EP3224484A1

EP3224484A1 - Cooling device for a hydraulic assembly and use of a cooling device

Info

Publication number: EP3224484A1
Application number: EP15798064.0A
Authority: EP
Inventors: Andreas Guender
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2014-11-25
Filing date: 2015-11-20
Publication date: 2017-10-04
Anticipated expiration: 2035-11-20
Also published as: JP2017538899A; JP6570635B2; DE102014223947A1; EP3224484B1; WO2016083249A1; CN107002712A

Abstract

The invention relates to a cooling device for a hydraulic assembly which has a container for hydraulic oil. There is a heat pipe for cooling the container. Hydraulic oil in the container flows approximately in a straight line from an inlet to an outlet. The at least one heat pipe is arranged between the inlet and the outlet.

Description

Cooling device for a hydraulic unit and use of a cooling device

description

The invention relates to a cooling device for a hydraulic unit for cooling a container for hydraulic oil of the hydraulic unit. Furthermore, the invention relates to a use of the cooling device. For example, it is known from the prior art that pressure medium or hydraulic oil is conveyed from a container via a hydraulic pump, such as an external gear pump, which can be driven by a variable-speed motor. On the output side of the pump, the pressure medium can be diverted via a throttle, which can also serve to set a minimum speed of the pump. Pressure fluid branched off via the throttle can give off heat to an environment via a radiator, which is cooled by air from a fan. In addition, a leakage of the pump can

Radiator are supplied. The disadvantage here is that the throttle to hydraulic

Losses leads, which in turn lead to a waste heat. A magnitude of a volume flow through the radiator is further disadvantageous depending on a system pressure

output side of the pump, which is why there is no constant cooling capacity of the pressure medium. In addition, a cooling of the pressure medium by the radiator is possible only during operation of the pump.

Furthermore, it is known from the prior art, pressure medium from the container via two pumps (double pump) to promote, which are driven jointly by a variable speed motor. One of the pumps can in this case promote a volume flow for a cooling circuit, which may optionally have a filter. The disadvantage here is that for the cooling thus an additional pump is required, resulting in a higher

device complexity and thus in particular to higher Production costs leads. Furthermore, the additional pump is an additional sound source. A piping effort is disadvantageous also comparatively high, which also increases the risk of leakage. Furthermore, the

Failure probability increase by the use of the double pump, since experience shows that the pump is the most wear-prone component in a hydraulic system. In addition, the additional pump leads to hydraulic losses and thus to an additional

Heat stress. Since the pumps are coupled together, the volume flow of the cooling circuit is dependent on the volume flow of a primary circuit of the first pump.

In addition, cooling is also disadvantageous only during operation of the pumps.

Apart from the publications JP 58196301 A and JP 61 1 161 12 A cooling devices for containers are known, which have heat pipes in the form of heat pipes.

In contrast, the present invention seeks to provide a cooling device for a hydraulic unit, which can cool pressure fluid outside of an operation of the hydraulic unit or during a standstill of the hydraulic unit, has improved efficiency compared to the prior art and has a low space requirement. Furthermore, it is an object of the invention to provide an advantageous use of a cooling device according to the invention.

The object with regard to the cooling device is achieved according to the features of

Claim 1 and with regard to the use according to the features of claim 15.

Other advantageous developments of the invention are the subject of further

Dependent claims.

According to the invention, a cooling device for a hydraulic unit is provided. The cooling device in this case has a container or tank for a hydraulic oil of the hydraulic unit. The container may have an inlet and a drain, which may be configured as a return line and suction line. Advantageously, the

Cooling device at least one heat pipe, preferably three heat pipes, wherein the heat pipe is immersed with a pipe section in the container. Thus, it can dissipate heat from the hydraulic oil. This solution has the advantage that such a cooling device can cool hydraulic oil even during a standstill of the hydraulic unit by dissipating heat via the at least one heat pipe. In addition, the cooling device has an improved efficiency compared to the prior art and has a smaller space requirement.

The heat pipe is, for example, a heat pipe or a two-phase thermosyphon. The heat pipe has, for example, a refrigerant which evaporates at a point to be cooled, whereby heat is dissipated as heat of vaporization. The gaseous coolant can then be distributed in the heat pipe and precipitate on a cooled section (heat sink) on a tube inner wall. Due to gravity or capillary action, the coolant may then flow back to the cooling point. The at least one heat pipe preferably protrudes with a further pipe section from the container in order to dissipate the heat to the outside.

