Hydrostatic compact unit with cooling

Abstract

Electro-hydraulic compact unit with a drive unit comprising an electric motor (M) and a hydrostatic pump (1), wherein pressure medium can be drawn from a tank (T) of the compact unit via the pump (1), characterized by a cooling device extending into an interior of the tank (T), wherein the cooling device comprises a cooling plate (24) by which the tank (T) is sealed and to which the drive unit is attached, and wherein the cooling device comprises at least one pressure medium heat pipe (146) extending from the interior of the tank (T) to the cooling plate (24), and which is heat-conductingly attached to or penetrates the cooling plate (24).

Description

[0001] The invention relates to a compact unit with cooling according to the preamble of claim 1.

[0002] Prior art provides power units that pump hydraulic oil from a tank to a hydraulic system using a drive unit consisting of an electric motor and a pump. The hydraulic system supplied by the power unit includes a consumer, e.g., a hydraulic cylinder of a machine tool, and control valves.

[0003] Such units require cooling due to their high power density and efficiency. Further reasons for cooling include the fact that various hydraulic components have a maximum permissible temperature of approximately 60-80°C, and that the aging of the hydraulic oil increases with rising temperature.

[0004] It is known to implement cooling using an oil-to-air heat exchanger in the return line from the hydraulic system to the tank. A disadvantage of this method is that the high thermal resistance (primarily determined by the low heat capacity and thermal conductivity of air) between the oil-to-air heat exchanger and the environment, as well as the limitation of the maximum temperature difference by the maximum temperature of the hydraulic oil, means that the cooling capacity of the oil-to-air heat exchanger is only economical for low cooling capacities (<10 kW), as otherwise the cooling surface of the oil-to-air heat exchanger would have to be very large.

[0005] In the prior art, it is known, for example, that hydraulic fluid is drawn from the tank via an external gear pump driven by a variable-speed electric motor. Hydraulic fluid can be diverted from the pump's outlet via a throttle, which can also be used to set a minimum pump speed. The hydraulic fluid diverted via the throttle dissipates heat to the environment through the oil-air heat exchanger, which is additionally cooled by a fan. Additionally, any leakage from the pump can be fed into the oil-air heat exchanger. A disadvantage of this design is that the throttle leads to hydraulic losses, which in turn result in waste heat. Furthermore, the flow rate through the oil-air heat exchanger is disadvantageously dependent on the system pressure at the pump's outlet, meaning that the hydraulic fluid is not cooled constantly. Moreover, such cooling of the hydraulic fluid is only possible while the pump is operating.

[0006] Furthermore, it is known from the prior art to pump hydraulic fluid from the tank using two pumps (dual pump) driven jointly by a variable-speed electric motor. One of the pumps can deliver a flow rate for a cooling circuit. A disadvantage of this is that an additional pump is required for cooling, resulting in more complex equipment. The piping effort is also high, which further increases the risk of leakage. Moreover, the probability of failure can increase with the use of the dual pump, as pumps are known to be a component in a unit or hydraulic system subject to significant wear. In addition, the extra pump leads to hydraulic losses and thus to an additional heat load. Since the pumps are coupled, the flow rate of the cooling circuit depends on the flow rate of the primary circuit of the first pump.Furthermore, the cooling also occurs disadvantageously only during the operation of the pumps.

[0007] Alternatively, an oil-water heat exchanger can be used instead of an oil-air heat exchanger. This cooling concept offers high cooling capacity due to its low thermal resistance. However, a disadvantage is that a complex water cooling circuit may be required, and the maximum cooling capacity is also limited by the maximum oil temperature. Furthermore, the heat energy absorbed by the hydraulic system often needs to be dissipated to the environment via a water-air heat exchanger.

[0008] DE 196 52 706 A1 discloses a hydraulic power unit comprising an electric motor, a hydraulic pump, and an annular cylindrical tank (pressure medium reservoir), wherein the tank surrounds the electric motor. The inner outer wall of the tank surrounds the electric motor and serves as a guide for an airflow passing over the electric motor, thus ensuring both a compact design of the power unit and sufficient cooling of the electric motor via the airflow.

[0009] DE 20 2004 011 911 U1 shows a device for cooling and filtering a circulating fluid and an associated housing.

