shafts can be realized. In the at least one operating state, at least part of the desired power range of the coolant conveying device or of the coolant pump can be covered. If an operation outside this range is desired, then the input shafts may be decoupled from each other in the further operating states so that they no longer communicate directly with one another. Accordingly, the unfavorable operating behavior is still present in this further operating range. However, because at least temporarily the coupling of the input shafts is provided by means of the coupling, the time proportion of these further operating ranges can be significantly reduced in a total operating time of the coolant delivery device. Overall, thus the performance is improved.

A further development of the invention provides that the planetary gear has a sun gear, a ring gear and a planet carrier with at least one planetary gear producing an operative connection between the sun gear and the ring gear, wherein the sun gear to the first input shaft, the planet carrier to the second input shaft and the coolant pump are connected to an output shaft connected to the ring gear. The planetary gear accordingly has a substantially known structure. The two drive units are connected to the sun gear and the planet carrier, so connected directly to this. The speed of the sun gear corresponds to the extent of the rotational speed of the first input shaft and the rotational speed of the planet carrier of the rotational speed of the second input shaft. The coolant pump, however, is driven at a speed which corresponds to the speed of the output shaft and thus the speed of the ring gear. The term "connection" is understood to mean here in general a direct mutual or mutual coupling, so that the rotational speeds of the elements connected to one another always coincide.

In the described embodiment, by means of the clutch in the at least one operating state, the sun gear can be directly coupled to the planet carrier, so that they rotate together at the same speed. So there is also an immediate coupling between the first and the second drive unit. By setting sun gear and planet carrier against each other and the planet gears no longer run on the sun gear or the ring gear. Rather, the ring gear is fixed by the coupling of the input shafts with each other with respect to the sun gear and the planet carrier, so that in the one operating state, the output shaft has the same speed as the first and the second input shaft. In this way, the friction losses of the planetary gear in the at least one operating state can be significantly reduced, which positively influences the performance.

A development of the invention provides that in a first of several operating states, the input shafts are coupled directly only indirectly via the planetary gear and in a second of the operating states. As already described above, in the at least one operating state - which is part of the plurality of operating states - the input shafts are to be coupled directly to one another. This at least one operating state corresponds to the aforementioned second of the operating states. In contrast, in a first of the operating states, the input shafts are intended to be coupled together only indirectly via the planetary gearing. The clutch is therefore not used in the first of the operating states to couple the input shafts together, but rather to release them. In this way, the coolant delivery device can be operated over a wide power range, wherein in the second of the operating conditions, the friction losses are reduced. For this reason, the coolant delivery device is preferably operated in this operating state.

A development of the invention provides that in a third of the operating states, the input shafts are coupled only indirectly via the planetary gear and the first input shaft is fixed by means of the coupling. The third of the operating states thus initially corresponds to the first of the operating states, in contrast to this now the first input shaft is to be fixed by means of the clutch. For example, the clutch connects the first input shaft to a stationary element and operates accordingly as a brake or parking brake. In the third of the operating states, the first input shaft is intended to be completely set; the clutch thus does not allow any rotational movement of the first input shaft. In the third of the operating states, the driving of the coolant pump takes place solely with the aid of the second drive unit, because the first input shaft and the first drive unit are fixed with the aid of the clutch.

A development of the invention provides that the planet carrier is operatively connected by means of a belt drive with the second drive unit. For example, a support surface for a traction means of the belt drive is formed on the planet carrier. The first drive unit, however, is preferably rigidly connected to the first input shaft.

A development of the invention provides that the first drive unit is an electric machine and the second drive unit is an internal combustion engine. The coolant delivery device is usually associated with the internal combustion engine or a drive device having this. The coolant conveyor serves to convey coolant, which serves to cool the internal combustion engine. The internal combustion engine is usually set to a desired speed and / or a desired torque, the former resulting from a default speed and the latter from a default torque. The default speed and / or the default torque are determined by a driver of a motor vehicle, which has the drive device, and / or a driver assistance system assigned to the motor vehicle. The speed of the second drive unit is therefore not tuned to the requirements of the coolant conveyor. In contrast, the electric machine can be adjusted so that the coolant conveyor is operated at the desired power. The electric machine can be adjusted accordingly for controlling and / or regulating the power of the coolant pump.

The coolant conveyor is part of a drive device which has the internal combustion engine. In this respect, the invention also relates to a drive device with a (second) drive unit, preferably designed as an internal combustion engine, wherein the drive device or the internal combustion engine is assigned a coolant delivery device according to the above explanations.

