WO2018162083A1

WO2018162083A1 - Electric machine

Info

Publication number: WO2018162083A1
Application number: PCT/EP2017/055735
Authority: WO
Inventors: Hans-Joachim Schröder; Axel Steinshorn
Original assignee: Brose Fahrzeugteile GmbH & Co. Kommanditgesellschaft, Würzburg
Priority date: 2017-03-10
Filing date: 2017-03-10
Publication date: 2018-09-13

Abstract

The invention relates to an electric machine (30) of a motor vehicle (2), in particular a refrigerant compressor (12), comprising a electronic unit compartment (50) and a printed circuit board (56) arranged inside the electronic unit compartment (50), and a first connection (52) that is fixedly maintained inside the electronic unit compartment and is in electric contact with an electric coil (35) of a stator (34). The first connection (52) is in electric contact with a second connection element (80) of the printed circuit board (56) by means of a flexible contact element (86) which is in electric contact with a bridge circuit (70). The invention further relates to a refrigerant compressor (12) of a motor vehicle (2), comprising said electric machine (30).

Description

description

Electric machine

The invention relates to an electrical machine of a motor vehicle, with an electronics compartment, and with a printed circuit board arranged therein. The electric machine is preferably an electric motor and suitably a component of a refrigerant compressor. The invention further relates to a refrigerant compressor with such an electric machine.

Motor vehicles usually have an air conditioner, by means of which a temperature control of an interior of the motor vehicle takes place. When powered by an electric motor vehicles, the required energy storage, such as a high-voltage battery, cooled by an air conditioner. The air conditioning system has a refrigerant circuit, which includes a refrigerant compressor and downstream of a condenser and this fluidly downstream of an evaporator. This is fluidly connected downstream of another heat exchanger, which is in thermal contact with any energy cells of the high-voltage energy storage or with a fan line, which leads into the interior of the motor vehicle. The refrigeration cycle is filled with a refrigerant, such as R134a, R1234yf or CO2.

During operation, a pressure of the refrigerant is increased by means of the refrigerant compressor, which leads to an increase in the temperature of the refrigerant. This is conducted to the condenser, which is in thermal contact with an environment of the motor vehicle. Here, a temperature reduction of the refrigerant, which is in turn relaxed in the downstream evaporator to the original pressure, which is why the temperature of the refrigerant is further reduced. In the downstream heat exchanger, the heat exchanger with the heat exchanger shear thermally contacted component thermal energy transferred to the refrigerant, resulting in a cooling of the component and a heating of the refrigerant. The heated refrigerant is again supplied to the refrigerant compressor for closing the refrigerant cycle.

The refrigerant compressor is usually driven by a belt drive from an internal combustion engine of the motor vehicle and has a compressor head, which is for example a scroll compressor head. If the air conditioning system is a component of a motor vehicle that does not include an internal combustion engine, the refrigerant compressor has an electric motor, by means of which the compressor head is driven. Here, the rotational speed of the drive and thus the cooling capacity of the air conditioner is adjusted based on a temperature setting of a user of the motor vehicle or a realized temperature of the high-voltage battery.

The electric motor is usually designed brushless, wherein the individual electric coils are energized by means of a bridge circuit of a printed circuit board. In this case, electric coils of the electric motor are electrically contacted, for example by means of blade and fork contacts, with conductor tracks of the conductor tracks, which in turn are electrically contacted with the bridge circuit. This has semiconductor switches which are actuated by means of a PWM control. At high power requirements and comparatively low speeds, the resulting required electrical currents are comparatively large. As a result, the conductor tracks of the circuit board must be made comparatively robust.

The printed circuit board is usually arranged within an electronics compartment of a housing of the refrigerant compressor and fixedly connected to the housing, for example by means of clips or screws. If different pressures prevail within the housing, namely a low pressure on the stator side and atmospheric pressure on the electronics side, the housing wall can bulge axially into the electronics compartment. If the circuit board would be attached to this housing wall (housing intermediate wall), this could thus be damaged, and / or an electrical Contact between the circuit board and the electric coils are interrupted. Thus, this housing wall can not be used for mounting, although this one would be most suitable for cooling the circuit board.

The invention has for its object to provide a particularly suitable electrical machine of a motor vehicle and a particularly suitable refrigerant compressor of a motor vehicle with an electric machine, in particular a reliability and preferably manufacturing costs are reduced.

With regard to the electric machine, this object is achieved by the features of claim 1 and in terms of the Kä Item ittel compiler by the features of claim 14 according to the invention. Advantageous developments and refinements are the subject of the respective subclaims.

The electric machine is a component of a motor vehicle and preferably a generator or an electric motor. For example, the electric motor is used to drive the motor vehicle, which is thus in particular an electric vehicle or a hybrid vehicle. However, the electric machine is preferably a component of an auxiliary unit of the motor vehicle, for example a variable drive, such as a steering motor of a so-called power steering, an electric window lifter or an electric seat adjustment. Suitably, the electric machine is electrically contacted in the assembled state with a vehicle electrical system of the motor vehicle and is energized by means of it. In particular, the electric machine is suitable for this purpose. For example, the vehicle electrical system of the motor vehicle is a low-voltage on-board electrical system and carries, for example, an electrical voltage of 12 volts, 24 volts or 48 volts. Alternatively, the voltage applied during operation on the electric machine or which has the electrical system of the motor vehicle, 288 volts, 450 volts, 650 volts or 830 volts.

Particularly preferably, the electric machine is a component of a refrigerant compressor, which is thus an electromotive refrigerant compressor. The electromotive refrigerant compressor is in particular a component of a refrigeration system. temittelkreislaufs of the motor vehicle, by means of which, for example, a temperature of the interior of the motor vehicle and / or cooling of an energy storage of the motor vehicle takes place during operation. In particular, the electromotive refrigerant compressor comprises a compressor head, for example a scroll compressor. Particularly preferably, a refrigerant is compressed by means of the electromotive refrigerant compressor, for example a chemical refrigerant, such as R134a or R1234yf. Alternatively, CO2 is used as the refrigerant.

