Transmission for a motor vehicle

Abstract

Transmission for a hybrid or electric vehicle with a cooling unit (13) and a heat source (11), wherein the cooling unit (13) is arranged in an oil chamber of the transmission and adjacent to the heat source (11) and has the following features: a housing (17) made of a thermally conductive material and a thermally conductive structure (15; 16) within the housing (17) which has protrusions such that the thermally conductive structure between the protrusions can be permeated by oil in a flow direction, wherein the heat source (11) has a high-voltage circuit for controlling an electric machine, and wherein the gearbox has a power electronics component which is configured to be surrounded by the oil.

Description

FIELD OF THE INVENTION

[0001] The present invention relates to a transmission for a motor vehicle. TECHNICAL BACKGROUND

[0002] The use of power electronics in vehicles, particularly in hybrid vehicles, is known from the prior art. For example, DE 10 2016 215 188 A1 shows a power electronics system arranged in a cavity of a transmission housing.

[0003] Further prior art is described, for example, in DE 102 96 733 B4, EP 0 951 131 B1, US 2004 / 0 057 208 A1, WO 95 / 35 019 A1, US 3 327 776 A, US 2005 / 0 253 465 A1, DE 10 2018 201 819 A1, DE 198 55 319 A1, DE 199 50 967 A1, US 2004 / 0035 245 A1, DE 101 10 620 A1, US 2009 / 0 114 373 A1, US 2012 / 0 139 096 A1 and DE 10 2016 210 302 A1 shown. SUMMARY OF THE INVENTION

[0004] Against this background, the object of the invention is to provide a transmission with a cooling unit that is compatible with a power electronics component in the transmission.

[0005] This object is achieved according to the invention with the features of patent claim 1.

[0006] Accordingly, it is provided: - a transmission for a hybrid or electric vehicle with a cooling unit and a heat source, wherein the cooling unit is arranged in an oil chamber of the transmission and adjacent to the heat source and comprises the following: a housing made of a thermally conductive material and a thermally conductive structure within the housing, which has elevations so that oil can flow through the thermally conductive structure between the elevations in one flow direction.

[0007] Motor vehicles within the meaning of this patent application are motor-driven land vehicles. This also includes rail vehicles.

[0008] The power electronics serves as a converter for the electrical machine. In particular, the power electronics convert the direct current provided by a battery into alternating current. Furthermore, the power electronics essentially serves to control or regulate the current supplied to the electrical machine. For this purpose, the power electronics comprises a printed circuit board and electronic components electrically connected to it, which are designed to control or regulate the current. For example, the power electronics may comprise a power switch, such as a power transistor. Furthermore, the power electronics may comprise control electronics and / or sensor electronics. The power electronics may comprise a power electronics housing within which the printed circuit board and the electronic components are arranged.

[0009] The electric machine consists of at least a stator and a rotatably mounted rotor and is designed to convert electrical energy into mechanical energy in the form of speed and torque in motor mode, and to convert mechanical energy into electrical energy in the form of current and voltage in generator mode. The electric machine can be used in a hybrid drive in which the power provided by the electric machine is transferred to a transmission output shaft. Of course, the electric machine can also be used for other purposes, such as driving a pump arranged in the transmission. The power electronics can be electrically connected to one or more electric machines.

[0010] A transmission comprises a clutch chamber, in which a clutch rotates, and an oil chamber, which often houses an actuator. The oil chamber is a transmission chamber filled with oil up to a certain level.

[0011] A heat source is an area that is warmer than its surroundings during operation. Components that receive energy, such as electrical circuits, motors, etc., are heat sources because these components heat up due to friction with their surroundings.

[0012] Cooling units transport heat from a heat source to a cooler environment. There are active and passive cooling units. Passive cooling units achieve a cooling effect through a thermally conductive material. Active cooling units achieve a cooling effect through moving parts that circulate media and / or chemical reactions.

[0013] Thermally conductive materials are materials with thermally conductive electrons. Examples include metals. In contrast, non-thermally conductive materials are materials in which heat transfer can occur exclusively through lattice vibrations, so-called phonons.

[0014] An enclosure is a rigid shell that protects sensitive contents or protects the environment from harmful contents.

[0015] The term "oil" is not intended to be limited to mineral oils. Rather, it can also include fully synthetic or semi-synthetic oils, silicone oil, or other oil-like fluids, such as hydraulic fluids or cooling lubricants.

[0016] A wave is a spatially propagating oscillation or a single disturbance. A wave-like structure is a solid whose surface can be described as a wave, for example, by a wave equation. A wave trough is a local minimum of a wave. A wave crest is a local maximum of a wave.