The invention further relates to a method for operating a coolant delivery device, in particular according to the preceding embodiments, wherein the coolant delivery device comprises a coolant pump which is drivable via a planetary gear from a first and a second drive unit, wherein the planetary gear via a first input shaft for the first drive unit and has a second input shaft for the second drive unit. It is provided that the input shafts are coupled directly to one another via a coupling in at least one operating state. The coolant delivery device can be developed in accordance with the above statements. As already stated above, the coupling serves to directly couple the input shafts in the at least one operating region.

A development of the invention provides that in a first of the operating states, the input shafts are coupled directly only indirectly via the planetary gear and in a second of the operating states. Such an approach has already been discussed above. The second of the operating states corresponds to the at least one operating state in which the input shafts are directly coupled to one another by means of the clutch. In contrast, in the first of the operating states, the input shafts may have different rotational speeds and are coupled to one another only via the planetary gearing.

A development of the invention provides that in a third of the operating states, the input shafts are coupled only indirectly via the planetary gear and the first input shaft is fixed by means of the clutch. While in the first of the operating conditions, the first input shaft is rotatable, it should be fixed in the third of the operating states by means of the clutch. The input shafts are coupled only indirectly via the planetary gear analogous to the first of the operating states.

A development of the invention provides that in the first of the operating states only one of the drive units or both drive units and / or in the second and / or the third of the operating states, only the second drive unit is operated / are. In the first of the operating states, in which the input shafts are coupled to each other only indirectly via the planetary gear and the first input shaft not fixed by means of the clutch, so is rotatable, only one of the drive units or both drive units can be used simultaneously for driving the coolant pump. In the second and / or third of the operating states, on the other hand, it is intended to operate only the second drive unit while the first drive unit is deactivated. In particular, in the second of the operating states, however, it may be provided that the first input shaft and thus the first drive unit are driven by the second drive unit and are thus in rotational movement.

Figur 1

einen Längsschnitt durch eine Kühlmittelfördereinrichtung mit einer Kühlmittelpumpe und einem Planetengetriebe,

Figur 2

eine schematische Darstellung der Kühlmittelfördereinrichtung in einem ersten Betriebszustand,

Figur 3

die schematische Darstellung der Kühlmittelfördereinrichtung in einem zweiten Betriebszustand,

Figur 4

die schematische Darstellung der Kühlmittelfördereinrichtung in einem dritten Betriebszustand und

Figur 5

ein Diagramm, in welchem die Leistung der Kühlmittelpumpe für die Betriebszustände über einer Drehzahl aufgetragen ist.

The invention will be explained in more detail with reference to the embodiments illustrated in the drawings, without any limitation of the invention. Showing:

FIG. 1

a longitudinal section through a coolant conveyor with a coolant pump and a planetary gear,

FIG. 2

a schematic representation of the coolant conveyor in a first operating state,

FIG. 3

the schematic representation of the coolant conveyor in a second operating state,

FIG. 4

the schematic representation of the coolant conveyor in a third operating state and

FIG. 5

a diagram in which the performance of the coolant pump for the operating conditions is plotted against a speed.

The FIG. 1 shows a cross section through a coolant conveyor 1 with a coolant pump 2, which consists essentially of an impeller 3 and a coolant regulator 4. With the latter, the flow rate of the coolant through the coolant pump 2 can be controlled and / or regulated, for example by a cross-section adjustment become. The impeller 3 of the coolant pump 2 can be driven via a planetary gear 5 by a first drive unit 6 and a second drive unit (not shown). For this purpose, the planetary gear 5 has a first input shaft 7 for the first drive unit 6 and a second input shaft 8 for the second drive unit. The first drive unit 6 is directly coupled to the first input shaft 7. The second drive unit is connected via a belt drive 9 to the second input shaft 8. For this purpose, a region of the second input shaft 8 forms a bearing surface 10 for a belt 11, for example a drive belt.

The first input shaft 7 is connected directly to a sun gear 12 of the planetary gear 5. In contrast, the second input shaft 8 is directly coupled to a planet carrier 13 or formed by this. At the planet carrier 13, a plurality, in particular three, planetary gears 14 are rotatably mounted, so that via the planet gears 14, an operative connection between the sun gear 12 and a ring gear 15 of the planetary gear 5 is made. The ring gear 15 is connected via an output shaft 16 of the planetary gear 5 to the coolant pump 2 and the impeller 3, respectively. The planetary gear 5 is arranged in a housing 17. In this, both the second input shaft 8 and the planet carrier 13 via a bearing 18 and the ring gear 15 and the output shaft 16 are mounted on a bearing 19. Also between the first input shaft 7 and the second input shaft 8, a bearing 20 is provided. The bearings 18, 19 and 20 are preferably designed as rolling bearings. In order to seal the planetary gear 5 with respect to an environment of the housing 17, there is also at least one seal 21, in particular in the form of a sealing ring.