The at least one heat pipe can be arranged in the flow path of the hydraulic oil between the inlet and the outlet. Preferably, the inlet, the drain and the at least one heat pipe are arranged approximately in a row. By the arrangement of the heat pipe in said flow path, this is advantageously from

Hydraulic oil, which flows from the inlet to the outlet, flows around during operation of the hydraulic unit. In device-technically simple manner, the flow path may preferably extend between the inlet and the drain in about one direction, whereby no or no major changes in direction of the flow path are provided and thus a simple geometric design, in particular of the container is possible and flow losses are minimized.

In a further embodiment of the invention, two or more heat pipes are provided. These are preferably arranged such that, viewed in the direction of the flow path, they are not arranged in series one behind the other. Thus, the heat pipes do not shadow each other, resulting in more heat from the hydraulic oil to the heat pipes can be performed. Preferably, the two or more heat pipes are arranged approximately transversely to the flowpath or provided in a common plane which is angled to the direction of the flowpath. The heat pipes can preferably extend approximately parallel to one another. The heat pipes protruding from the container may also extend substantially in a same direction, this being approximately a vertical direction.

For improved heat supply and / or heat removal, a cooling structure may be provided on the at least one heat pipe. The cooling structure is preferably at least thermally connected to the heat pipe. It is conceivable that the cooling structure is also mechanically connected to the at least one heat pipe or is designed in one piece with this. It is conceivable to have a cooling structure inside the container and a

Provide cooling structure outside the container. The cooling structure has, for example, a plurality or multiplicity of lamellae, which may be formed as a lamella packet.

For example, the slats extend approximately perpendicular to the at least one

Heat pipe. These can be arranged approximately parallel to each other. Two or more heat pipes can share a respective cooling structure.

A size of the cooling structure in the container corresponds approximately to a flow cross section of the flow path of the container or the cross section of the container in

Flow direction. Thus, fins of the heat pipe or the heat pipes within the container can enforce about the full cross-section of the container. Due to the geometric arrangement of the inlet on one side of the plate pack and the drain on the other side of the plate pack, a volume flow through the plate pack can be performed. As a result, a heat transfer from the hydraulic oil to the fins and thus in turn increased to the heat pipe or the heat pipes.

The cooling structure may be provided on the pipe section of the at least one heat pipe provided inside the container. Additionally or alternatively, the

Cooling structure may be provided on the pipe section of the at least one heat pipe provided outside the container.

The cooling structure may be configured to promote a degassing process of the hydraulic oil. The at least one heat pipe and / or the cooling structure can be cooled outside the container by forced convection, in particular by a fan. Alternatively or additionally, the at least one heat pipe and / or the cooling structure outside the container can be cooled by a heat exchanger. The heat exchanger can then be flowed through, for example, by a stream of material (cooling water). Thus, the

Heat exchanger have a cooling water circuit. Alternatively or additionally, the heat exchanger may also be connected to a housing, in particular a machine housing, in particular of the hydraulic unit, thermally and / or mechanically (in particular directly) in order to release heat to the housing.

A flow cross section of the flow path is advantageously reduced in the manner of a throttle in the region of the at least one heat pipe and / or in the region of the cooling structure. This is advantageous if the heat pipe and / or the cooling structure (plate pack) does not completely pass through the cross section of the container, with which the hydraulic oil can then be forced to the heat pipe and / or the cooling structure. In addition, by the throttle-like reduction, a flow rate of the hydraulic oil can be increased, whereby an improved flow around the heat pipe and / or the cooling structure is made possible.

At least the one heat pipe and / or the cooling structure may be arranged approximately in the region of the narrowest cross section of the container.

The reduction of the flow cross-section is done for example by a

Flow guidance. This is preferably a ramp or a partition that reduces the flow cross-section. If a ramp is provided, it may be angled, for example, starting from a container bottom, in particular extending away in the direction of flow. The reduction of the flow cross-section is preferably continuous, whereby the flow characteristics of the hydraulic oil are improved.