The electric machine is preferably designed brushless and in particular a brushless electric motor, such as a brushless DC motor (BLDC). The electrical machine thus has at least one electrical coil, by means of which at least partially an electromagnet is formed. The electrical coil (winding, motor or phase winding, rotating field winding) is a component of a stator of the electric machine. Preferably, the stator comprises a number of such electrical coils, for example, two, three, six, twelve, wherein the electrical coils are preferably connected to electrical phases of the electric machine, for which they are electrically contacted with each other in a parallel or series connection. The electrical phases themselves are in particular electrically connected to one another in a triangular or star connection. Preferably, the electric machine is designed in three-phase, six-phase or twelve-phase.

The energization of the electrical coil or the tap of the voltage applied to the electrical coil electrical voltage by means of a printed circuit board, which is in particular a part of an electronic system. Here, the electrical coil is electrically contacted with a bridge circuit of the circuit board. The printed circuit board preferably has a carrier, which is made in particular of a woven material, for example a glass fiber fabric, or paper, which are preferably surrounded by a matrix which is, for example, epoxide or at least comprises it. In particular, conductor tracks are connected to and / or embedded in the carrier. The interconnects themselves are made for example of a copper. The bridge circuit preferably has four, six or twelve bridge branches and is thus a B4, B6 or B12 circuit. Two bridge branches are each associated with one of the electrical phases of the electrical machine, and / or the bridge circuit is preferably guided against a DC side, which is in particular electrically contacted with the on-board network. In particular, each of the bridge branches has a semiconductor component, in particular a semiconductor switch, and preferably a power semiconductor switch. In particular, a power electronics is provided with the circuit board or the circuit board is part of the power electronics.

The electric machine has an electronics compartment, which is for example a part of a housing of the electrical machine. In particular, the housing / electronics compartment is made of a metal, for example aluminum or an aluminum alloy. Preferably, the housing is created as a die-cast part. Within the electronics compartment, the circuit board is arranged, wherein the stator, and in particular the electrical coil, is located outside the electronics compartment. In particular, the circuit board is arranged parallel to the housing wall. The electronics compartment itself is preferably airtight and pressure-tight in the assembled state, which is why damage to the printed circuit board is essentially ruled out.

The electric machine has a first terminal that is electrically contacted with the electrical coil of the stator. For example, the first terminal is integral with the electrical coil. In this case, the first connection is preferably formed by means of one end of the electrical coil. Alternatively, the first terminal is a separate component, which is electrically contacted with the electrical coil, in particular directly, and preferably mechanically connected to this, for example, soldered or welded. Particularly preferably, the first connection is contacted directly with the electrical coil. The first connection thus preferably represents a phase connection, that is to say a connection to one of the electrical phases of the stator, provided that the electrical machine has a plurality of phases. The first connection is inside the electrical nikfachs kept stationary. For example, the first Anschiuss is attached to a wall of the electronics compartment. By means of the first connection thus takes place electrical contacting through a wall of the electronics compartment, wherein at least a portion of the first terminal is located fixed to a defined, specific position within the electronics compartment. The first Anschiuss particular rigid is attached to a housing wall of the electronics compartment.

The first Anschiuss is electrically contacted by means of a pliable contact element with a second Anschiuss, wherein the second Anschiuss is a part of the circuit board. The second Anschiuss itself is electrically contacted with the bridge circuit of the circuit board, for example by means of a conductor track. The second Anschiuss is preferably rigidly connected to other components of the circuit board, in particular on the support of the circuit board. The pliable contact element is designed to be flexible, which is why the electrical connection between the first and second Anschiuss is substantially flexible. Due to the pliable contact element a length and / or train compensation between the first Anschiuss and the second Anschiuss is possible. The pliable contact element is particularly suitable, preferably designed to carry electrical currents of more than 100 amps, 150 amps or 200 amps, the current carrying capacity, for example, less than 1, 000 amps, 900 amps or 800 amps.

The first and second Anschiuss are preferably rigidly connected to other components of the electrical machine, in particular at one

Housing wall of the electronics compartment or on the circuit board. Due to the pliable contact element a tolerance compensation is created during movement of these two components to each other during operation, which is why even in the worst case always an electrical connection between the two terminals is ensured, for example, if one of the two components due to pressure or heat input compared to the each other components is deformed. Also, a tolerance compensation is present during assembly, which is why the individual components can be manufactured with a comparatively large manufacturing tolerance, which reduces manufacturing costs. It is also possible light, to position the circuit board within the electronics compartment, in which a comparatively efficient cooling prevails, why the circuit board, in particular the bridge circuit, can be made with electrical or electronic components having a comparatively low maximum operating temperature.

The stator is preferably arranged within the housing and designed, for example, substantially hollow cylindrical. The electronics compartment is preferably located on the front side of the hollow cylindrical stator. In particular, the stator circumferentially surrounds a rotor, which is also positioned within the housing and rotatably mounted about a rotation axis. The rotor itself has, for example, a number of permanent magnets. When operating the electric machine as an electric motor, in particular the electrical coil, preferably the number of electrical coils, is energized by means of the printed circuit board, so that a rotating magnetic field is provided. By means of a magnetic interaction between the permanent magnet (s) of the rotor and the electromagnet (s) of the stator (s) formed by the electrical coil (s), the rotor is set in rotation about the axis of rotation. For example, a compressor head is connected to the rotor if the electric machine is part of a refrigerant compressor. Preferably, the compressor head is located on the opposite side of the electronics compartment of the stator.

Preferably, the first Anschiuss is guided by a housing wall. In other words, one end of the first terminal is within the electronics compartment, and another end of the first terminal is located outside the electronics compartment, these two areas being separated by means of the housing wall. In this case, the electric coil is preferably connected to the end of the first connection located outside the electronics compartment. Due to the passage through the housing wall of the first Anschiuss is held stable, and an electrical contact is simplified. Conveniently, the first Anschiuss positive and / or non-positively within a recess of the housing wall. In particular, between the first Anschiuss and the housing wall a pressure-tight seal available. As a result, it is possible to design the electronics compartment pressure-tight, which is why any damage or contamination of the circuit board is prevented. In particular, the first connection extends in the axial direction, and the housing wall is arranged substantially perpendicular to the axial direction, that is to say parallel to the direction of rotation. Suitably, the pliable contact element is at least partially by means of a (first) heat-conducting on the housing wall. In this way, heat dissipation from the pliable contact element to the housing wall is made possible. In addition, an electrical insulation with respect to the housing wall is created by means of the (first) Wärmeleitpads.

