Electric refrigerant compressor

Abstract

The invention relates to a refrigerant compressor (1) which has a drive unit (2) and a compressor unit (3) coupled to the drive unit (2), wherein the drive unit (2) has a motor housing (2.1) through which refrigerant can flow and which accommodates an electric motor (6) with a rotatable shaft (6.1), wherein the compressor unit (3) accommodates a scroll compressor (5) which can be driven by the shaft (6.1), wherein the motor housing (2.1) comprises a housing wall (12) acted upon by sucked-in refrigerant and an inverter unit (4) attached thereto, which receives an inverter board (7.1) to form a fluid-tight inverter housing (4.1), wherein the inverter board (7.1) has a component arrangement formed with heat-producing electronic components, in particular with at least one intermediate circuit capacitor (9.1) and a plurality of power electronic switches (11.1), which component arrangement is arranged perpendicular to the Inverter board (7.1) has at least two different component heights (18; 19) and is received on the housing wall (12) exposed to the refrigerant in a plurality of formations (16; 17) simulating the component heights (18; 19) and is thermally coupled to these.

Description

The invention relates to an electric refrigerant compressor for use in a refrigerant circuit.In electric refrigerant compressors, as are frequently used in air conditioners and heat pump systems, a movable scroll (scroll) is driven by means of an electric motor. A fixed scroll eccentric to the movable scroll cooperates with the movable scroll to form a plurality of chambers so that the chamber volume is decreased due to the rotation of the movable scroll, resulting in compression of a refrigerant therein. The electric motor and the coils are accommodated in a housing which is hermetically sealed apart from the openings for refrigerant. In this case, the drive unit receiving the electric motor can be accommodated in a motor housing and the spirals can be accommodated in a separate compressor housing part, wherein the two housing parts are joined together during assembly. The motor electronics or an inverter for supplying the electric motor with electric current are accommodated in an inverter housing attached separately to the motor housing. Usually, a housing wall of the motor housing forms a part of the inverter housing, so that a fluid-tight partition wall is formed between the motor housing and the inverter housing. Since the partition wall is charged with refrigerant on the inner side of the motor housing through which sucked refrigerant flows, this housing wall can be used as a heat sink on the inverter housing side. It is therefore advantageous to arrange power electronic components of the inverter, such as electronic switches, in particular transistors (IGBTs (insulated-gate bipolar transistors), MOSFETs (metal-oxide-semiconductor field-effect transistors)) and capacitors, in particular intermediate circuit capacitors, which generate power losses in the form of thermal energy during operation, on the side of the inverter housing, preferably directly on the housing wall or separating wall to which the refrigerant is applied. This allows the electronic components to be protected by heat dissipation and creates ideal operating conditions. However, until now this arrangement has not been possible for all heat-generating electronic components, since, for example, intermediate circuit capacitors require a larger installation space because of their dimensions. Therefore, intermediate circuit capacitors are arranged in the region of the electrical connection, which for space reasons is located outside the outer circumference of the motor housing or of the compressor housing. This position is disadvantageous in view of the necessary heat dissipation. On account of this arrangement, relatively large distances have to be overcome for the electrical connection between the electronic components, which makes it difficult to optimally design the interaction between the intermediate circuit capacitors and the electrical power switches, for example, in particular IGBTs (insulated-gate bipolar transistors) and MOSFETs (metal-oxide-semiconductor field-effect transistors) with regard to the requirements of electromagnetic compatibility (EMC).Designs of inverter boards for electric motors of scroll compressors are known in which the electronic components are selected with regard to their dimensions or arrangement in such a way that a planar height profile of the electronic components results. However, such component arrangements have the disadvantage of an increased area requirement, which requires a greater dimensioning of the inverter circuit board. Due to the expansion into the plane, the electronic components to be cooled cannot all be arranged in the limited region of the housing wall to which refrigerant is applied, which would result in inadequate heat dissipation. A reduction in the component spacings likewise does not lead to the desired success, since the risk of closely adjacent electronic components being influenced thermally is increased.The object of the invention is thus to propose an electric refrigerant compressor in which improved cooling and an improvement in the EMC properties of heat-producing electronic components, in particular intermediate circuit capacitors and power electronic switches, of an inverter can be achieved.The object is achieved by an electric refrigerant compressor having the features according to