[0010] According to WO 2010 / 142 631 A2, a vacuum pump in a pumping chamber has pumping elements. One of the pumping elements is driven by an electric motor. A frequency converter is provided to change the speed of the electric motor. The frequency converter is located in a frequency converter housing directly connected to the pump housing. An air cooler and a liquid cooler are arranged inside the frequency converter housing to cool the frequency converter.

[0011] DE 10 2008 057 414 B3 discloses a high-performance conveying unit for volatile liquids, the waste heat generated in the area of ​​the electronic power control of an electric motor is transferred into the liquid to be conveyed.

[0012] DE 196 39 098 A1 describes a motor pump with a cooled frequency converter.

[0013] According to DE 41 21 430 C1, a pump unit has an electric motor cooled by a pumped fluid.

[0014] DE 10 2006 045 701 A1 discloses a cooling device and an arrangement with a cooling device, EP 2 478 295 B1 a cooling device for a heat source and DE 10 2007 038 909 A1 a heat guide tube and an arrangement with a heat guide tube.

[0015] In contrast, the invention is based on the objective of creating a compact unit that enables effective cooling with minimal equipment effort, independent of the operating state of the pump.

[0016] This problem is solved by a compact unit with the features of claim 1.

[0017] The claimed electro-hydraulic compact unit has a drive unit comprising an electric motor and a hydrostatic pump, wherein hydraulic fluid is drawn from a tank of the compact unit via the pump. According to the invention, a cooling device is provided for cooling the hydraulic fluid, which extends at least partially into an interior space of the tank to cool the returning hydraulic fluid. The interior space of the tank is understood to be the space containing the fluid. The cooling device has a cooling plate that seals the tank and to which the drive unit is attached. Preferably, the drive unit and the tank are arranged on a first side, in particular the underside, of the cooling plate. This allows the tank to surround the drive unit and reduce its noise emission.Furthermore, according to the second principal variant, the cooling device includes at least one so-called pressure medium heat pipe, which serves to cool the pressure medium and extends from the interior of the tank to the cooling plate. The pressure medium heat pipe is thermally attached to the cooling plate in order to transfer its heat to it, or it penetrates the cooling plate, e.g., to also transfer its heat to another device that is arranged on a second side, in particular the top, of the cooling plate.

[0018] Further advantageous embodiments of the invention are described in the dependent patent claims.

[0019] The cooling device is preferably also used to cool the electric motor and is therefore also in a heat-conducting connection with the electric motor.

[0020] In a first basic variant, the cooling device has a coolant line, in particular a hose or a curved pipe, which is arranged section by section inside the tank to absorb waste heat from the pressurized medium. Furthermore, the coolant line is also in thermally conductive connection with the electric motor in sections.

[0021] It is preferred that the tank is closed by a lid to which the drive unit is attached. In this case, the drive unit and the tank can be arranged on the same first side, particularly the underside, of the lid, so that the tank surrounds the drive unit and reduces its noise emission.

[0022] In a further development, a heat sink is arranged on a second side of the lid facing away from the tank, in particular on the top side. A frequency converter for the electric motor is thermally attached to this heat sink, and the heat sink is in thermally conductive contact with the coolant line. Preferably, the coolant line penetrates the heat sink.

[0023] In a particularly effective embodiment of the first basic variant, the coolant line is arranged in such a way that the coolant flowing through it first cools the pressure medium, then the electric motor and finally the heat sink and thus the frequency converter.

[0024] To improve heat transfer from the pressure medium to the pressure medium heat pipe, it is particularly preferred if at least one finned assembly is provided in the tank, which is thermally attached to the pressure medium heat pipe. The pressure medium is returned to the tank via the finned assembly.

[0025] In a further development, air cooling is provided for the pressure medium, according to which the pressure medium heat pipe penetrates the cooling plate and is thermally connected to another fin pack, which is arranged on the second side, in particular the top, of the cooling plate, facing away from the tank.

[0026] Preferably, the cooling device also includes at least one so-called motor heat pipe, which serves to cool the electric motor and extends from the electric motor towards the cooling plate. The motor heat pipe is also thermally attached to the cooling plate in order to transfer its heat to it, or it penetrates the cooling plate, e.g., to also transfer its heat to another device that is arranged on the other side, in particular the top, of the cooling plate.

[0027] To optimize the heat transfer from the electric motor to the motor heat pipe, the latter can be inserted into a housing of the electric motor in a heat-conducting manner.