Conveniently, the pliable contact element has a rigid first contact portion and a rigid second contact portion. Between the first and second contact portion, a flexible third contact portion is arranged. In particular, the first and second contact portions are connected to the third contact portion. Consequently, by means of the third contact portion, the bending slackness of the pliable contact element is provided. The first contact portion is mechanically connected to the first terminal and the second contact portion is mechanically connected to the second terminal. In particular, the first contact portion is attached to the first terminal and the second contact portion is attached to the second terminal. Consequently, the first and second contact portion are also held rigidly and the Biegeschlaffheit is provided only by means of the third contact portion, by means of which therefore a tolerance compensation can take place. Thus, on the one hand assembly is simplified, since the respectively defined first and second contact portions are relatively easy to assemble. On the other hand, a production of the pliable contact element is simplified, since by means of the first and second contact portion in each case a breakpoint for any tools is provided.

In particular, the first and second contact portion and the third contact portion are made of a metal, in particular of the same material, which reduces any electrical resistances. Conveniently, the first Contact portion made of the same material as the first terminal and / or the second contact portion made of the same material as the second terminal, which also reduces electrical resistance and thus increases efficiency. Conveniently, the pliable contact element is made entirely of copper or a copper alloy. However, at least the first contact section, the second contact section or the third contact section is made of a copper, ie copper or a copper alloy. In an alternative to this, the pliable contact element is at least partially made of a brass, wherein, for example, the first contact portion, the second contact portion and / or the third contact portion made of brass.

For example, the third contact section is created by means of strands. Particularly preferably, the third contact portion is made of a braid. In this way, on the one hand, the required flexibility is provided, wherein due to the intertwined individual strands or the like a mechanical stability is present. Also, an unintentional separation of the individual strands is prevented from each other, which could otherwise lead to a possible arc formation. For example, the individual, the braid forming strands are interwoven or twisted. Due to the configuration as a braid in this case comparatively small inductances are present, which is why an efficiency of the electric machine is increased. In particular, the braid is elastically or plastically deformable, which simplifies assembly and leads to a comparatively safe operation, wherein even with shock or deformation of the electronics compartment always the electrical contact between the first and the second terminal is present. For example, the braid is a copper braid and thus made of copper or a copper alloy, resulting in a comparatively low electrical resistance.

In particular, the first contact portion has a socket or eyelet. Alternatively, the second contact portion has a socket or eyelet. Particularly preferably, both the first and the second contact section comprise the Bush or eyelet. Here, the socket or eyelet is the attachment of the respective contact portion to the associated terminal. The bush or eyelet is provided here a recess or has a recess. At the recess preferably engages a fastener, by means of which the respective contact portion is mechanically held at the respective associated terminal. Alternatively or particularly preferably in combination with this, the first contact section and the first connection are pressed together. For example, the first contact portion and / or the first terminal is plastically deformed by means of force application, which is why the first contact portion and the first terminal both electrically and mechanically contacted and held together. In particular, in this case, the bush or eyelet is deformed. Consequently, a press fit is created between the respective contact section and the associated connection, in particular between the respective socket. In other words, it is created between the first contact portion and the first terminal. As a result, no further fastening means are required, and also the electrical connection between the first contact portion and the first terminal is created by means of the pressing. Consequently, no additional manufacturing steps are required. All this leads to reduced production costs.

Alternatively or particularly preferably in combination with this, the second contact section and the second connection are screwed together. In particular, this is done by means of a screw or a bolt which is guided through the bush or eyelet. In this case, a nut is preferably arranged on the free end of the screw or the bolt, by means of which a frictional connection between the second contact section and the second connection is created. For example, the head of the screw is supported on a wall of the housing, in particular on the housing wall, through which the first terminal is guided, if this is the case. In particular, the screw is arranged substantially axially, which is why the head is supported in the axial direction on the housing wall. Between the screw head and the housing wall is preferably an electrical insulation, such as a plastic, so that an electrical short circuit between different screws is prevented, provided that the electric machine has a number of such second contact portions and second terminals. For production, the first connection within the electronics compartment is particularly preferably first held stationary, this being done, for example, directly during production of the electronics compartment. Following this, in particular the pliable contact element is inserted into the electronics compartment and the first contact section is pressed with the first connection. Following this, the printed circuit board is inserted into the electronics compartment and the second connection is screwed to the second contact section. In particular, the screw is already inserted into the socket or eyelet of the second contact portion when the pliable contact element is inserted into the electronics compartment. In a further alternative, the first contact section is screwed to the first terminal and / or the second contact section is pressed to the second terminal. In other words, a pressfit is created between the second contact section and the second connection.

In summary, the mechanical connection and electrical contacting is preferably carried out by means of screws which are guided through the bushing or eyelet. In particular, the second terminal is located on the opposite side of the printed circuit board from the second contact section, and the nut is in direct mechanical contact with the second terminal. The screw head, on the other hand, is on the side of the circuit board on which the second contact section is located, and the screw head is in direct mechanical contact with the second contact section. The third contact section is preferably located between the printed circuit board and the housing wall, to which the first terminal is in particular connected. The screw or the bolt and / or the associated nut is made for example of a steel, which is why a mechanical connection is relatively stable. In an alternative, the nut is arranged on the side of the third contact section, and the screw head or bolt head is located on the opposite side. the side of the printed circuit board and is suitably in direct mechanical contact with the second terminal.

For example, the respective head of the screw or of the bolt is connected via a heat conducting pad / the (first) heat conducting pad to the housing wall and / or is applied via this to the housing wall, wherein the (first)

Thermal pad, for example, also serves the electrical insulation. Due to the Wärmeleitpads is a heat dissipation from the circuit board to the

Housing wall allows, in particular, is in thermal contact with a coolant, such as air or the refrigerant, if the electric machine is part of a refrigerant compressor. Here is the

Housing wall preferably made of an aluminum material.

