Electrical refrigerant compressor

Abstract

To provide an electrical refrigerant compressor in which improved cooling and an improvement in the EMC properties of heat-producing electronic components, in particular DC link capacitors and electronic power switches, of an inverter can be achieved.SOLUTION: An electrical refrigerant compressor includes a drive unit, a compressor unit, and a motor housing (2.1). The compressor unit forms a shaft (6.1) and a fluid-tight inverter housing (4.1). An inverter circuit board (7.1) has heat-producing electronic components, in particular, at least one DC link capacitor (9.1) and a plurality of electronic power switches (11.1), and has at least two different component heights (18; 19) perpendicular to the inverter circuit board (7.1), is accommodated in a plurality of moldings (16; 17) which are formed according to the component heights (18; 19), on a refrigerant-exposed housing wall (12), and is thermally coupled to the moldings.SELECTED DRAWING: Figure 3b

Description

Technical Field

[0001] The present invention relates to an electric refrigerant compressor, and more particularly to an electric refrigerant compressor capable of achieving improvement in cooling of electronic components that generate heat of an inverter, particularly a DC link capacitor and an electronic power switch, and improvement in EMC characteristics.

Background Art

[0002] In an electric refrigerant compressor often used in an air conditioning system or a heat pump system, a movable spiral (scroll) is driven by an electric motor. A fixed spiral eccentric with respect to the movable spiral interacts with the movable spiral to form a plurality of chambers. As the movable spiral rotates, the volume of the chambers decreases, and the refrigerant therein is compressed. The electric motor and the spiral are housed in a housing sealed except for an opening for the refrigerant. A drive unit that houses the electric motor can be housed in a motor housing, and the spiral can be housed in a separate compressor housing part. The two housing parts are joined together during assembly. Motor electronics or an inverter for supplying current to the electric motor is housed in an inverter housing separately joined to the motor housing.

[0003] Typically, the housing wall of the motor housing forms part of the inverter housing, and a fluid-tight partition is formed between the motor housing and the inverter housing. Since the partition plate is exposed to the refrigerant inside the motor housing and the suctioned refrigerant flows through it, this housing wall can be used as a heat sink on the inverter housing side. Therefore, it is advantageous to directly arrange power electronics components of the inverter that generate power losses in the form of thermal energy during operation, such as electronic switches, especially transistors (IGBT (Insulated Gate Bipolar Transistor), MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor)) and capacitors, especially DC link capacitors, on the side of the inverter housing, preferably on the housing wall or partition exposed to the refrigerant. As a result, the electronic components are protected by heat dissipation and ideal operating conditions can be created.

[0004] However, until now, for example, a DC link capacitor requires a relatively large installation space due to its dimensions, so such an arrangement has not been possible for all heat-generating electronic components. Therefore, the DC link capacitor is arranged in the region of the electrical terminal located outside the outer periphery of the motor housing or the compressor housing for space reasons. This position is disadvantageous in terms of the required heat dissipation. Due to this arrangement, a relatively large distance has to be covered for the electrical connection between the electronic components. For example, it becomes difficult to optimally design the interaction between the DC link capacitor and the power switch, especially IGBT (Insulated Gate Bipolar Transistor) and MOSFET (Metal Oxide Semiconductor Field-Effect Transistor), from the perspective of electromagnetic compatibility (EMC) requirements.

[0005] Regarding the inverter circuit board for the motor of a scroll compressor, there is a known concept in which electronic components are selected in terms of dimensions or arrangement so that the height profiles of the electronic components are made uniform. However, such component arrangements have the drawback of increasing the required area because they require an increase in the dimensions of the inverter circuit board. Due to the planar spread, all the electronic components to be cooled cannot be arranged in the limited area of the housing wall where the refrigerant is exposed, resulting in insufficient heat dissipation. Also, even if the distance between components is reduced, the risk of closely adjacent electronic components affecting each other thermally increases, which does not lead to desirable results.

Summary of the Invention

Problems to be Solved by the Invention

[0006] An object of the present invention is to propose an electric refrigerant compressor that can achieve improved cooling of electronic components that generate heat in the inverter, particularly the DC link capacitor and the electronic power switch, and improved EMC characteristics. This object is achieved by an electric refrigerant compressor having the features described in claim 1. The development of the electric refrigerant compressor is defined in the dependent claims.