In a further embodiment of the invention, the hydraulic oil from the drain over a

Hydromachine conveyed, which is drivable by a drive unit. The drive unit may have its own cooling device, the device technology simply additional is used for cooling the at least one heat pipe and / or the cooling structure. Preferably, the cooling device of the drive unit is a fan whose air flow is used for cooling. Thus, by geometric arrangement of the disk set outside of the container behind the engine fan, an increase in the heat transfer to the environment by the air volume flow generated thereby.

Advantageously, the drive unit and the hydraulic machine can then form a motor-pump unit or a motor-pump group. Preferably, an arrangement with the cooling device according to the invention and the motor-pump unit can then be provided. The motor-pump unit is preferably arranged directly or adjacent to the at least one outer heat pipe and / or its outer cooling structure.

Advantageously, in addition to the at least one heat pipe for the container, a further heat pipe can be provided for a further component of the hydraulic unit. The further heat pipe can then at least with a pipe section adjacent to

Pipe section of the at least one heat pipe of the container may be arranged. The

Heat pipes can then combine both the heat of the container and the heat of another component or other components, such as the drive unit or other "hotspots." This can cause a temperature of the entire

Hydraulic unit to be kept constant and / or heat dissipated together. Thus, with this concept, the heat energy can be bundled and alternatively used for further processes. The heat pipes of the container and at least one other component are

preferably cooled together.

As already explained above, the waste heat of at least one heat pipe of the container and / or the component can be provided for at least one further process.

The heat pipes for the container together with the cooling structure are preferably designed such that an approximately constant temperature is provided on both heat receiving surfaces and on heat emitting surfaces. As a result, a temperature difference to the hydraulic oil or the environment on an entire area about the same be great. As a result, a heat-emitting capacity for the same area is comparatively high, and the cooling device can be made more compact.

In an advantageous use of the cooling device, it is intended to use this for a hydraulic unit, which has a comparatively low cooling requirement and may be a so-called "small aggregate". Preferably, the hydraulic unit or the container of the hydraulic unit has a cooling capacity of max. 1000 watts, preferably of max. 300 to 500 watts. When using the cooling device for small aggregates, it is thus advantageously possible to resort to products from the computer industry, since, for example, modern graphics cards have a similar cooling performance.

For example, heat pipes from the computer industry are technically advanced and usually inexpensive.

Other advantageous development are the subject of further subclaims.

In the following, preferred embodiments of the invention will be described with reference to FIG

Drawings explained in more detail. Show it:

FIG. 1 shows a schematic illustration of a cooling device according to a first exemplary embodiment,

FIG. 2 shows a schematic illustration of the cooling device according to a second exemplary embodiment,

3 is a schematic representation of the cooling device according to a third embodiment,

FIG. 4 shows a schematic representation of the cooling device according to a fourth exemplary embodiment,

Figure 5 is a schematic representation of the cooling device according to a fifth embodiment and

6 shows a schematic representation of a temperature distribution of the cooling device.

According to FIG. 1, the cooling device 1 has a container 2 for hydraulic oil. Via an inlet 4 in the form of a supply line hydraulic oil 6 is supplied from a hydraulic unit to the container 2. Via a drain 8 in the form of a drain line hydraulic oil 10 is then led out of the container 2. According to the embodiment in Figure 1 are the Inlet 4 and the drain 8 arranged approximately at a parallel distance from each other. The container 2 has an approximately cuboid configuration. Between the inlet 4 and the outlet 8 three heat pipes 12, 14 and 16 are provided. These are designed approximately rod-shaped and immersed with a pipe section 18 in the container 2 and collar with a further pipe section 20 from the container 2. The heat pipes 12 to 16 extend approximately in a vertical direction and are arranged at a parallel distance from each other. The heat pipes 12 to 16 extend in this case approximately in a common plane. At the inner

Pipe sections 18 of the heat pipes 12 to 16 is a cooling structure in the form of a

Disc packs 22 arranged. This is arranged together with the heat pipes 12 to 16 in the plane. The disk pack 22 has a plurality of approximately in

Parallel distance to each other extending lamellae. The lamellae extend approximately in the horizontal direction.