Preferably, the second contact portion has a hollow cylindrical projection, which is suitably arranged at least partially within an opening of the printed circuit board. In particular, a clearance fit between the circuit board and the hollow cylindrical projection is created. Due to the hollow cylindrical projection of the second contact portion is at least partially stabilized with respect to the circuit board, so that any fastening element, such as a screw, only relatively small forces must apply for holding the second contact portion at the second terminal. Also, an assembly is simplified. In particular, the hollow cylindrical projection is realized by means of the socket. For example, the opening of the printed circuit board is at least partially covered on the edge side by means of the second connection, which is why the hollow cylindrical projection can only be inserted from one side into the opening. Also, a stop for the hollow cylindrical projection is created in this way. As a result, the second contact portion is further stabilized.

For example, the first and the second terminal at different distances to the axis of rotation of the electric machine. In this case, the first connection is preferably arranged closer to the axis of rotation than the second connection. As a result, it is possible to use a comparatively large printed circuit board, in particular if the printed circuit board has a number of second Has conclusions. Thus, a relatively high heating of the circuit board can be avoided in only a single area. In particular, the bridge circuit is arranged distributed on the circuit board, which makes uniform a heat load on the circuit board, which is why comparatively inexpensive electrical or electronic components of the circuit board can be used. In summary, it is possible that at least parts of the bridge circuit have a comparatively large distance from the axis of rotation. In particular, the circuit board is designed substantially rotationally symmetrical, so that different components of the individual bridge arms of the bridge circuit have a comparatively large distance from each other, if the bridge circuit has a plurality of such bridge arms. This leads to a comparatively uniform heat load on the printed circuit board, which is why on the one hand a punctual comparatively strong heat load is avoided. On the other hand, a stress due to differential expansion due to the varying temperature is excluded. Due to the smaller distance of the first terminal to the axis of rotation manufacturing of the electric motor is simplified. Also, a comparatively small housing can be used for the electric machine, so that a comparatively compact electric machine is provided.

The bridge circuit preferably has a power semiconductor switch. In particular, each bridge branch has two power semiconductor switches which are connected in parallel with each other, which reduces the electric current to be switched with each of the power semiconductor switches. For example, the power semiconductor switch is provided with a heat conducting pad, which preferably overlaps the respective power semiconductor switch on all sides and thus also bears against the corresponding sections of the printed circuit board. In the assembled state, the heat-conducting pads or the heat-conducting pad are preferably on the housing wall, which is why a comparatively efficient heat conduction from the power semiconductor switch is made to the housing wall, and therefore the operational heat of the power semiconductor switch is introduced into the housing wall. Preferably, the cooling of the power semiconductor switch is also carried out over relatively large-area copper traces of the circuit board. The power semiconductor switches are, for example, IGBTs or field effect transistors (FET). Particularly preferably, the power semiconductor switches are DirectFETs. In other words, the bridge circuit comprises DirectFETs. The comparatively flat-building DirectFETs are arranged in particular on the side of the printed circuit board facing the housing wall, if this is present. In particular, the power semiconductor switches, in particular the DirectFETs, are spaced from a central region of the printed circuit board and are preferably arranged in an edge region. In particular, the power semiconductor switches are located in an outer half of the printed circuit board, which reduces heat load. In particular, the DirectFETs are covered with (second) Wärmeleitpads. For example, in each case two, three or four DirectFETs are each assigned a (second) heat-conducting pad. By means of the

Wärmeleitpads the DirectFETs are preferably contacted with a housing wall thermal, in particular with the housing wall through which the first connection is possibly out. In this way, a cooling of the DirectFETs is improved.

In particular, the circuit board is arranged parallel to a plane and stored floating to just this level. Consequently, the circuit board is floating within the electronics compartment. Consequently, in conjunction with the pliable contact element, the printed circuit board can be moved perpendicular to the plane at least in a certain area, so that damage to the printed circuit board due to vibration or deformation of the electronics compartment can be ruled out. Also, it is thus possible to manufacture the printed circuit board and the electronics compartment made of materials with different coefficients of thermal expansion, with no mechanical stresses between the printed circuit board and the electronics compartment, in particular the housing wall of the electronics compartment, occur during heating.

If the electric machine is a component of a refrigerant compressor, in particular two areas with different static pressures are separated from each other by means of the housing wall. For example, within the Elektronikfachs an atmospheric pressure, which is preferably smaller than the pressure on the opposite side of the housing wall. In particular, there is a low pressure side on this side, this pressure being greater than the pressure inside the electronics compartment. On the low pressure side, the stator is suitably positioned. Due to the floating storage, the

Housing wall are made comparatively narrow, and the housing wall may bulge axially into the electronics compartment due to the pressure difference. Due to the floating bearing no mechanical stress is introduced into the circuit board despite the deformation of the housing wall. Consequently, the circuit board can be positioned comparatively close to the housing wall, which is why a heat dissipation to the housing wall and in particular to the low pressure side can be made comparatively efficient. Preferably, the plane is perpendicular to the axis of rotation. In other words, the circuit board is arranged perpendicular to the axis of rotation, and the housing wall is located frontally of the stator. As a result, a comparatively large heat dissipation of the printed circuit board and other components of the electronics compartment is made possible on the low pressure side over the housing wall.

Conveniently, the electronics compartment has a perpendicular to the plane extending dome, which is in particular connected to the housing wall, in particular integrally formed. The dome itself protrudes in particular through a recess in the printed circuit board. By means of the dome and the recess, the circuit board is guided perpendicular to the plane, in particular parallel to the axis of rotation. In other words, the printed circuit board can be displaced at least a certain amount along the dome. Preferably, the floating bearing is limited by stops or due to the length of the pliable contact element. Also, expansion of the circuit board in the plane is prevented only in the region of the recess. Otherwise, expansion is not hindered and mechanical stresses can be relieved.

In particular, a clearance is created between the dome and the circuit board by means of the recess. As a result, the circuit board is secured against in-plane displacement, thereby damaging any edges the circuit board can be excluded due to an unwanted contact with further limitations of the electronics compartment. Suitably, the recess is located in an inner region of the printed circuit board, and is in particular in the center of gravity, or has at least a comparatively small distance from the center of gravity, for example less than 10% of the extent of the printed circuit board. As a result, any expansion of the circuit board due to heat input with respect to the recess is substantially uniform and any imbalances are avoided.