Between the input shafts 7 and 8, a clutch 22 is provided. This can be brought by means of an adjusting device 23 in at least three operating states. The clutch 22 is made up of a slider 24 and a slider lower piece 25 and at least one synchronizer ring 26 (here: two synchronizer rings 26) and one or more friction rings 27 together. In the present embodiment, each synchronizer ring 26 is associated with a friction ring 27. The slider lower piece 25 is rotatably coupled to the first input shaft 7. The slider 24 is connected at the same time rotationally rigidly connected to the slide lower piece 25, but axially displaceably mounted with respect to a rotation axis 28 of the planetary gear 5. By axially displacing the slide 24, the clutch 22 or the coolant delivery device 1 can thus be brought into the various operating states. In a first of the operating states, which in the FIG. 1 is shown, the slider 24 is in the middle, so that the input shafts 7 and 8 are each rotatably coupled and only via the planetary gear 5 with each other. In particular, in a second of the operating conditions (in which the slider 24 is disengaged to the left), it is provided that the input shafts 7 and 8 are directly coupled together. In this second operating state, therefore, the input shafts 7 and 8 have the same speed. In a third of the operating states, in which the slider 24 is displaced to the right, the first input shaft 7 should be fixed, so that no more rotational movement is possible. At the same time, however, the input shafts 7 and 8 are in turn coupled to each other only via the planetary gear 5.

The various operating states are described below on the basis of FIGS. 2, 3 and 4 received. The FIG. 2 shows the first of the operating states. It is clear that the slider 24 is in a neutral position, so that the input shafts 7 and 8 are both freely movable, as well as only coupled to each other via the planetary gear 5. In the first operating state, for example, the coolant pump 2 can be operated solely by means of the first drive unit 6. The maximum volume delivered by the coolant pump 2 is thus predetermined by the electric machine 6. In this way, for example, a running after the coolant pump 2 can be realized after deactivation of the internal combustion engine. Such a wake is important so that no local boiling points in a cooling circuit, not shown here, which is acted upon by means of the coolant pump 2 with coolant, may arise. The maximum volume flow is independent of a speed of the internal combustion engine and only dependent on the maximum power of the electric machine 6.

Alternatively, the coolant pump 2 can be operated both with the electric machine 6 and with the internal combustion engine. In a lower speed range of the internal combustion engine, there is a desire, especially at low ambient temperatures, for an increase in the volume flow in order to meet requirements, for example, of a heating system. In this case, the electric machine 6 may be used in addition to the internal combustion engine for driving the coolant pump 2. Thus, a larger volume flow can be realized. Likewise, the electric machine 6 can be switched on at high load and low speed of the internal combustion engine in order to increase the volume flow which is conveyed by means of the coolant pump 2. Consequently, the internal combustion engine can be optimally cooled even in a lower speed range. A power withdrawal of the internal combustion engine due to a low volume flow is not necessary. Finally, the coolant pump 2 can be operated exclusively by means of the internal combustion engine. If the internal combustion engine is in operation, the second input shaft 8 is permanently driven. Depending on the power distribution in the planetary gear 5, the electric machine 6 can be used as a generator in the first operating state, for example, to supply power to the power grid.

The FIG. 3 illustrates the second of the operating states. In this, the input shafts 7 and 8 are directly coupled with each other, so that they have the same speed. In this case, the sun gear 12 is rotatably connected to the planet carrier 13. This results in a block circulation of the planetary gear 5, in which the input shafts 7 and 8 and the output shaft 16 rotate at the same speed. The driving of the coolant pump 2 takes place solely with the aid of the internal combustion engine, ie via the second input shaft 8. Thus, the maximum achievable volume flow is lower than in the first of the operating states, but sufficient for most purposes. Due to the lower volume flow, the required drive power is also lower. Due to the block revolution of the planetary gear 5 eliminates rotational movements or the rolling movements of the planetary gears 14. In this way, friction losses are reduced in the planetary gear 5, resulting in a more favorable performance in terms of acoustics, heat generation and wear.

The FIG. 4 shows the coolant conveyor 1 in the third of the operating conditions. In this, the first input shaft 7 is fixed in rotation, for example, fixed relative to the housing 17. The electric machine 6 can no longer be used to operate the coolant pump 2. There is a fixed gear ratio of the planetary gear 5 between the second input shaft 8 and the output shaft 6 before. In the third operating state, the heat generated by this is to be removed at high load and high speed of the internal combustion engine.