A flow path 24 within the container 2 leads from the inlet 4 to the outlet 8 approximately in a single direction. The disk pack 22 is then disposed within the flow path 24. According to Figure 1, the plane in which the plate pack 22 and the heat pipes 12 to 16 are arranged, approximately transversely to the flow path 24. Das

Disk pack 22 extends approximately over an entire cross-section of the container 2, so that it flows through or flows around the entire of the inlet 4 to the outlet e flowing hydraulic oil. A heat 26 can thus be supplied to the heat pipes 12 to 16 directly or via the disk pack 22 from the pressure medium in the container 2.

The pipe sections 20 outside the container 2 is also associated with a cooling structure in the form of a disk set 28. This is according to Figure 1 according to the

Disc pack 22 is formed. A heat 30 can then be delivered from the pipe sections 20 of the heat pipes 12 to 16 directly via the disk pack 28 to an environment. In addition, a fan 32 is provided, which has a flow through the

Disc packs 28 increased with air.

According to Figure 1, thus, the container 2 is shown, whose cross section is penetrated by the plate pack 22. The plate pack 22 is in this case thermally connected to a plurality of heat pipes 12 to 16. The sequence 8 is here on one side of the

Disc packs 22 and the inlet 4 on the other side. This will be during the Operation by the self-adjusting volume flow of the hydraulic oil in the container 2, the heat transfer from the hydraulic oil to the inner plate pack 22 increases. The heat pipes 12 to 16 then transport the heat energy to the outer plate pack 28, in which case the heat transfer to the ambient air by means of the fan 32 is increased.

2, a cooling device 34 is shown. In contrast to Figure 1, this has no fan 32 and no outer plate pack 28. Instead, one is

Heat exchanger 36 is provided. This is the ends of the heat pipes 12 to 16 arranged. In the heat exchanger, the heat energy, for example, via a

Cooling water circuit or delivered to a thermally inert mass of a machine housing. Here, the heat energy of the hydraulic unit is bundled in one area and can be made available for further processes if necessary, especially when using several hydraulic units. According to FIG. 3, a cooling device 38 has a reduced inner disk set 40 in comparison with the embodiment in FIG. 1. Furthermore, the heat pipes 12 to 16 in the container 2 are shortened. Thus, the plate pack 40 with the heat pipes 12 to 16 within the container 2 a smaller cross section and thus does not penetrate the entire cross section of the container 2. To increase the heat transfer in this case a flow guide 42 is provided. This prevents the hydraulic oil from flowing past the disk pack 40 or the heat pipes 12 to 16. Furthermore, the heat transfer is increased by a higher flow rate of the hydraulic oil. The flow guide 42 is designed as a ramp which extends from the container bottom 44 toward the disk pack 40 or the heat pipes 12 to 16. In the narrowest cross section of the container 2, the plate pack 40 is then arranged with the heat pipes 12 to 16.

In FIG. 4, in contrast to FIG. 1, the cooling device 46 has no fan 32.

Instead, a motor fan 48 of a motor 50 is used. The motor fan 48 thus serves to cool the motor 50 and to cool the outer plate pack 28 with the heat pipes 12 to 16. The motor 50, a pump 52 is driven. This promotes hydraulic oil through the outlet 8 from the container 2. According to Figure 4, the motor 50 is thus arranged or mounted with the pump 52, which form a motor-pump unit, directly adjacent to the outer plate pack 28, and one of the motor fan 48th Volume flow generated can then increase the heat transfer to the disk pack 28 and to the heat pipes 12 to 16.

A cooling device 54 in FIG. 5 has additional heat pipes 56 and 58 in addition to the heat exchanger 36, see FIG. The heat pipe 56 is used to cool the motor 50 and the heat pipes 58 for cooling the pump 52. In addition, further heat pipes can be provided for more to be cooled sections or components of a hydraulic unit. The heat pipes 56, 58 and 12 to 16 are bundled together in the heat exchanger 36 and can be selectively cooled by a cooling water circuit or give off heat to the thermally inert mass of the machine housing. The heat energy is thus bundled and can be used as needed for further processes.

The heat pipes 12 to 16 and / or 56, 58 and / or the cooling structure can be components from the computer industry. The heat pipes 12 to 16 with their cooling structure are designed, for example, for cooling capacities between 300 to 500 watts.