claim 1. Further developments of the electric refrigerant compressor are specified in the dependent claims.An electric refrigerant compressor is proposed, which is provided for compressing a refrigerant in an air conditioning system, in particular a vehicle air conditioning system. The electric refrigerant compressor has a drive unit and a compressor unit connected to the drive unit. The drive unit comprises a motor housing through which refrigerant can flow, which motor housing accommodates an electric motor with a rotatable shaft. The compressor unit accommodates a scroll compressor that can be driven by the shaft. Assembled, the motor housing of the drive unit and the compressor unit form a fluid-tight compressor housing, with a refrigerant inlet and a refrigerant outlet. The refrigerant inlet is preferably formed on the motor housing of the drive unit. The motor housing comprises a housing wall to which sucked-in refrigerant acts and an inverter unit attached thereto, which receives an inverter circuit board forming a fluid-tight inverter housing. The housing wall to which refrigerant is applied thus forms a fluid-tight partition wall between the motor housing and the inverter housing of the inverter unit. This housing wall is referred to below as a housing wall to which refrigerant is applied.The inverter board has a component arrangement formed with heat-producing electronic components, in particular a component arrangement formed with at least one intermediate circuit capacitor and a plurality of power electronic switches, which is oriented perpendicularly to the inverter board. In its vertical orientation, the component arrangement of the heat-producing electronic components has at least two different component heights and is accommodated on the housing wall acted upon by the refrigerant in a plurality of formations simulated to the component heights. In this case, the component arrangement of the heat-producing electronic components is thermally coupled to the formations. According to the invention, all heat-producing electronic components, in particular at least one intermediate circuit capacitor and a plurality of power electronic switches, are arranged facing the housing wall to which the refrigerants are applied and, corresponding to their component height, are accommodated in shaped portions provided for this purpose in order to ensure better heat dissipation. The heat-producing electronic components oriented perpendicularly to the inverter circuit board plane, in particular at least one intermediate circuit capacitor and a plurality of power electronic switches, thus form elevations which are accommodated in the shaped portions of the housing wall acted upon by the refrigerant. For improved heat distribution, the housing wall acted upon perpendicularly to the refrigerant, the heat-producing electronic components have different component heights.The power-electronic switches include, in particular, IGBTs and MOSFETs. The at least one intermediate circuit capacitor has the task of coupling a plurality of electrical networks to one another in terms of energy on a common DC voltage level. The power-electronic switches can also be combined in a so-called power module (power modules). This is an integrated component arrangement with a corresponding number of power semiconductors. In the context of the invention, the power-electronic switches can each be understood as an integrated component arrangement in the form of a power module. It should also be mentioned that the component arrangement can also have more than six individual power electronic switches or power semiconductors. The stated number of six power-electronic switches or power semiconductors relates only to the minimum number for the actuation of three-phase machines.A housing wall acted upon by refrigerant is preferably used as an end wall of the motor housing, so that the installation space for the component arrangement of the heat-producing electronic components, in particular of the at least one intermediate circuit capacitor and the plurality of power electronic switches, is limited to the cross section of the end wall. This requires small distances between the electronic components and expansion in height, i.e. in a direction perpendicular to the inverter board. For this reason, the component arrangement has heat-producing electronic components which form a height profile with at least two different component heights. Due to the different component heights, the risk of thermal influencing of closely adjacent electronic components is reduced and the heat dissipation for the electronic components protruding into the depth of the formations is increased. It is thus essential for the invention that the heat-generating electronic components have at least two different component heights perpendicular to the inverter board, so that heat dissipation via at least two planes is made possible. These planes are located at a distance parallel to the inverter board corresponding to the component height of the relevant heat-generating electronic component. A component arrangement in which heat-generating electronic components on an inverter circuit board have a substantially identical component height in only one plane is not the subject matter of the invention. Thus, in particular, the plurality of power-electronic switches (IGBTs, MOSFETs) and the at least one intermediate circuit capacitor have a substantially not identical component height perpendicular to the inverter circuit