[0007] The electric refrigerant compressor of the present invention includes a drive unit (2) and, a compressor unit (3) coupled to the drive unit (2), The drive unit (2) includes a motor housing (2.1) that houses an electric motor (6) having a rotatable shaft (6.1) through which refrigerant can flow, The compressor unit (3) houses a scroll compressor (5) that can be driven by the shaft (6.1), The motor housing (2.1) has a housing wall (12) exposed to the suctioned refrigerant and is joined thereto and has an inverter circuit board (7.1), A fluid-tight inverter housing (4.1) is formed, and the inverter circuit board (7.1) has heat-generating electronic components, in particular at least one DC link capacitor (9.1) and a plurality of electronic power switches (11.1). The inverter circuit board (7.1) has at least two different component heights (18; 19) perpendicular to the inverter circuit board (7.1), and is housed in a plurality of moldings (16; 17) formed according to the component heights on the refrigerant-exposed housing wall (12), and is thermally coupled to the moldings.

[0008] The plurality of electronic power switches (11.1) together have a first component height (18), and at least one DC link capacitor (9.1) has a second component height (19) protruding beyond the first component height (18) perpendicular to the inverter circuit board (7.1). The plurality of moldings (16; 17) are designed as recesses in the refrigerant-exposed housing wall (12), and the at least one DC link capacitor (9.1) and the plurality of electronic power switches (11.1) are each in contact with the refrigerant-exposed housing wall (12) on at least two sides of their surfaces, and the at least one DC link capacitor (9.1) and the plurality of electronic power switches (11.1) are each shape-fittingly housed in the moldings (16; 17).

[0009] An electric refrigerant compressor for compressing refrigerant in an air conditioning system, in particular a vehicle air conditioning system, has been proposed. The electric refrigerant compressor has a drive unit and a compressor unit connected to the drive unit. The drive unit includes a motor housing that houses an electric motor having a rotatable shaft through which refrigerant can flow. The compressor unit houses a scroll compressor that can be driven by the shaft. When joined together, the motor housing of the drive unit and the compressor unit form a fluid-tight compressor housing having a refrigerant inlet and a refrigerant outlet. The refrigerant inlet is preferably formed in the motor housing of the drive unit. The motor housing is composed of a housing wall exposed to the sucked refrigerant and an inverter unit joined thereto and accommodating the inverter circuit board, forming a fluid-tight inverter housing. Therefore, the housing wall exposed to the refrigerant forms a fluid-tight partition between the motor housing and the inverter housing of the inverter unit. Hereinafter, this housing wall is referred to as the refrigerant-exposed housing wall. The inverter circuit board has a component arrangement formed by heat-generating electronic components, particularly at least one DC link capacitor and a plurality of electronic power switches, and is oriented in a direction perpendicular to the inverter circuit board. In that vertical direction, the component arrangement of the heat-generating electronic components has at least two different component heights and is accommodated in a plurality of moldings formed according to the component heights on the refrigerant-exposed housing wall. The component arrangement of the heat-generating electronic components is thermally coupled to the moldings.

[0010] According to the present invention, all heat-generating electronic components, particularly at least one DC link capacitor and a plurality of electronic power switches, are arranged facing the refrigerant-exposed housing wall in order to ensure better heat dissipation, and are accommodated in the moldings provided therefor according to their component heights. Since the heat-generating electronic components, particularly at least one DC link capacitor and a plurality of electronic power switches, are oriented perpendicular to the surface of the inverter circuit board, heights are formed and they are accommodated in the moldings of the refrigerant-exposed housing wall. In order to improve the heat distribution perpendicular to the refrigerant-exposed housing wall, the heat-generating electronic components have different component heights. The electronic power switches include, in particular, IGBTs and MOSFETs. At least one DC link capacitor serves to energize multiple electrical circuit networks to each other at a common DC voltage level. The electronic power switches can also be combined into so-called power modules. This is an integrated component arrangement with the corresponding number of power semiconductors. In the context of the present invention, the electronic power switches can each be understood as component arrangements integrated in the form of power modules. It should also be mentioned that the component arrangement can also have more than six individual electronic power switches or power semiconductors. The number of six electronic power switches or power semiconductors described relates to the minimum number for operating a three-phase machine.

[0011] The end wall of the motor housing preferably functions as a refrigerant-exposed housing wall. Therefore, the installation space for heat-generating electronic components, in particular the component arrangement of at least one DC link capacitor and multiple electronic power switches, is limited to the cross-section of the end wall. For this reason, it is necessary to reduce the distance between the electronic components and extend in the height direction, that is, perpendicular to the inverter circuit board. For this reason, the component arrangement has heat-generating electronic components that form a height profile with at least two different component heights. Thanks to the different component heights, the risk that closely adjacent electronic components thermally affect each other is reduced, and the heat dissipation of the electronic components protruding into the depth of the molding increases.

[0012] Therefore, in order to enable heat dissipation through at least two planes, it is essential for the present invention that the heat-generating electronic components have at least two different component heights perpendicular to the inverter circuit board. These planes are located at a distance parallel to the inverter circuit board corresponding to the component height of the associated heat-generating electronic components. A component arrangement in which the heat-generating electronic components on the inverter circuit board have substantially equal component heights only on one plane does not form the subject matter of the present invention. In particular, multiple electronic power switches (IGBTs, MOSFETs) and at least one DC link capacitor therefore do not have substantially equal component heights in the direction perpendicular to the inverter circuit board.