Preferably, the circuit board is spaced by means of a spacer element from a perpendicular to the plane extending wall of the electronics compartment. In other words, the wall is arranged parallel to the circuit board, and the circuit board is spaced by means of the spacer to the wall. In particular, the distance is between 0.1 mm and 2 mm. The wall is especially the

Housing wall through which the first connection is made. As a result, mechanical deformation of the wall is not transmitted directly to the circuit board, which increases the robustness of the electrical machine. For example, the spacer is attached to the wall and the circuit board. Suitably, the spacer is attached either to the circuit board or to the wall. In particular, the spacer element is only attached to the wall, and the circuit board rests only on a free end of the spacer element. In other words, the circuit board is not attached to the spacer, but only placed on this. Conveniently, the electric machine comprises a number of such spacers, for example between two and fifteen, between four and ten and in particular six or seven. The spacer element is designed, for example, cylindrical and

suitably oriented perpendicular to the plane. For example, the spacer element is made of an electrically non-conductive material, such as plastic. In particular, the spacer element is made of a

Made ceramic material, which is why a comparatively stable electric machine is provided. In summary, spacers (axial pins, spacers) are provided for the realization of the floating bearing, which extend in particular in the axial direction. The spacer elements are arranged at predetermined positions and define a distance, for example, between 0.1 mm to 2 mm between the circuit board and the housing wall, which is always maintained. The spacer element is in particular in the form of a preferably cylindrical pin, which is made for example of a ceramic material. In particular, in each case one of the pins is positioned in the center of a group of, for example, four power semiconductor switches, in particular DirectFETs.

The spacer elements are in particular spaced from a central region of the printed circuit board and preferably arranged along a circular path, the center of which is for example the recess of the printed circuit board, if this is present. For example, the electronics compartment has a cover, which is arranged in particular parallel to the printed circuit board. In particular, a further element is arranged between the printed circuit board and the electronic compartment cover, by means of which the printed circuit board is fixed in the axial direction. Consequently, by means of the spacer elements and the further element axial forces targeted, especially punctually and / or locally introduced into the circuit board, which is why the circuit board is held within the electronics compartment alone by forces perpendicular to the circuit board reliable, while forces in the plane or force components within the plane , which could lead to mechanical stresses in the circuit board, avoided or at least significantly reduced.

The refrigerant compressor is a component of a motor vehicle and includes an electric machine as a drive. The refrigerant compressor is thus an electromotive refrigerant compressor (eKMV). The electric machine is, for example, a brushless DC motor (BLDC). Preferably, the refrigerant compressor, in particular the electric machine, electrically contacted with an electrical system of the motor vehicle contacted and / or operated with an electrical voltage of a few volts up to 1000V / operable, in particular with an electrical voltage of 12V, 24V, 48V, 288V, 450V, 650V or 830V. By means of the refrigerant compressor, a refrigerant is compressed during operation. The cold agent is for example a chemical refrigerant, such as R134a or R1234yf. Alternatively, the refrigerant is CO2. Preferably, the element is designed in such a way that the respective refrigerant can be compressed by means of which the pressure increases between 5 bar and 20 bar, for example. The refrigerant compressor is in particular a component of a refrigeration cycle which, for example, serves to air-conditioning an interior space or to cool an energy store of the motor vehicle, such as a high-voltage battery. For example, the electromotive refrigerant compressor is signal technically coupled to a bus system, in particular a LIN or CAN bus.

The electric machine has a stator with an electrical coil, in particular a number of electrical coils, which are combined into a number of electrical phases. Furthermore, the electric machine comprises an electronics compartment and a printed circuit board arranged therein. Within the electronics compartment, a first terminal is fixedly held, which is electrically contacted with the electric coil, and which is konta kitten by means of a pliable contact element electrically with a second terminal of the circuit board. The second terminal is electrically contacted with a bridge circuit of the printed circuit board. In particular, the bridge circuit is the energization of the electric coil, or the electrical phase.

The bridge circuit preferably has a number of bridge branches corresponding to the number of electrical coils / phases. In particular, the number of bridge branches is equal to the number of electrical phases and / or an integer multiple of the number of electrical coils. Each bridge branch is assigned, for example, a DC link capacity. Each bridge branch in particular has two series-connected semiconductor switches, in particular power semiconductor switches. The power semiconductor switches are provided and arranged to switch an electric current with a current of at least A, 2A, 5A or 10A. The power semiconductor switches are preferably IGBTs or field effect transistors (FETs), in particular directFETs. In particular, two power semiconductor switches are connected in parallel to one another, so that each bridge branch has four such power semiconductor switches includes. In this way, an electric current carried by the respective power semiconductor switch is reduced, which reduces manufacturing costs.

The refrigerant compressor is suitably a component of a refrigerant circuit with an (air) condenser, as well as with an evaporator, and with the refrigerant compressor. The condenser is fluidly connected between the refrigerant compressor and the evaporator. Preferably, the refrigerant circuit comprises a further heat exchanger, which is connected between the evaporator and the refrigerant compressor, and which is preferably thermally contacted with another component of the motor vehicle, such as a blower line of an air conditioner or an energy storage, such as a high-voltage energy storage. The refrigerant circuit is filled in particular with a refrigerant, for example a chemical refrigerant, such as R134a, R1234yf, or with CO2.

By means of the refrigerant compressor, a pressure of the refrigerant is increased during operation, which is subsequently passed to the condenser, which is preferably in thermal contact with an environment of the motor vehicle. Preferably, by means of the capacitor, a temperature equalization of the refrigerant to the ambient temperature or at least a decrease in the temperature of the refrigerant. With the downstream evaporator, the refrigerant is expanded, which is why the temperature of the refrigerant is further reduced. In the downstream further heat exchanger is transferred from the thermally contacted with the other heat exchanger component thermal energy to the refrigerant, resulting in a cooling of the component and heating of the refrigerant. The heated refrigerant is preferably supplied again to the refrigerant compressor for closing the refrigerant circuit.