[0017] In physics, an amplitude is the maximum deflection of a sinusoidal alternating quantity. In this patent application, amplitude is defined as the difference, i.e., the vertical distance, between a wave trough and a wave crest.

[0018] Structures through which oil can flow are adapted in terms of dimensions to the viscosity of oil.

[0019] The basic idea of ​​the invention is to arrange a cooling unit through which oil can flow in the oil chamber of a gearbox, next to a heat source.

[0020] The cooling unit comprises a housing made of a thermally conductive material in which a thermally conductive structure is formed.

[0021] Landings are raised structures with a height greater than their width. The base area, which results from the length and width of a landing, is elongated, meaning the length is greater than the width, and can be chosen arbitrarily, for example, a wave-shaped base area.

[0022] Pins are elevations whose height is greater than a width and a length.

[0023] The orientation of width and length in this application can be found in the drawings. The drawings also specify the orientation of width and length on their own, meaning that additional drawn features are not mandatory.

[0024] The height of an elevation is perpendicular to the cutting planes according to Fig. 3 or Fig. 5 oriented.

[0025] The thermally conductive structure includes raised portions between which oil can flow. The raised portions are at least high enough to allow for a substantially laminar flow of oil between the raised portions. The height of the raised portions can be configured to correspond to the internal height of the housing.

[0026] The housing of the thermally conductive structure may be formed in a block of a thermally conductive material.

[0027] This allows the thermal connection in a gearbox to be improved and the installation space of a gearbox to be used optimally.

[0028] In addition, the cooling unit enables the integration of a power electronics component into the transmission without passing water through the transmission.

[0029] Advantageous embodiments and further developments emerge from the further subclaims and from the description with reference to the figures of the drawing.

[0030] According to one aspect of the invention, it can be provided that the elevations of the thermally conductive structure have a plurality of wave-shaped webs between which the oil can flow.

[0031] It is also expedient if the height of a web is between 3.0 mm and 9.0 mm, in particular between 4.0 mm and 5.0 mm and / or the wall thickness of the webs is between 0.5 mm and 1.2 mm.

[0032] For solid structures, i.e. structures without a cavity, the wall thickness corresponds to the width.

[0033] It's also useful if the bridges have several interruptions. This prevents or prevents oil clogging.

[0034] This means that the entirety of the webs has multiple interruptions. This includes, for example, that each of the webs has at least one interruption or that only a selection of the webs has an interruption.

[0035] Alternatively, it is also conceivable that the elevations of the thermally conductive structure have a plurality of pins between which the oil can flow.

[0036] It is also expedient if the pins have a quadrangular cross-section, wherein a length of the cross-section extends in a flow direction of the oil and a width of the cross-section is oriented perpendicular to the length, wherein the width is between 1.0 mm and 1.6 mm, in particular 1.6 mm, and / or the ratio between the width and the length, width / length, is at least 0.5 mm, in particular equal to 0.9 mm, and / or a height, which is oriented perpendicular to the cross-section, of the pins is between 3.0 mm and 10 mm, in particular 6.6 mm and / or a minimum distance between two adjacent pins is between 0.6 mm and 1.2 mm, in particular 0.8 mm.

[0037] According to the invention, the heat source comprises a high-voltage circuit for controlling an electric motor.

[0038] High-voltage circuits are designed for maximum operating voltages between 400 V and 1000 V.

[0039] According to a preferred aspect of the invention, the thermally conductive material of the housing is copper or a copper-containing alloy.

[0040] According to the invention, the transmission has a power electronics component which is designed to be surrounded by the oil.

[0041] It is also useful if the power electronics component has a casing, e.g. made of a potting compound or a molded housing, which seals the power electronics component in an oil-tight manner. TABLE OF CONTENTS OF THE DRAWINGS

[0042] The present invention will be explained in more detail below with reference to the exemplary embodiments shown in the schematic figures of the drawings. In the drawings: Fig. 1 is a schematic sectional view of a cooling unit of a transmission according to an embodiment of the invention; Fig. 2 shows a thermally conductive structure according to an embodiment of the invention; Fig. 3 a detailed view according to Fig. 2; Fig. 4 shows a thermally conductive structure according to an embodiment of the invention; Fig. 5 a detailed view according to Fig. 4.

[0043] The accompanying drawings are intended to provide a further understanding of embodiments of the invention. They illustrate embodiments and, in conjunction with the description, serve to explain principles and concepts of the invention. Other embodiments and many of the noted advantages will be apparent upon review of the drawings. Elements of the drawings are not necessarily shown to scale relative to one another.