The FIG. 5 shows a diagram in which the maximum power P of the coolant pump 2 is plotted against the rotational speed n of the internal combustion engine. In this case, the courses 29 and 30 in the first of the operating states, the course 31 in the second of the operating states and the course 32 in the third of the operating states are maximally achievable. The curve 29 shows the maximum power when the coolant pump 2 is operated in the first of the operating states exclusively by means of the electric machine 6. The maximum power is therefore independent of the speed of the internal combustion engine. The curve 30 describes the maximum power P when the coolant pump 2 is driven in the first of the operating states with both the electric machine 6 and the internal combustion engine. The smallest value of the maximum power P thus corresponds to the maximum power of the electric machine 6, while the portion of the maximum power provided by the internal combustion engine is dependent on its speed. In the second of the operating states, in which the input shafts 7 and 8 are coupled directly to each other by means of the clutch 22, the lowest maximum power is present, which is also dependent on the rotational speed of the internal combustion engine. In this way, if only a small volume flow of the coolant by the coolant pump 2 must be promoted to sufficiently cool the engine and / or supply additional elements with coolant, the power of the coolant pump 2 and thus the power loss can be significantly reduced. Accordingly, a more favorable performance is achieved. In the third of the operating states, the first input shaft 7 is fixed, for example, relative to the housing 17. This results in the course 32, which has the characteristic of a known from the prior art coolant conveyor 1.

LIST OF REFERENCE NUMBERS

1

Coolant conveyor

2

Coolant pump

3

impeller

4

Thermostat

5

planetary gear

6

1st drive unit

7

1. input shaft

8th

2nd input shaft

9

belt drive

10

bearing surface

11

endless

12

sun

13

planet carrier

14

planet

15

ring gear

16

output shaft

17

casing

18

camp

19

camp

20

camp

21

poetry

22

clutch

23

locking device

24

pusher

25

Slide lower joint

26

synchronizer ring

27

friction ring

28

axis of rotation

29

course

30

course

31

course

32

course

Claims (10)

1. Coolant delivery device (1) comprising a coolant pump (2) which is drivable via a planetary gear set (5) by a first and a second drive unit (6), the planetary gear set (5) having a first input shaft (7) for the first drive unit (6) and a second input shaft (8) for the second drive unit, characterised by a coupling (22) by means of which the input shafts (7, 8) are directly coupled to each other in at least one operating state.
2. Coolant delivery device according to claim 1, characterised in that the planetary gear set (5) has a sun gear (12), a ring gear (15) and a planet carrier (13) comprising at least one planetary gear (14) producing an operative connection between the sun gear (12) and the ring gear (15), the sun gear (12) being connected to the first input shaft (7), the planet carrier (13) being connected to the second input shaft (8) and the coolant pump being connected to an output shaft (16) connected to the ring gear (15).
3. Coolant delivery device according to either of the preceding claims, characterised in that the input shafts (7, 8) are coupled to each other merely indirectly via the planetary gear set (5) in a first of a plurality of operating states and directly in a second operating state.
4. Coolant delivery device according to any of the preceding claims, characterised in that, in a third operating state, the input shafts (7, 8) are merely indirectly coupled via the planetary gear set (5) and the first input shaft (7) is fixed by means of the coupling (22).
5. Coolant delivery device according to any of the preceding claims, characterised in that the planet carrier (13) is operatively connected by means of a belt drive (9) to the second drive unit.
6. Coolant delivery device according to any of the preceding claims, characterised in that the first drive unit (6) is an electric machine and the second drive unit is an internal combustion engine.
7. Method for operating a coolant delivery device (1), in particular according one or more of the preceding claims, the coolant delivery device (1) having a coolant pump (2) which is drivable via a planetary gear set (5) by a first and a second drive unit (6), the planetary gear set (5) having a first input shaft (7) for the first drive unit (6) and a second input shaft (8) for the second drive unit, characterised in that the input shafts (7, 8) are directly coupled to each other via a coupling (22) in at least one operating state.
8. Method according to claim 7, characterised in that the input shafts (7, 8) are coupled to each other merely indirectly via the planetary gear set (5) in a first operating state and directly in a second operating state.
9. Method according to any of the preceding claims, characterised in that, in a third operating state, the input shafts (7, 8) are merely indirectly coupled via the planetary gear set (5) and the first input shaft (7) is fixed by means of the coupling (22).
10. Method according to any of the preceding claims, characterised in that only one of the drive units (6) or both drive units (6) is/are operated in the first operating state, and/or only the second drive unit (6) is operated in the second and/or third operating state.

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