[0028] In a further development, an air cooling system for the electric motor is provided, according to which the motor heat pipe penetrates the cooling plate and is thermally connected to another fin pack, which is arranged on the second side, in particular the top, of the cooling plate, facing away from the tank.

[0029] If at least one support surface or support device (e.g., feet) is arranged adjacent to or on a (lower) area of ​​the tank facing away from the cooling plate, defining a support plane for the compact unit, it is particularly preferred if the heat pipes are arranged approximately perpendicular to this. A perpendicular arrangement optimizes the heat transfer capacity of the heat pipes.

[0030] If the electric motor is electrically supplied and controlled via a frequency converter, in the second principal variant it is particularly preferred if it is attached to the cooling plate on the second side facing away from the tank, in particular on the top side, in a heat-conducting manner.

[0031] In a further training system, liquid cooling is provided for the pressure medium and the electric motor and, if applicable, the frequency converter, according to which a cooling channel is provided in the cooling plate.

[0032] In a further development of the liquid cooling system, the cooling channel extends along a contact area between the frequency converter and the cooling plate and forms a section of a return line for the pressure medium.

[0033] In a preferred embodiment of the water cooling system, it has an inlet connection from which a first section of the cooling channel extends in an outer region of the cooling plate, in particular along an outer circumference of the cooling plate, and with a second section of the cooling channel connected thereto, which is arranged in an inner region of the cooling plate. The two sections can be arc-shaped, in particular approximately circular arc-shaped and concentric to each other.

[0034] In order to first cool the cooler heatpipe with the cooler coolant and then cool the warmer heatpipe with the warmer coolant, it is preferred if the pressure medium heatpipe is attached to or penetrates the cooling plate in the outer area, and if the motor heatpipe is attached to or penetrates the cooling plate in the inner area.

[0035] In an advantageous embodiment of the compact unit, an inner wall and an outer wall of the tank are essentially cylindrical, while the base is annular, and the lid or cooling plate is annular or disc-shaped. The two walls, the base, the lid or cooling plate, and a central axis of the electric motor or drive unit are concentric to each other, and the central axis is approximately perpendicular to the base.

[0036] In a particularly preferred embodiment, several pressure medium heat pipes are evenly distributed around the circumference of the annular tank.

[0037] In a particularly preferred embodiment, several motor heat pipes are evenly distributed around the circumference of the annular or disc-shaped cooling plate.

[0038] In general, heat siphons can also be used instead of the aforementioned heat pipes, since heat is always preferably transported against gravity.

[0039] Several embodiments of a compact unit according to the invention are shown in the drawings. The invention will now be explained in more detail with reference to the figures in these drawings.

[0040] They show Fig. 1 in a perspective exploded view a compact unit according to the invention in a first embodiment, Fig. 2 in a perspective view essential parts of a compact unit according to the invention in a second embodiment, Fig. 3 in a cross-section a cooling plate of the second embodiment according to Fig. 2, Fig. 4 in a perspective longitudinal section a compact unit according to the invention without a tank according to a third embodiment, Fig. 5 in a perspective longitudinal section a compact unit according to the invention without a tank according to a fourth embodiment, Fig. 6 in a perspective view a compact unit according to the invention without tank and housing according to a fifth embodiment, Fig. 7 in a longitudinal section a compact unit according to the invention Fig. 6 and Fig. 8 in a schematic longitudinal section a compact unit according to the invention in a sixth embodiment.

[0041] All in the Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6, Fig. 7 to Fig. The eight embodiments of the compact unit according to the invention shown have an annular, cup-shaped tank T made of plastic, which has a circular cylindrical inner wall 46, a circular cylindrical outer wall 48, and an annular base 42. The tank T encloses a drive unit formed by an upper electric motor M and a lower pump 1. The electric motor M is arranged concentrically with respect to the tank T.

[0042] The pump draws pressure medium, e.g. hydraulic oil, from tank T via a suction line (not shown) and delivers it via a supply line 12 to a high-pressure-side consumer connection 14 (see Fig. 2) The pressure medium flows via a valve to a consumer (both not shown) and back into tank T via a return line 20 of the compact unit. Various cooling devices are provided for the returning pressure medium.

[0043] In the first embodiment according to Fig. In 1, a water cooling system for the pressure medium is implemented. It has two fin packs 144 arranged inside the tank T, the fins of which are approximately semicircular and soldered onto pressure medium heat pipes 146, which are also located largely inside the annular tank T. At the top, the pressure medium heat pipes 146 are inserted into bores in a circular cooling plate 24 and are thermally connected with thermal paste and secured by an interference fit.