board.It can be provided that the plurality of power-electronic switches (IGBTs, MOSFETs) together have a first component height, wherein the at least one intermediate circuit capacitor has a second component height which projects beyond the first component height perpendicularly to the inverter board. Consequently, the molding receiving the at least one intermediate circuit capacitor is formed deeper than the molding for the plurality of power electronic switches.The formations which receive the heat-producing electronic components can be formed as recesses in the housing wall acted upon by the refrigerant. An inner surface of the recesses thus consists of the material of the housing wall to which the cooling agents are applied, wherein this is usually a metal with good thermal conductivity. The heat dissipation of the heat-producing electronic components is promoted by the good thermal conductivity of the housing wall, which is acted upon by refrigerants formed from metal, both on the end faces and on the sides of the heat-producing electronic components.The housing wall, which is acted upon by refrigerant, can have a separate recess for each electronic component, so that each electronic component can be received separately.The individual recesses or formations are preferably separated by a separating wall. This achieves a spatial separation between the electronic components accommodated in the recesses or recesses. Furthermore, it can be provided that a plurality of electronic components of the same general type, for example all power electronic switches, are accommodated in a single cutout or molding in a combined arrangement.Advantageously, the individual recesses or formations are formed such that the at least one intermediate circuit capacitor and the plurality of power electronic switches are each contacted on at least two sides of their surface with the housing wall to which the refrigerant is applied. Thus, the at least one intermediate circuit capacitor and the plurality of power electronic switches can each be contacted by an end face with the housing wall to which the refrigerant is applied, wherein in each case at least one side wall of the at least one intermediate circuit capacitor and of the plurality of power electronic switches are contacted by a side wall of a molding receiving them.Furthermore, it can be provided that the at least one intermediate circuit capacitor and the plurality of power-electronic switches are each accommodated in a form-fitting manner in the formations of the housing wall to which the refrigerant is applied. In this case, the shaped portions formed in the housing wall to which the refrigerant is applied have an inner profile which positively accommodates the elevations of the at least one intermediate circuit capacitor and of the plurality of power-electronic switches, which elevations emerge perpendicularly via the inverter circuit board. The inner profile of the recesses thus corresponds to the negative of the height profile of the component arrangement comprising the at least one intermediate circuit capacitor and the plurality of power-electronic switches.The invention optimizes the power electronic load flow with respect to the distances of the heat producing electronic components. The optimized positioning of the heat-producing electronic components reduces inductive and capacitive coupling effects. Voltage and current peaks between the inverter intermediate circuit and the power electronic switches are thus significantly reduced. This leads to an improvement in electromagnetic compatibility (EMC).According to a preferred embodiment, the at least one intermediate circuit capacitor can be positioned in the region of the center of the housing wall to which refrigerant is applied, wherein the plurality of power-electronic switches are arranged in a semicircular or circular arrangement around the at least one intermediate circuit capacitor. This arrangement is advantageous if the housing wall, which is acted upon by refrigerant, forms an end wall of the motor housing, on which end wall the electric motor is accommodated on the motor housing side. In this case, the refrigerant drawn in flows around the centrally arranged electric motor during operation, so that a refrigerant flow path is formed in the region of the outer circumference of the end wall, which refrigerant flow path has an influence on the heat dissipation at the housing wall on the side of the inverter housing, which housing wall is acted upon by the refrigerant. A refrigerant flow path is thus formed within the motor housing, which runs along the housing wall to which the refrigerant is applied, wherein at least the plurality of power-electronic switches are arranged on the housing wall to which the refrigerant is applied along the course of the refrigerant flow path. This is advantageous since the heat dissipation is greatest in the region of the refrigerant flow path on the housing wall, which is acted upon by the refrigerant, on the inverter housing side.According to the preceding embodiment, in which the refrigerant flows around the electric motor arranged in the center during operation, the course of the refrigerant flow path is formed at the edge of the housing wall acted upon by the refrigerants. Accordingly, the plurality of power electronic switches may be arranged in a semi-circular or circular arrangement along this refrigerant flow path, wherein the at least one intermediate circuit capacitor is located in the middle of the