[0044] In the figures of the drawings, identical, functionally identical and acting elements, features and components are provided with the same reference symbols, unless otherwise stated. DESCRIPTION OF EMBODIMENTS

[0045] Fig. 1 shows a section of a transmission according to an embodiment of the invention in a sectional view. Accordingly, in Fig. 1, a heat source 11 is arranged next to a cooling unit 13. The cooling unit 13 comprises a housing 17, which is arranged in a copper block 103. The housing 17 has an internal height of 101.

[0046] Fig. Figure 2 shows an overview of a thermally conductive structure 15 arranged inside the housing 17. The thermally conductive structure 15 comprises a plurality of pins 20, which have a square or diamond-shaped cross-section and are arranged in a matrix. The pins 20 form elevations between which oil can flow. The pins 20 have a pin height that is perpendicular to the Fig. 2. Two adjacent pins 20 are spaced 31 apart. Furthermore, the pins have a width 32 and a length 29. Each pin encloses at least a distance 105 from an outer wall of the housing 17.

[0047] Fig. 3 shows an enlarged detailed view according to Fig. 2, which shows the dimensions of the pins.

[0048] Fig. Figure 4 shows an overview of a thermally conductive structure 16 with wave-shaped ridges 19. The ridges 19 form elevations between which oil can flow. The ridges 19 have a wall thickness of 21. Two adjacent ridges 19 enclose a gap 23. Two adjacent troughs of a wave of a ridge 19 are spaced apart by a distance 25. The width of a wave corresponds to the technical dimension of the amplitude 27 of a wave of the ridge 19.

[0049] Fig. 5 shows an enlarged detailed view according to Fig. 4, from which the dimensions of the wave-shaped webs can be seen. Reference symbol 11 Heat source 13 Cooling unit 15 heat-conducting structure 16 heat-conducting structure 17 housings 19 jetty 20-pin 21 wall thickness 23 Distance between two webs 25 Distance between two wave troughs 27 amplitude 29 length 31 Distance between two pins 32 width 101 height 103 copper block 105 Distance to the wall

Claims

[1] Transmission for a hybrid or electric vehicle with a cooling unit (13) and a heat source (11), wherein the cooling unit (13) is arranged in an oil chamber of the transmission and adjacent to the heat source (11) and has the following: a housing (17) made of a thermally conductive material and a thermally conductive structure (15; 16) within the housing (17), which has elevations such that oil can flow through the thermally conductive structure between the elevations in a flow direction, wherein the heat source (11) has a high-voltage circuit for controlling an electrical machine, wherein the transmission has a power electronics component which is designed to be surrounded by the oil. [2] A transmission for a hybrid or electric vehicle according to claim 1, wherein the thermally conductive structure (16) comprises a plurality of wave-shaped webs (16) between which oil can flow. [3] Transmission for a hybrid or electric vehicle according to claim 2, wherein a height of a web (19) is between 3.0 mm and 9.0 mm, in particular between 4.0 mm and 5.0 mm and / or a wall thickness (21) of the webs (19) is between 0.50 mm and 1.2 mm and / or a minimum distance (23) between two webs (19) is between 0.80 mm and 1.5 mm, in particular 1.0 mm and / or the amplitude (27) of a wave of a web is between 1.7 mm and 4.5 mm, in particular between 3.0 mm and 4.0 mm and / or a distance (25) between two adjacent wave troughs is between 4.0 mm and 9.0 mm, in particular between 4.0 mm and 5.0 mm. [4] Transmission for a hybrid or electric vehicle according to claim 2 or 3, wherein the webs (19) have a plurality of interruptions. [5] A transmission for a hybrid or electric vehicle according to claim 1, wherein the thermally conductive structure (15) has a plurality of pins (20) between which the oil can flow. [6] Transmission for a hybrid or electric vehicle according to claim 5, wherein the pins (20) have a quadrangular cross-section, wherein a length (29) of the cross-section extends in a flow direction of the pin and a width (33) of the cross-section is oriented perpendicular to the length, wherein the width (33) is between 1.0 mm and 1.6 mm, in particular 1.6 mm, and / or the ratio between the width (33) and the length (29), i.e. width / length, is at least 0.50, in particular equal to 0.9, and / or a height of the pins is between 3.0 and 10 mm, in particular 6.6 mm and / or a minimum distance (31) between two adjacent pins (20) is between 0.60 mm and 1.2 mm, in particular 0.80 mm. [7] Transmission for a hybrid or electric vehicle according to one of the preceding claims, wherein the thermally conductive material of the housing (17) is copper or a copper-containing alloy. [8] Transmission for a hybrid or electric vehicle according to one of the preceding claims, wherein the power electronics component has a casing which seals the power electronics component in an oil-tight manner.

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