[0044] The cooling plate 24 serves as a cover for the tank T. Furthermore, the drive unit is suspended from a central area of ​​the lower side of the cooling plate 24 via its electric motor M. The cooling plate 24 is equipped with a cooling channel 19 (see figure). Fig. 3) equipped for a cooling medium, preferably cooling water, wherein in Fig. Only connections 154 of the cooling channel 19 are visible. The heat energy of the pressure medium is thus absorbed via the fin pack 144, conducted via the pressure medium heat pipes 146 into the cooling plate 24, and there absorbed and transported away by the cooling medium.

[0045] The return line 20 of the pressure medium is located in the cooling plate 24, and the suction line of the pump 1 is in the lower part of the tank T. The fins of the fin pack 144 are slightly inclined and each penetrates almost half the cross-sectional area of ​​the annular tank T. This directs the flow of the returned pressure medium downwards in a spiral pattern during operation. Advantages include the complete utilization of the volume and the prevention of flow short-circuiting between the return line 20 and the suction line. Furthermore, the targeted flow around the fins of the two fin packs 144 reduces the thermal resistance between the pressure medium and the fins, thus increasing the cooling capacity. Additionally, air separation from the pressure medium is promoted by utilizing the density difference between air and the pressure medium.

[0046] The two in Fig. The lamellar packs 144 shown in Figure 1 are not required if the heat transfer from the pressure medium to the pressure medium heat pipes 146 is sufficiently good. In such an embodiment (not shown), the helical flow can be generated, for example, by lamellae or geometries located in the interior of the annular tank T.

[0047] Fig. Figure 2 shows the two lamella packs 144 and the drive unit mounted between them of a second embodiment of the compact unit according to the invention. The difference from the first embodiment is that the electric motor M is also cooled via motor heat pipes 147. For this purpose, the motor heat pipes 147 are inserted into a housing of the electric motor M. Since the cooling plate in Fig. Not shown in Figure 2, the respective upper end sections of four pressure medium heat pipes 146 of one fin pack 144, of four pressure medium heat pipes 146 of the other fin pack 144, and of four motor heat pipes 147 of the electric motor M are visible. All heat pipes 146, 147 penetrate the (in Fig. 2 (not shown) cooling plate 24 and end at their top.

[0048] Since in the lower area of ​​the (in Fig. In the two cup-shaped tanks T (not shown), through whose bottom 42 a base plane is defined, the central heat pipes 146 and the motor heat pipes 147 are aligned perpendicular to this plane, so that the heat pipes 146, 147 are always arranged perpendicular to the Earth's gravity during operation of the compact unit and can optimally transport the heat from bottom to top to the cooling plate 24.

[0049] Furthermore, an electrical conductor 6 is visible, through which the electric motor M is supplied with power. The electrical conductor 6 penetrates the cooling plate 24.

[0050] Fig. Figure 3 shows the cooling plate 24 of the second embodiment according to Fig. 2 in a cross-section (viewed from below). The cooling plate 24 is made of a thermally conductive material such as aluminum and is manufactured using a die-casting process. A pre-formed curved tube, made of, for example, steel, is inserted into the die-casting mold so that it is subsequently located inside the cooling plate 24 and cast in along with it. This forms the cooling channel 19.

[0051] Preferably, the tube forming the cooling channel 19 is shaped and inserted into the mold such that it runs directly alongside the upper end sections of the heat pipes 146, 147. This reduces the thermal resistance at the transition from the heat pipes 146, 147 to the cooling medium, preferably cooling water.

[0052] Preferably, the cooling channel 19 is configured such that the cooling medium first cools the pressure medium heat pipes 146, since the pressure medium must be cooled to approximately 50°C, and then cools the motor heat pipes 147, since the electric motor M must be cooled to approximately 100°C. For this purpose, the cooling channel 19 has a first outer arc-shaped section and a second arc-shaped inner section, viewed in the direction of flow of the cooling medium. A bend in the cooling channel 19 allows the radial connections 154 of the cooling channel 19 to lie next to each other.