circular or semi-circular arrangement, respectively.According to this particularly simple embodiment of the motor housing, the housing wall acted upon by the refrigerant has a motor bearing which is formed on the housing wall acted upon by the refrigerant on the motor housing side for receiving the electric motor. In this embodiment, the at least one intermediate circuit capacitor is preferably arranged on the inverter housing side of the housing wall to which the refrigerant is applied in the region of the motor bearing formed on the motor housing side of the housing wall to which the refrigerant is applied. The arrangement of the at least one intermediate circuit capacitor on the housing wall acted upon by the refrigerants on the side facing the inverter housing is thus located in the region of the electric motor arranged on the housing wall acted upon by the refrigerants on the opposite side.According to a preferred embodiment, the motor housing has a tangential refrigerant inlet, so that the refrigerant drawn in can flow tangentially into the motor housing. This is advantageous in particular in embodiments in which the electric motor is arranged in the center of the motor housing such that an intermediate space is formed around the circumference of the electric motor between an outer side of the electric motor and an inner side of the motor housing, said intermediate space forming a flow path for the inflowing refrigerant. Unlike in the case of a radial refrigerant inlet in which a refrigerant flow drawn in would impinge on the centrally arranged electric motor, the refrigerant drawn in flows unimpeded into the intermediate space through the tangential refrigerant inlet, with the result that the refrigerant can flow along the refrigerant flow path without influencing.The housing wall acted upon by the refrigerant can be designed as a separate housing cover of the motor housing.The housing wall acted upon by refrigerant can be designed both as part of the motor housing and as a separate housing part which contains the inverter and closes the motor housing. Furthermore, a configuration in the form of a hermetically sealing motor housing and a further housing which is joined onto this housing and accommodates the inverter as an inverter housing is conceivable.For thermal coupling between the heat-producing electronic components and a housing wall to which the refrigerant is applied on a surface, the electronic components can be contacted in a planar manner with the housing wall to which the refrigerant is applied. In addition, it can be provided that a heat-conducting paste is introduced between the heat-producing electronic components and a housing wall acted upon by the surface of the refrigerant.The refrigerant compressor according to the invention is provided in particular for use in a refrigerant circuit of a motor vehicle.Further details, features and advantages of embodiments of the invention are evident from the following description of exemplary embodiments with reference to the associated drawings. The following are shown: FIGS. 1 ato 1 c : schematic representations of different views of a refrigerant compressor according to the prior art, FIG. 2 : shows an inverter circuit board of a refrigerant compressor according to the prior art, FIG. 3 a : shows a schematic illustration of an exemplary embodiment of a refrigerant compressor according to the invention, FIG. 3 b : shows a schematic sectional illustration of an exemplary embodiment of a refrigerant compressor according to the invention, FIG. 3 c : shows a further schematic sectional illustration of an exemplary embodiment of a refrigerant compressor according to the invention, FIG. 3 d : shows a schematic illustration of an exemplary embodiment of an inverter board of a refrigerant compressor according to the invention, FIG. 3 e : shows a schematic plan view illustration of the housing wall of the inverter housing of a refrigerant compressor, which housing wall is acted upon by the refrigerants, according to the invention, and FIG. 3 f : shows a schematic top view illustration of the housing wall of the motor housing of a refrigerant compressor, which housing wall is acted upon by the refrigerants, according to the invention.FIGS. 1a to 1c show schematic representations of different views of a refrigerant compressor according to the prior art. The directional indications used for describing the figures axially and radially relate to an orientation of the rotational axis of an electric motor which is accommodated in the refrigerant compressor. Figure 1a shows a refrigerant compressor 1 in longitudinal alignment with a drive unit 2 and a compressor unit 3 attached thereto. The drive unit comprises a motor housing 2.1, to which an inverter unit 4 with an inverter housing 4.1 is attached in axial alignment with respect to an electric motor 6 accommodated in the motor housing 2.1 (see Figure 1b). The compressor unit 3 comprises a compressor housing 3.1, in which a scroll compressor 5 (see FIG. 1 b) is accommodated. The motor housing 2.1 and the compressor housing 3.1 form a fluid-tight unit with a substantially circular cylindrical shape. The inverter housing 4.1, which is joined axially to the motor housing 2.1, accommodates an inverter circuit board 7 (see FIGS. 1 b- 1 d) which extends radially over the circumference of the motor housing 2.1, so that the inverter housing 4.1 also projects radially over the circumference of the motor housing 2.1 and of the compressor housing 3.1. The