The invention will be explained in more detail with reference to a drawing. Show:

1 shows schematically a motor vehicle with a refrigerant compressor,

2 in a sectional view schematically simplifies the refrigerant compressor, 3 is a plan view of a circuit board,

4 shows the printed circuit board in a bottom view,

5 is a perspective view of a slippery contact element,

6 arranged in an electronics compartment pliable contact elements,

7/8, the assembly of the circuit board by means of one of the pliable contact elements,

Fig. 9, the circuit board with mounted limp contact elements of FIG. 4, and

10 is a perspective view of one of the attached to a second terminal pliable contact elements.

Corresponding parts are provided in all figures with the same reference numerals.

In Fig. 1 is a simplified simplified representation of a motor vehicle 2 with two front wheels 4 and two rear wheels 6. At least two of the wheels 4, 6 are driven by means of a main drive not shown in detail, for example an internal combustion engine, an electric motor or a combination thereof. The motor vehicle 2 comprises a refrigerant circuit 8, which is part of an air conditioning system. The refrigerant circuit 8 is filled with a refrigerant 10, for example CO2, R1234yf or R134a. By means of a (electromotive) refrigerant compressor (eKMV) 12, the refrigerant 10 is compressed and fed to a fluid-technically downstream capacitor 14, which is acted upon by ambient air, which leads to a decrease in temperature of the refrigerant 10. The pressure and thus the temperature of the refrigerant 10 is lowered by means of a downstream evaporator 16, which comprises a further heat exchanger not shown in detail, which is thermally coupled to a fan line of the air conditioner. The fan line promotes cooled air in an interior of the motor vehicle 2 as a function of a user setting.

The electromotive refrigerant compressor 12 is signal-coupled by means of a bus system 18, which is a CAN bus system or a Lin bus system, to a motor vehicle controller 20, such as an on-board computer. By means of a (electrical) electrical system 22, which carries the respective electrical voltage, for example, 48V, and is powered by a battery 24, the electromotive refrigerant compressor 12 is energized. The onboard network 22 further includes a securing device 26, by means of which an electric current flow between the battery 24 and the refrigerant compressor 12 can be prevented. For this purpose, the securing device 26, for example, a load and / or circuit breaker. The safety device 26 is connected by means of the bus system 18 signal technology with the motor vehicle control 20 so that actuated by means of the motor vehicle control 20 of the load or circuit breaker and thus the electric current flow can be prevented.

2 shows the electromotive refrigerant compressor 12 in a sectional view along an axis of rotation 28 of an electric motor 30 of the refrigerant compressor 12. The electric motor 30 is a brushless DC motor (BLDC) and has a cylindrical rotor 32 which is circumferentially surrounded by a hollow cylindrical stator 34. The stator 34 has a number of electrical coils 35, in the example shown, twelve electric coils 35. The rotor 32 includes a number of permanent magnets and is rotatably mounted about the axis of rotation 28 by means of a shaft 36. On the shaft 36, a compressor head 38 is connected non-rotatably on the free end, for example a scroll compressor. The stator 34 is energized by means of an electronics 40 of the electric motor 30, which is connected to the bus system 18 and the vehicle electrical system 22.

The stator 34, the rotor 32, the compressor head 38 and the electronics 40 are arranged in a housing 42 made of an aluminum die cast, which has a substantially hollow cylindrical shape and is concentric with the axis of rotation 28. The housing 42 comprises an inlet 44 via which the refrigerant 10 enters the housing 42 and is sucked along the rotor 32 / stator 34 to the compressor head 38, by means of which an increase in pressure takes place. The compressed by means of the compressor head 38 refrigerant 10 is conveyed by means of a drain 46 from the housing 34. The housing 42 comprises a housing wall 48, by means of which an electronics compartment 50 is delimited and separated from the portion of the housing 42 through which the refrigerant 10 flows. In the flowed through by the refrigerant 10 part of the housing 42, the stator 34 and within the electronics compartment 50, the electronics 40 is arranged. Through the housing wall 48, six first terminals 52 are guided, of which only one is shown, and which is essentially a made of copper pin, which is arranged parallel to the direction of rotation 28. In other words, one end of each first connection 52 is located within the portion of the housing 42 through which the refrigerant flows. This end of the respective first connection 52 is electrically contacted with one of the electrical coils 35 of the stator. The remaining end of each first terminal 52 is disposed inside the electronics compartment 50. The first terminals 52 are attached to the housing wall 48, wherein the area between the first terminals 52 and the housing wall 48 is designed pressure-tight. Also, in this case, an electrical insulation of the first terminals 52 of the housing wall 48. Due to the embedding within the housing wall 48, the first terminals 52 are held stationary.

On the housing wall 48 in the axial direction, ie parallel to the axis of rotation 28, opposite side, the electronics compartment 50 comprises a housing made of a metal housing cover 54 which is releasably secured by screws to other components of the electronics compartment 50, and which closes an opening of the electronics compartment 50 , The electronics 40 has a printed circuit board 56 and a further printed circuit board 58, which are arranged one above the other in the axial direction. The printed circuit board 56 is arranged in a plane parallel to the housing wall 48 and parallel to the housing cover 54 and parallel to the other printed circuit board 56. The printed circuit board 56 is positioned between the further printed circuit board 58 and the housing wall 48. In summary, the arrangement of the housing cover 54, the printed circuit board 56, the further printed circuit board 58 and the housing wall 48 is a sandwich construction.

The housing wall 48 has a dome 60 which is parallel to the axis of rotation 28 and through which the axis of rotation 28 extends. The cylindrical dome 60, the is integral with other components of the housing wall 48 is formed to form a clearance within a recess 62 of the circuit board 56. The dome 60 thus protrudes through the circuit board 56, and the dome 60 is spaced from the other circuit board 58. On the housing wall 48 spacer elements 64 are further connected, one of which is shown in Fig. 2 by way of example. The spacers 64 are cylindrical pins, which consist of a

Ceramic material are created, and which are arranged parallel to the rotation axis 28 and on a circular path around the dome 60 around. The circuit board 56 rests on the facing free ends 66 of the spacers 64, and is not attached to these. By means of the spacer elements 64, the circuit board 56 is spaced from the housing wall 48, wherein the distance is about 1 mm. On the opposite side of the spacer elements 64 of the printed circuit board 56 are arranged in a variant of the invention unspecified further holding elements which press the circuit board 56 in this area against the free end 66. As a result, axial forces are introduced in the assembly of the circuit board 56 in the electronics compartment 50 quasi just selectively directly into the housing wall 48.