In Figure 6 is an example of a temperature distribution of a plate package 60 with

Heat pipes shown. It can be seen that a temperature of the disk pack 60 is in an approximately equal temperature range. Thus, with an approximately same

Temperature gradients are emitted and / or absorbed over the entire disk pack 60 heat.

Disclosed is a cooling device for a hydraulic power unit, which has a container for

Has hydraulic oil. For cooling the container, a heat pipe is provided. Hydraulic oil in the container flows approximately linearly from an inlet to a drain. Between the inlet and the drain then the at least one heat pipe is arranged.

LIST OF REFERENCES

1 cooling device

2 containers

4 inlet

6 hydraulic oil

8 expiration

10 hydraulic oil

12 heat pipe

14 heat pipe

16 heat pipe

18 pipe section

20 pipe section

22 plate pack

24 flow path

26 heat

28 plate pack

30 heat

32 fans

34 cooling device

36 heat exchangers

38 cooling device

40 plate pack

42 flow guidance

44 container bottom

46 cooling device

48 engine fan

50 engine

52 pump

54 cooling device

56 heat pipe

58 heat pipe

60 disc pack

Claims

claims

1. Cooling device for a hydraulic unit with a container (2) for hydraulic oil, which has an inlet (4) and a drain (8), wherein at least one heat pipe (12, 14, 16) is provided, which is connected to a pipe section (20). immersed in the container (2) to dissipate heat from the hydraulic oil.

2. Cooling device according to claim 1, wherein the at least one heat pipe (12, 14, 16) in the flow path (24) of the hydraulic oil between the inlet (4) and the outlet (8) is arranged.

3. Cooling device according to claim 2, wherein the flow path (24) extends between the inlet (4) and the outlet (8) approximately in one direction.

4. Cooling device according to one of claims 1 to 3, wherein two or more

Heat pipes (12, 14, 16) are provided, which are not arranged in series in the direction of the flow path (24) seen.

5. Cooling device according to one of the preceding claims, wherein on the at least one heat pipe (12, 14, 16), a cooling structure (22, 28) is provided.

6. Cooling device according to claim 5, wherein a size of the cooling structure (22) in the container (2) corresponds approximately to a flow cross-section of the container (2).

7. Cooling device according to claim 5 or 6, wherein the cooling structure (22) at the within the container (2) provided in the pipe section (18) of the at least one

Heat pipe (12, 14, 16) is provided and / or wherein the cooling structure (28) on the outside of the container (2) provided pipe section (20) of the at least one

Heat pipe (12, 14, 16) is provided.

8. Cooling device according to one of claims 5 to 7, wherein the cooling structure (22) is designed such that it promotes a degassing process of the hydraulic oil.

9. Cooling device according to one of the preceding claims, wherein the at least one heat pipe (12, 14, 16) outside the container (2) is cooled by forced convection.

10. Cooling device according to one of the preceding claims, wherein the at least one heat pipe (12, 14, 16) outside the container (2) by a heat exchanger (36) is cooled.

1 1. A cooling device according to one of the preceding claims, wherein a

Flow cross-section of the container (2) in the region of the at least one heat pipe (12, 14, 16) is reduced throttle-like.

12. Cooling device according to one of the preceding claims, wherein hydraulic oil from the outlet (8) via a hydraulic machine (52) is conveyed, which by a drive unit (50) can be driven, wherein the drive unit (50) has a cooling device, in addition to the cooling of at least one heat pipe (12, 14, 16) is inserted.

13. Cooling device according to one of the preceding claims, wherein at least one further heat pipe (56, 58) for a further component (50, 52) of the hydraulic unit is provided, wherein the at least one further heat pipe (56, 58) with a

Pipe section adjacent to the outer pipe section (20) of the at least one

Heat pipe (12, 14, 16) of the container (2) is arranged.

14. Cooling device according to one of the preceding claims, wherein the waste heat of at least one heat pipe (12, 14, 16, 56, 58) is provided for at least one further process.

15. Use of the cooling device according to one of the preceding claims for a hydraulic unit, which is designed such that at least the container has a comparatively low cooling requirement, in particular a cooling capacity of max. about 1000 watts, preferably of max. 300 to 500 watts.