housing part of the inverter housing 4.1 protruding beyond the radial circumference of the motor housing 2.1 and of the compressor housing 3.1 comprises a plug connection 8, which is provided for the electrical contacting or for the connection of electrical lines. The section A is shown in FIG. 1c.FIG. 1 bshows a schematic view of an axial longitudinal section of the refrigerant compressor 1 shown in FIG. 1 a. From left to right, the inverter circuit board 7 is arranged in the inverter housing 4.1, the electric motor 6 is arranged in the motor housing 2.1 and the scroll compressor 5 coupled via a shaft 6.1 is arranged in the compressor housing 3.1. The inverter circuit board 7 comprises an intermediate circuit capacitor 9, which is arranged in the part of the inverter housing 4.1 that protrudes radially beyond the circumference of the motor housing 2.1 and of the compressor housing 3.1.FIG. 1 cshows a view into the interior of the inverter housing 4.1 along the section A indicated by the dashed line in FIG. 1 a. This is thus an axial plan view of the inverter circuit board 7 in the inverter housing 4.1. As can be seen, the surface provided by the inverter housing 4.1 is completely utilized by the shape of the inverter circuit board 7, so that an outer contour of the inverter circuit board 7 is adapted to an inner contour of the inverter housing 4.1.FIG. 2 shows only the inverter circuit board 7 in a plan view of the side facing the motor housing 2.1. The inverter circuit board 7 comprises an intermediate circuit capacitor 9, which is arranged in the region of the dashed line 10. The intermediate circuit capacitor 9 is thus located outside the circumference of the motor housing 2.1. In other words, the intermediate circuit capacitor 9 is located in the region of the housing part of the inverter housing 4.1 which projects radially beyond the circumference of the motor housing 2.1 and therefore outside the influence region of the housing wall shared between the inverter housing 4.1 and the motor housing 2.1, which can also be referred to as a separating wall. Within the substantially circular partial region of the inverter circuit board 7 there are six power-electronic switches 11 which, due to their arrangement, are located in the region of the housing wall shared between the inverter housing 4.1 and the motor housing 2.1 and face the latter.On the motor housing 2.1 side, the housing wall shared by the inverter housing 4.1 and the motor housing 2.1 is charged with sucked-in refrigerant. The arrow 14 illustrates a possible flow path of sucked refrigerant in the motor housing 2.1 with respect to the relative position of the inverter circuit board 7 in the inverter housing 4.1. The power-electronic switches 11 located on the side of the inverter housing 4.1 on the housing wall to which the refrigerant is applied are thus able to dissipate heat that arises on the housing wall to which the refrigerant is applied. However, this does not apply to the intermediate circuit condenser 9, which is located outside the housing wall, which is acted upon by the refrigerant, in the region 10, so that direct contact with the housing wall, which is acted upon by the refrigerant, is not possible for heat dissipation.FIG. 3 ashows a schematic representation of an exemplary embodiment of a refrigerant compressor 1 according to the invention. The refrigerant compressor 1 has a drive unit 2 with a motor housing 2.1 and a compressor unit 3 coupled to the drive unit 2, wherein the compressor unit 3 comprises a compressor housing 3.1 for receiving a scroll compressor 5 (see FIG. 3 b ). The motor housing 2.1 and the compressor housing 3.1 have a substantially circular cylindrical shape. An inverter unit 4 with an inverter housing 4.1 is also attached to the motor housing 2.1 of the drive unit 2. The inverter housing 4.1 projects radially beyond the circumference of the motor housing 2.1 and of the compressor housing 3.1. A plug connection 8 formed on the inverter housing 4.1 serves for the electrical contacting of an inverter circuit board 7 accommodated in the inverter housing 4.1 (see FIGS. 3 b, 3 c, 3 d). The inverter housing 4.1 is closed in a fluid-tight manner by a housing cover 4.2. A tangential refrigerant inlet 13 is formed on the periphery of the motor housing 2.1. From the outside, the refrigerant compressor 1 according to the invention differs only insignificantly from the refrigerant compressor 1 shown in FIG. 1 a. Recurring features are therefore identified by the same reference numerals. The section B is shown in FIG. 3c.FIG. 3 bshows a schematic sectional illustration of an exemplary embodiment of a refrigerant compressor 1, which is an axial longitudinal section, so that a view into the interior of the refrigerant compressor 1 is made possible. An inverter board 7.1 containing the motor electronics is accommodated in the fluid-tight inverter housing 4.1 which is attached to the motor housing 2.1. The compressor housing 3.1 is attached to the further side of the motor housing 2.1, wherein a scroll compressor 5 is accommodated in the compressor housing 3.1. The scroll compressor 5 is coupled via a drive shaft 6.1 to an electric motor 6 accommodated in the motor housing 2.1. The motor housing 2.1 has an electric motor bearing 15, on which the electric motor 6 is accommodated in the interior of the motor housing 2.1 in such a way that a space is formed between the outer circumference of the electric motor 6 and the radially inner circumference of the motor