[0053] In the third embodiment according to Fig. 4. In addition to the pressure medium and the electric motor M, a frequency converter 2 of the electric motor M is cooled by the cooling medium, preferably cooling water, in which the cooling channel 19 (the inserted tube or bores) of the cooling plate 24 also runs below the frequency converter 2. The frequency converter 2 is preferably thermally connected to the upper surface of the cooling plate 24, facing away from the tank T and the drive unit, by means of a thermal paste.

[0054] In the fourth embodiment according to Fig. The frequency converter 2 is cooled by the returning pressure medium. More precisely, the return line 20 is connected to the tank T via a channel 22 located inside the cooling plate 24 directly below the frequency converter 2. The heat absorbed by the pressure medium from the frequency converter 2 is then subsequently dissipated via the two fin stacks 144 and the pressure medium heat pipes 146.

[0055] In the fifth embodiment according to Fig. In embodiment 6, air cooling is implemented, which can be used instead of the previously described cooling with a cooling medium. To reduce the number of parts, the connections 154 and the corresponding cooling channel 19 can also be provided on the cooling plate 24 of the fifth embodiment. Compared to the previously described embodiments, the heat pipes 146, 147 are longer here, penetrate the top surface of the cooling plate 24, and are thermally connected to further fin packs 148, 150 on its top surface, e.g., by soldering.

[0056] Preferably, the additional lamination stacks 148 of the pressure medium and the additional lamination stacks 150 of the electric motor M are not thermally connected to each other, since the lamination stacks 150 of the electric motor M may become hotter than the lamination stacks 148 of the pressure medium. For this purpose, four approximately quarter-circle additional lamination stacks 148 for the pressure medium are arranged on the outer area of ​​the cooling plate 24 and four approximately column-shaped smaller lamination stacks 150 for the electric motor M are arranged in the inner area of ​​the top surface of the cooling plate 24.

[0057] The eight additional fin packs 148, 150 create four approximately quarter-circle areas on the top of the cooling plate 24, each containing fin packs. A fan 152 is mounted between each pair of quarter-circle areas to increase cooling performance.

[0058] In the - in Fig. The frequency converter 2 is located in the area shown in the 6 freely displayed section between the lamella packs and the fans 152.

[0059] Fig. Figure 7 shows the largely complete fifth embodiment of the compact unit according to the invention. Fig. Figure 6 shows a perspective longitudinal section. It can be seen that the further fin packs 148, 150, the fans 152, and the frequency converter 2 are covered by a housing 26, the outer diameter of which corresponds approximately to that of the outer wall 48 of the tank T and that of the cooling plate 24. Thus, the entire compact unit is circularly cylindrical. The housing 26 has ventilation slots 164. The electrical cable 6 runs from the frequency converter 2 to the electric motor M through the cooling plate 24.

[0060] The electric motor M is attached to the underside of the cooling plate 24 via a damping element 40.

[0061] The frequency converter has power electronics (not shown in detail) that are positioned directly on the top of the cooling plate 24.

[0062] In the sixth embodiment according to Fig.Figure 8 shows tank T covered by a lid 44 to which the electric motor M is attached. An alternative cooling device is shown. The pressure medium and / or the electric motor M and / or the frequency converter 2 are cooled directly by means of cooling water flowing through a coolant line 167. More precisely, the coolant line 167 is formed by a hose or a pipe that runs through the interior of tank T and / or through or around the electric motor M and / or through a heat sink 166 of the frequency converter 2. The coolant line 167 has a large surface area, e.g., due to a ribbed structure, runs in a spiral shape to achieve a large length, is made of a highly thermally conductive material such as copper or aluminum, and has very thin walls.

[0063] The flow direction of the cooling water in the coolant line 167 is chosen - according to the two arrows - such that it first passes through the component to be cooled the coldest, here the pressure medium, e.g. oil, then the electric motor M and finally the warmest component, the cooling element 166 of the frequency converter 2.