In summary, the circuit board 56 is held in the radial direction, ie perpendicular to the axis of rotation 28 only by means of the dome 60, wherein a displacement of the circuit board 56 is parallel to the rotation axis 58 by a certain amount possible. Thus, the circuit board 56 is floating. This mounting of the printed circuit board 56 prevents mechanical stresses due to expected deformation of the housing wall 48, in particular deformations parallel to the axis of rotation 28 (axial direction) due to the pressure difference between the low pressure region within the region of the housing 42, in which the stator 34 is arranged, on the one hand and the Atmospheric pressure within the electronics compartment 50 on the other hand.

The circuit board 56 is shown in perspective in FIG. 3 in a plan view and in FIG. 4 in a bottom view from the side of the housing wall 48. The printed circuit board 56 has a bridge circuit 70 with six bridge branches 72 connected in parallel to one another. Parallel to the bridge branches 72 a buffer capacity 74 is connected in each case with three electrolytic capacitors 76. The two Electrodes of each buffer capacitor 74 are routed against a positive pole and a negative pole, which form substantially a DC side of the bridge circuit 70. The DC side is electrically connected via the on-board network 22 to the battery 24.

Each of the bridge branches 72 has four semiconductor switches 78. The semiconductor switches 78 are DirectFETs, ie field-effect transistors. Two of the semiconductor switches 78 are connected in parallel to each other. The two pairs formed in this way are electrically connected in series with each other, wherein the two terminals of this pair are electrically guided against the positive pole and the negative pole, respectively. Due to the parallel connection of the two semiconductor switches 78 of each pair, an electrical current to be switched by means of the respective semiconductor switch 78 is reduced by substantially half.

The printed circuit board 58 also has six second terminals 80 which are located on the side of the printed circuit board 56 facing away from the housing wall 48. Each of the bridge branches 72 is associated with one of the second terminals 80, for which they are electrically contacted by means of a conductor track, not shown. The respective conductor track is in this case electrically contacted between the two pairs of semiconductor switches 78 with the respective bridge branch 72.

The second terminals 80 are made of a copper plate and designed substantially dumbbell-shaped and arranged parallel to the housing wall 48. At the free ends are pins which are parallel to the axis of rotation 28, and which are enclosed by a support of the circuit board 56. Between the two dumbbell-like ends of each second terminal 80 is an eyelet 82 of the second terminal 80 with a central recess. The edge of the eyelet 82 covers the edge of an opening 84 of the circuit board 56, which extends therethrough.

In the assembled state, one of the first connections 52 is in each case electrically contacted with one of the second connections 82 by means of a non-rigid contact element 86 shown in perspective in FIG. 5. In other words, the electric romotor 30 six of these limp contact elements 86 on. Each of the pliable contact elements 86 is provided and suitable to carry an electric current of at least 100 A maximum. Each of the pliable contact elements 86 has a rigid first contact portion 88 and a rigid second contact portion 90, both made of copper. In between, a third contact section 92 made of a copper braid is arranged and welded to both the first and the second contact section 88, 92. The first contact section 88 has an eyelet 94 in the form of a recess, which serves to produce a press fit with one of the first connections 52 in each case. The second contact portion 90 has a sleeve 96 in the form of a hollow cylindrical projection and serves to receive a screw 98 or a bolt (FIGS. 7, 8).

Figure 6 shows a view into the electronics compartment 50 of the electromotive refrigerant compressor 12. Visible, the first terminals 52, which through the

Housing wall 48 are guided. In the six-phase motor or rotating field winding, a total of six such first terminals 52 are present. For assembly, one of the pliable contact element 86 is mechanically mechanically connected to one of the first connections 52, for which the respective end of the first connection 52 located inside the electronics compartment 50 is introduced into the eyelet 94 of the first contact section 88 to form a press fit and thus compressed , In this case, an electrical contacting of the first terminal 52 with the respective non-rigid contact element 86 takes place. Only three of these flexible contact elements 86 are visible in FIG. 6, while the contact elements 50 are removed at three further positions, so that the view of the first connections 52 is free, over

Housing bushings in the electronics compartment 50 out (pushed through) and are surrounded by an insulating section.

In Fig. 7, the mounting of the circuit board 56 in the electronics compartment 50 is shown. For this purpose, the circuit board 56 is set with the recess 62 on the dome 60 and placed on the spacer elements 64. One of the arranged within the bushing 96 of the second contact portion 90 screws 98 is replaced by a the openings 84 of the circuit board and the eyelet 82 of the second terminals 80 out. The screw head 100 of the screw 98 arranged parallel to the rotation axis 28 abuts indirectly via a first heat-conducting pad 102 or a heat-conducting paste on the housing wall 48 and is supported by means of this. The first heat-conducting pad 102 serves to electrically insulate the screw 98 made of a steel from the housing wall 48 made of aluminum.

As can be seen in Fig. 8, the bushing 96 is inserted into the opening 84 of the circuit board 56 until it rests against the free end of the eyelet 82 of the second terminal 80. The circumference of the eyelet 96 is thus surrounded by the formation of a clearance fit of the circuit board 56. The reaching through the eyelet 82 end of

Screw 98 is provided with a nut, not shown, and consequently the second contact portion 90 and the second terminal 80 screwed together, so mechanically connected to each other. In this case also takes place an electrical contact. During operation, a heat dissipation of the second terminal 80 and consequently of the associated bridge branch 72 of the bridge circuit 70 to the housing wall 48 and from there to the refrigerant 10 takes place via the screw 98 and the first heat-conducting pad 102.