housing 2.1. During operation, this intermediate space is filled with refrigerant, wherein a refrigerant flow path for sucked refrigerant is formed along the intermediate space. The refrigerant flow path 14 (see FIG. 3 c ) runs along an end wall of the motor housing 2.1, so that this housing wall is permanently charged with refrigerant during operation. This housing wall 12 to which coolant is applied, which is highlighted in regions by the transverse hatching, forms a fluid-tight partition between the motor housing 2.1 and the inverter housing 4.1 attached thereto. The profile of the housing wall 12 on which the refrigerant acts facing the inverter housing 4.1 has shaped portions 16 and 17 which are provided for receiving heat-generating electronic components of the inverter circuit 7.1. Thus, the inverter circuit board 7.1 has two intermediate circuit capacitors 9.1 and six power-electronic switches 11.1, which rise perpendicularly from the plane of the inverter circuit board 7.1 and extend in the axial direction. The power electronic switches 11.1 are accommodated in a molding 17, wherein the dashed line 18 shows a first component height of the power electronic switches 11.1 perpendicular to the inverter board plane. The first component height 18 corresponds substantially to the axial depth of the formation 17 of the housing wall 12 to which the refrigerant is applied. The two intermediate circuit capacitors 9.1 are each accommodated in a formation 16 of the housing wall 12 to which the refrigerant is applied. The dashed line 19 identifies a second component height, which corresponds to the overall height of the two intermediate circuit capacitors 9.1 perpendicular to the inverter circuit board plane. Furthermore, the second component height 19 corresponds substantially to the axial depth of the formations 16 in the housing wall 12 acted upon by the refrigerant.FIG. 3 cshows a further schematic sectional illustration of a refrigerant compressor according to the invention. This is a sectional view of the inverter housing 4.1 along the section B shown in FIG. 3 a. The sectional view enables a view of the inverter circuit board 7.1 accommodated in the inverter housing 4.1. A part of the inverter circuit board 7.1 is located in the region of the housing wall 12 which is subjected to the cooling medium. The arrow 14 identifies the flow path of a cooling medium which is supplied to the motor housing 2.1 via the tangential cooling medium inlet 13. It can be seen that only a part of the inverter circuit board 7.1 is assigned to the region of the housing wall 12 exposed to the refrigerant or to the course of the refrigerant flow path in order to ensure a heat transfer and thus a heat dissipation. Thus, a part of the inverter circuit board 7.1 is not located in the area of influence of the housing wall 12 acted upon by the refrigerants, but in the inverter housing part of the inverter housing 4.1 protruding beyond the outer circumference of the motor housing 2.1.FIG. 3 d shows a schematic representation of an exemplary embodiment of an inverter circuit board 7.1 in a plan view of the side facing the housing wall 12 exposed to the refrigerant, solely without the surrounding inverter housing 4.1. On this side of the inverter board 7.1, the two intermediate circuit capacitors 9.1 and the six power electronic switches 11.1 are arranged in addition to further electronic components. The power-electronic switches 11.1 are IGBTs or MOSFETs. Together with the six power-electronic switches 11.1, which are arranged in the region of the circular outer contour of the inverter board 7.1 oriented in the form of a semicircle with respect to the edge of the inverter board 7.1, the two intermediate circuit capacitors 9.1 form a component arrangement of heat-generating electronic components. According to the invention, the component arrangement of the six power-electronic switches 11.1 and of the two intermediate circuit capacitors 9.1 is positioned on the inverter circuit board 7.1 in the region of influence of the housing wall 12 acted upon by the refrigerants when the inverter circuit board 7.1 is mounted in the inverter housing 4.1. In this case, the six power-electronic switches 11.1 and the two intermediate circuit capacitors 9.1 face the housing wall 12 to which the refrigerant is applied. Unlike the embodiment of a refrigerant compressor 1 of the prior art shown in FIGS. 1 ato 1 c, the heat-generating electronic components, comprising the six power-electronic switches 11.1 and the two intermediate circuit capacitors 9.1, are arranged in the invention in a compact component arrangement opposite the housing wall 12 to which the refrigerant is applied, in order to achieve dissipation of heat arising by the refrigerant flow generated in the motor housing 2.1.The six power electronic switches 11.1 extend perpendicularly from the inverter board 7.1, wherein the six power electronic switches 11.1 have the same component heights. The two intermediate circuit capacitors 9.1 likewise extend perpendicularly from the inverter board 7.1, wherein the component height of the intermediate circuit capacitors 9.1 protrudes beyond the component height of the power electronic switches 11.1 perpendicularly to the inverter board 7.1. The component arrangement of the six power electronic switches 11.1 and of the two intermediate circuit capacitors 9.1 thus has a height profile with two different component heights 18 and 19 (see FIG. 3b). The arrangement of the intermediate circuit