[0064] A compact electro-hydraulic unit has been revealed, in which the hydraulic fluid flowing back into a tank and the electric motor driving a pump are cooled via a common cooling device. According to one variant, a coolant line is provided, and according to a second variant, heat pipes are provided to transport the heat from the hydraulic fluid or the electric motor to a cooling plate. Reference symbol list: 1 pump 2 frequency converters 4 electrical power supply 6 electrical lines 12 Supply line 14 high-pressure side consumer connection 19 Cooling channel 20 Return line Channel 22 24 cooling plate 26 cases 40 damping element 42 Floor 44 lids 46 Inner wall 48 Outer wall 144 slat package 146 Pressure medium heat pipe 147 Motor heatpipe 148 additional slat package 150 additional slat package 152 fans 154 connections 164 ventilation slots 166 heat sinks 167 Coolant line M Motor T Tank

Claims

Electro-hydraulic compact unit with a drive unit comprising an electric motor (M) and a hydrostatic pump (1), wherein pressure medium can be drawn from a tank (T) of the compact unit via the pump (1), characterized by a cooling device extending into an interior of the tank (T), wherein the cooling device comprises a cooling plate (24) by which the tank (T) is sealed and to which the drive unit is attached, and wherein the cooling device comprises at least one pressure medium heat pipe (146) extending from the interior of the tank (T) to the cooling plate (24), and which is thermally attached to or penetrates the cooling plate (24). Compact unit according to claim 1, wherein the cooling device is designed to cool the electric motor (M) and is in a heat-conducting connection with it. Compact unit according to claim 2, wherein the cooling device has a coolant line (167) which is arranged section by section in the interior of the tank (T) and which is in heat-conducting connection with the electric motor (M). Compact unit according to one of the preceding claims, wherein the tank (T) is closed by a lid (44) to which the drive unit is attached. Compact unit according to claim 4, wherein a cooling element (166) is arranged on a side of the lid (44) facing away from the tank (T), to which a frequency converter (2) for the electric motor (M) is attached in a heat-conducting manner, and wherein the cooling element (166) is in a heat-conducting connection with the coolant line (167). Compact unit according to claim 5, wherein the pressure medium, then the electric motor (M) and finally the cooling element (166) can be cooled via the coolant line (167). Compact unit according to one of the preceding claims, wherein at least one lamellar pack (144) is provided in the tank (T) which is heat-conductingly attached to the pressure medium heat pipe (146), and wherein the pressure medium is guided over the lamellar pack (144) inside the tank (T). Compact unit according to claim 7, wherein the pressure medium heat pipe (146) penetrates the cooling plate (24) and is thermally connected to a further fin pack (148) which is arranged on a side of the cooling plate (24) facing away from the tank (T). Compact unit according to one of the preceding claims, wherein the cooling device has a cooling plate (24) by which the tank (T) is sealed and to which the drive unit is attached, and wherein the cooling device has at least one pressure medium heat pipe (146) extending from the interior of the tank (T) to the cooling plate (24), and wherein the cooling device has at least one motor heat pipe (147) extending from the electric motor (M) towards the cooling plate (24), and wherein the heat pipes (146, 147) are heat-conductingly attached to or penetrate the cooling plate (24). Compact unit according to claim 9, wherein the motor heat pipe (147) is inserted into a housing of the electric motor (M) in a heat-conducting manner. Compact unit according to claim 9 or 10, wherein the motor heat pipe (147) penetrates the cooling plate (24) and is thermally connected to a further fin pack (150) which is arranged on a side of the cooling plate (24) facing away from the tank (T). Compact unit according to one of the preceding claims, wherein at least one support surface or at least one support device is arranged adjacent to or on a region of the tank (T) facing away from the cooling plate (24), which defines a support plane of the compact unit to which the heat pipes (146, 147) are arranged approximately perpendicularly. Compact unit according to one of the preceding claims, wherein the electric motor (M) can be electrically supplied via a frequency converter (2) which is attached to the cooling plate (24) on a side facing away from the tank (T) in a heat-conducting manner. Compact unit according to one of the preceding claims, wherein a cooling channel (19; 22) is provided in the cooling plate (24). Compact unit according to claim 14, wherein the cooling channel (19; 22) is manufactured by inserting a tube into an aluminium die-casting mold of the cooling plate (24). Compact unit according to claims 14 and 15, wherein the cooling channel (22) extends along a contact area between the frequency converter (2) and the cooling plate (24) and forms a section of a return line (20) of the pressure medium. Compact unit according to claim 14 with an inlet connection (154) from which a first section of the cooling channel (19) extends in an outer area of ​​the cooling plate (24), and with a second section of the cooling channel (19) connected thereto, which is arranged in an inner area of ​​the cooling plate (24). Compact unit according to one of the preceding claims, wherein the at least one pressure medium heat pipe (146) is attached to or penetrates the cooling plate (24) in the outer region, and wherein the at least one motor heat pipe (147) is attached to or penetrates the cooling plate (24) in the inner region.

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