In FIG. 9, three of the pliable contact elements 86 mounted on the second terminals 80 are shown in a view from the housing wall 48. It can be seen that the eyelet 96 has a greater distance from the axis of rotation 28, which leads through the recess 62 of the circuit board 56, as the eyelet 94 of the pliable contact element 86. Consequently, the first terminal 52 has a smaller distance from the rotation axis 28 than As a result, the second terminal 80 and the respective bridge branches 72 occupy a comparatively large distance from the axis of rotation 28, for which reason a heat dissipation from the bridge circuit 70 to the housing 30 is improved.

Furthermore, the four semiconductor switches 78 of each bridge branch 72 can be seen, wherein four of these groups of four are shown covered by a second Wärmeleitpads 104. The second heat-conducting pads 104 are located in the assembly ge state on the housing wall 48, and via which a dehumidification of the semiconductor switch 78 takes place. At the center of each of these groups of four is the support point of the printed circuit board 56 on the respective spacer 64, which are arranged on a circular line around the recess 72 of the printed circuit board 56 around. The surface of the second Wärmeleitpads 104 is greater than that of the group of four of the semiconductor switch 78, so that the second Wärmeleitpads 04 edge also overlap copper tracks or copper surfaces for power management and abut against this. This allows good heat dissipation (heat dissipation) from the circuit board 56 to the housing wall 48th

FIG. 10 shows in perspective from the side of the housing cover 94 the pliable contact element 86 which is fastened to the second connection 80. Other components of the circuit board 56 are omitted. It can clearly be seen that the bush 96 abuts the end of the eyelet 82 of the second terminal 80. The second terminal 80 is electrically contacted by means of conductor tracks not shown in detail with the semiconductor switches 74 of one of the bridge branches 72, which are covered by the second Wärmeleitpads 104. Centered between the semiconductor switches 78, the free end 66 of one of the spacer elements 64 is arranged. Due to the flexible third contact portion 92, a movement of the second terminal 80 with respect to the first terminal 52 is enabled, which is rigidly connected to the first contact portion 88 of the flexible contact member 86 mechanically.

The invention is not limited to the embodiment described above. Rather, other variants of the invention can be derived therefrom by the person skilled in the art without departing from the subject matter of the invention. In particular, all the individual features described in connection with the exemplary embodiment can also be combined with one another in other ways, without departing from the subject matter of the invention. LIST OF REFERENCE NUMBERS

2 motor vehicle

4 front wheel

6 rear wheel

8 refrigerant circuit

10 refrigerants

12 refrigerant compressor

14 capacitor

16 evaporators

18 bus system

20 vehicle control

22 board network

24 battery

26 safety device

28 rotation axis

30 electric motor

32 rotor

34 stator

35 electrical coil

36 wave

38 compressor head

40 electronics

42 housing

44 inlet

46 process

48 housing wall

50 electronics compartment

52 first connection

54 housing cover

56 circuit board

58 more printed circuit board

60 dome Recess of the printed circuit board

spacer

free end

bridge circuit

bridge branch

buffering capacity

capacitor

Semiconductor switches

second connection

Eyelet of the second connection

Opening of the circuit board pliable contact element first contact portion second contact portion third contact portion

eyelet

Rifle

screw

Screw heads

first heat-conducting pad second heat-conducting pad

Claims

claims

1 . Electric machine (30) of a motor vehicle (2), in particular of a refrigerant compressor (12), with an electronics compartment (50), and with a printed circuit board (56) arranged therein, and with a first attachment (52) held stationary within the electronics compartment (50) ), which is electrically contacted with an electrical coil (35) of a stator (34) and which is contacted by means of a pliable contact element (86) electrically connected to a second Anschiuss (80) of the printed circuit board (56) with a bridge circuit (70 ) is electrically contacted.

2. Electrical machine (30) according to claim 1,

characterized,

the first attachment (52) is guided through a housing wall (48).

3. Electrical machine (30) according to claim 2,

characterized,

that the pliable contact element (86) bears against the housing wall (48) at least in sections by means of a first heat-conducting pad (102).

4. Electrical machine (30) according to one of claims 1 to 3,

characterized,

in that the flexible contact element (86) has a rigid first contact section (88), a rigid second contact section (90) and a flexible third contact section (92) arranged therebetween, the first contact section (88) being mechanically connected to the first terminal (52) and the second contact section (90) is mechanically connected to the second connection (80).

5. Electrical machine (30) according to claim 4,

characterized, that the third contact portion (92) is made of a braid, in particular a copper braid.

6. Electrical machine (30) according to claim 4 or 5,

characterized,

in that the first and / or second contact section (88, 90) has a bushing (96) or eyelet (94), and / or that the first contact section (88) and the first connection (52) are pressed, and / or the second contact portion (90) and the second terminal (80) are screwed.

7. Electrical machine (30) according to one of claims 4 to 6,

characterized,

in that the second contact section (90) has a hollow-cylindrical projection (96) which is arranged inside an opening (84) of the printed circuit board (56).

8. Electrical machine (30) according to one of claims 1 to 7,

characterized,

in that the first and the second connection (52, 80) have different distances to a rotation axis (28).

9. Electrical machine (30) according to one of claims 1 to 8,

characterized,

the bridge circuit (70) comprises DirectFETs (78).

10. Electrical machine (30) according to claim 9,

characterized,

the directFETs (78) are covered by a second heat-conducting pad (104).

1 1. Electric machine (30) according to one of claims 1 to 10,

characterized, in that the printed circuit board (56) is arranged parallel to a plane and is mounted floating relative to the plane, the plane being in particular perpendicular to a rotation axis (28).

12. Electrical machine (30) according to claim 1 1,

characterized,

in that the electronics compartment (50) has a dome (60) running perpendicular to the plane, which protrudes through a recess (62) of the printed circuit board (56), between the dome (60) and the printed circuit board (56) by means of the recess (Fig. 62) in particular a clearance fit is created.

13. Electrical machine (30) according to claim 1 1 or 12,

characterized,

in that the printed circuit board (56) is spaced apart from a wall (48) of the electronics compartment (50) running perpendicular to the plane by means of a spacer element (64), the printed circuit board (56) resting in particular on a free end (66) of the spacer element (64).

14. Refrigerant compressor (12) of a motor vehicle (2), with an electrical machine (30) according to one of claims 1 to 13.