capacitors 9.1 and the power electronic switches 11.1 on the inverter circuit board 7.1 is oriented on the course of the refrigerant flow path 14 in the motor housing 2.1.FIG. 3 e shows a schematic top view illustration of the housing wall 12 of the inverter housing 4.1 of a refrigerant compressor 1 according to the invention, which housing wall is acted upon by the refrigerant. On this side, the housing wall 12 on which the refrigerant acts has two shaped portions 16, which are provided for receiving the two intermediate circuit capacitors 9.1. The shaped portions 16 are designed as recesses in the material of the housing wall 12 to which the cooling medium is applied and correspond with regard to their arrangement and dimensioning to the two intermediate circuit capacitors 9.1 arranged on the inverter circuit board 7.1 in such a way that they are accommodated in the shaped portions 16 when the inverter circuit board 7.1 is mounted in the inverter housing 4.1. The dimensioning of the formations 16 is selected such that the contact area between the formations 16 and the surface of the intermediate circuit capacitors 9.1 is as large as possible. At least two sides of the two intermediate circuit capacitors 9.1 are in contact with the surface of the shaping 16 that receives them. These are in each case the end face and a side face of the rectangular intermediate circuit capacitors 9.1. In order to produce a thermal coupling, the intermediate circuit capacitors 9.1 are contacted with the housing wall 12 to which the refrigerant is applied at least with their rectangular cover surfaces in the formations 16. Furthermore, it can be provided that at least one side surface of the intermediate circuit capacitors 9.1 is contacted with a surface of the formations 16. The shaped portions 16 are preferably dimensioned such that they receive the intermediate circuit capacitors 9.1 in a form-fitting manner. As a measure for improving the thermal coupling, a heat-conducting paste can be introduced in each case between the intermediate circuit capacitors 9.1 and the formations 16 receiving them.Furthermore, the housing wall 12 of the inverter housing 4.1, which is acted upon by the coolant, has three shaped portions 17 for receiving the power electronic switches 11.1. The shaped portions 17 are formed as a recess made of the material of the housing wall 12 of the inverter housing 4.1 acted upon by the coolant in such a way that they receive the power electronic switches 11.1 when the inverter circuit board 7.1 is mounted in the inverter housing 4.1. Each shaping 17 accommodates two power-electronic switches 11.1. The elevations of the power-electronic switches 11.1 perpendicular to the plane of the inverter circuit board 7.1 are thus almost completely accommodated in the molding 17. In order to promote the thermal coupling, a heat-conducting paste can be introduced between the power-electronic switches 11.1 and the formations 17 receiving them. The formations 17 are formed along the refrigerant flow path 14 formed in the motor housing 2.1 during operation.The formations 16 and 17 have no cross connection and are formed differently deep in the housing wall 12 to which the refrigerant is applied due to the different component heights of the two intermediate circuit capacitors 9.1 and the six power electronic switches 11.1. Consequently, the protrusions 16 receiving the intermediate circuit capacitors 9.1 are formed deeper than the protrusions 17 for the six power electronic switches 11.1. The further configuration of the housing wall 12 acted upon by the refrigerant is configured such that the plate-shaped inverter circuit board 7.1 is oriented perpendicular to the axis of rotation of the electric motor 6 (see FIG. 3 b) in the assembled state.Due to the spatial separation between the intermediate circuit capacitors 9.1 and the power electronic switches 11.1 achieved by the formations 16 and 17, the risk of mutual thermal influence is low. This advantageous effect is additionally enhanced by the different component heights 18 and 19. Furthermore, contacting side surfaces of the intermediate circuit capacitors 9.1 and the power electronic switches 11.1 with the surfaces within the formations 16 and 17 contributes to improved heat dissipation, since the heat transfer surface is enlarged overall.FIG. 3 f shows a schematic top view illustration of the housing wall 12 of the motor housing 2.1 acted upon by the refrigerant. The side of the housing wall 12 exposed to the refrigerant facing the motor housing 2.1 is thus shown. On this side, the electric motor bearing 15 is designed to receive the electric motor 6.According to the invention, the intermediate circuit capacitors 9.1 (see FIG. 3d) are arranged substantially in the region of the center of the motor housing 2.1 opposite the electric motor bearing 15. This improves the heat dissipation to the refrigerant in comparison to the design shown in FIGS. 1 ato 1 c, in which the intermediate circuit capacitor 9 is located outside the circumference of the motor housing 2.1. Furthermore, the power electronic switches 11.1 are arranged semicircularly on the outer radius, radially close to the inner walls of the compressor suction chamber. The position is thus optimized to the range of maximum heat emission to the refrigerant. In addition, the power electronic load flow is optimized with respect to the distances between the intermediate circuit capacitors 9.1 and the power electronic switches 11.1 in order to reduce inductive and capacitive interference, which is important for sufficient electromagnetic compatibility (EMC).The housing wall 12 acted upon by the refrigerant can be designed as a separate housing part which ensures a fluid-tight seal in its arrangement between the motor housing 2.1 and the inverter housing 4.1. For fastening, a screw connection to the motor housing 2.1 can be provided. For this purpose, the housing wall 12 acted upon by the refrigerant can have corresponding screw feedthroughs.List of reference characters1 Refrigerant compressor 2 Drive unit 2.1 Motor housing 3 Compressor unit 3.1 Compressor housing 4 Inverter unit 4.1 Inverter housing 4.2 Housing cover 5 Scroll compressor 6 Electric motor 6.1 Rotatable shaft 7 Inverter printed circuit board 7.1 Inverter printed circuit board 8 Electrical plug connection 9 Intermediate circuit capacitor 9.1 Intermediate circuit capacitor 10 Dashed region 11 Power electronic switch 11.1 Power electronic switch 12 Refrigerant-loaded housing wall 13 Tangential refrigerant inlet 14 Arrow / refrigerant flow path 15 Electric motor bearing 16 Formation 17 Formation 18 First component height 19 Second component height

Claims

Refrigerant compressor (1) having a drive unit (2) and a compressor unit (3) coupled to the drive unit (2), wherein the drive unit (2) has a motor housing (2.1) through which refrigerant can flow, which motor housing receives an electric motor (6) having a rotatable shaft (6.1), wherein the compressor unit (3) receives a scroll compressor (5) which can be driven by the shaft (6.1), wherein the motor housing (2.1) comprises a housing wall (12) to which sucked-in refrigerant acts and an inverter unit (4) which is attached thereto and which receives an inverter board (7.1) forming a fluid-tight inverter housing (4.1), wherein the inverter board (7.1) has a component arrangement formed with heat-producing electronic components, in particular a component arrangement formed with at least one intermediate circuit capacitor (9.1) and a plurality of power-electronic switches (11.1), which has at least two different component heights (18; 19) perpendicular to the inverter board (7.1) and is accommodated on the housing wall (12), which is acted upon by refrigerant, in a plurality of formations (16; 17) which are simulated to the component heights and is thermally coupled to these formations.Refrigerant compressor (1) according to claim 1, characterised in that the plurality of power-electronic switches (11.1) together have a first component height (18), wherein the at least one intermediate circuit capacitor (9.1) has a second component height (19), which projects beyond the first component height (18) perpendicularly to the inverter board (7.1).Refrigerant compressor according to Claim 1 or 2, characterized in that the formations (16; 17) are designed as recesses in the housing wall (12) which is acted upon by refrigerant.Refrigerant compressor (1) according to one of Claims 1 to 3, characterized in that the at least one intermediate circuit capacitor (9.1) and the plurality of power-electronic switches (11.1) are in contact with the housing wall (12) to which the refrigerant is applied in each case on at least two sides of their surface.Refrigerant compressor (1) according to one of Claims 1 to 4, characterized in that the at least one intermediate circuit capacitor (9.1) and the plurality of power-electronic switches (11.1) are each accommodated in the formations (16; 17) in a positively locking manner.Refrigerant compressor (1) according to one of Claims 1 to 5, characterized in that the at least one intermediate circuit capacitor (9.1) is positioned in the region of the centre of the housing wall (12) to which refrigerant is applied, wherein the plurality of power-electronic switches (11.1) are arranged in a semicircular or circular arrangement around the at least one intermediate circuit capacitor (9.1).Refrigerant compressor (1) according to one of Claims 1 to 6, characterized in that a refrigerant flow path (14) is formed within the motor housing (2.1), said refrigerant flow path running along the housing wall (12) acted upon by the refrigerant, wherein at least the plurality of power-electronic switches (11.1) are arranged on the housing wall (12) acted upon by the refrigerant along the course of the refrigerant flow path (14).Refrigerant compressor (1) according to one of Claims 1 to 7, characterized in that the at least one intermediate circuit capacitor (9.1) on the housing wall (12), which is subjected to the action of the refrigerant, is positioned in the region of an electric motor bearing (15), which is formed on the housing wall (12), which is subjected to the action of the refrigerant, on the inverter housing side.Refrigerant compressor (1) according to one of Claims 1 to 8, characterized in that the motor housing (2.1) has a tangential refrigerant inlet (13).Refrigerant compressor (1) according to one of Claims 1 to 9, characterized in that the housing wall (12), which is acted upon by refrigerant, is designed as a separate housing cover of the motor housing (2.1).Refrigerant compressor (1) according to one of Claims 1 to 10, characterized in that a heat-conducting paste is introduced for thermal coupling between the heat-producing electronic components and a housing wall (12) which is acted upon by the refrigerants.Use of a refrigerant compressor (1) according to any one of claims 1 to 11 in a refrigerant circuit of a vehicle.

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