[0013] A plurality of electronic power switches (IGBTs, MOSFETs) can be combined to have a first component height, and at least one DC link capacitor can be provided to have a second component height that protrudes perpendicular to the inverter circuit board and exceeds the first component height. Thus, the molding that houses at least one DC link capacitor is deeper than the molding for the plurality of electronic power switches.

[0014] The molding that houses the heat-generating electronic components can be designed as a recess in the refrigerant-exposed housing wall. Thus, the inner surface of the recess is composed of the material of the refrigerant-exposed housing wall, which is usually a metal with good thermal conductivity. The heat dissipation of the heat-generating electronic components is promoted by the good thermal conductivity of the metal refrigerant-exposed housing wall at both the end face and the side face of the heat-generating electronic components. The refrigerant-exposed housing wall can have individual recesses for each electronic component so that each electronic component can be housed individually.

[0015] Individual recesses or moldings are preferably separated by partitions. As a result, a spatial separation between the electronic components housed in the recesses or cutouts is achieved. Also, a plurality of electronic components of the same type, for example, all the electronic power switches, can be housed together in a single notch or molding. Advantageously, the individual recesses or moldings are designed such that at least one DC link capacitor and the plurality of electronic power switches each contact the refrigerant-exposed housing wall on at least two sides of their surfaces. Thus, at least one DC link capacitor and the plurality of electronic power switches can each contact the refrigerant-exposed housing wall at the end face, and in each case, at least one side wall of at least one DC link capacitor and the plurality of electronic power switches contacts the side wall of the molding that houses them.

[0016] Also, each of at least one DC link capacitor and a plurality of electronic power switches can be provided so as to be accommodated in a shape - conforming manner in the molding of the refrigerant - exposed housing wall. In this case, the molding formed on the refrigerant - exposed housing wall has an inner contour that precisely accommodates, in terms of shape, the height that at least one DC link capacitor and a plurality of electronic power switches project vertically beyond the inverter circuit board. Therefore, the inner shape of the recess corresponds negatively to the height profile of the component arrangement consisting of at least one DC link capacitor and a plurality of electronic power switches.

Advantages of the Invention

[0017] According to the present invention, in relation to the distance between heat - generating electronic components, the flow of power - electronic loads is optimized. Since the positions of the heat - generating electronic components are optimized, the effects of inductive coupling and capacitive coupling are reduced. The voltage peaks and current peaks between the converter DC link and the electronic power switches are thus significantly reduced. As a result, the electromagnetic compatibility (EMC) is improved.

[0018] According to a preferred embodiment, at least one DC link capacitor can be arranged in the central region of the refrigerant - exposed housing wall, and a plurality of electronic power switches are arranged in a semi - circular or circular shape around at least one DC link capacitor. This arrangement is advantageous when the refrigerant - exposed housing wall forms an end wall of a motor housing in which an electric motor is accommodated on the motor housing side. In this case, the sucked - in refrigerant flows around the centrally arranged electric motor during operation, so that a refrigerant flow path is formed in the region of the outer periphery of the end wall, and this refrigerant flow path affects the heat dissipation of the refrigerant - exposed housing wall on the inverter housing side. For this reason, inside the motor housing, a refrigerant flow path is formed along the refrigerant - exposed side housing wall surface, and at least a plurality of electronic power switches are arranged in the middle of the refrigerant flow path on the refrigerant - exposed side housing wall surface. This is advantageous because the heat dissipation is the greatest in the region of the refrigerant flow path on the refrigerant - exposed housing wall surface on the inverter housing side.

[0019] According to the above-described embodiment in which the refrigerant flows around the electric motor disposed centrally during operation, the course of the refrigerant flow path becomes prominent at the end of the refrigerant-exposed housing wall. Therefore, a plurality of electronic power switches can be arranged in a semi-circular or circular shape along this refrigerant flow path, and at least one DC link capacitor is located at the center of the circular or semi-circular arrangement.

[0020] According to this particularly simple embodiment of the motor housing, the refrigerant-exposed housing wall has a motor bearing formed on the motor housing side of the refrigerant-exposed housing wall for accommodating the electric motor. In this embodiment, at least one DC link capacitor is preferably arranged on the inverter housing side of the refrigerant-exposed housing wall in the region of the motor bearing formed on the motor housing side of the refrigerant-exposed housing wall. Thus, the arrangement of at least one DC link capacitor is located on the side of the refrigerant-exposed housing wall facing the inverter housing in the region of the electric motor disposed on the opposite side of the refrigerant-exposed housing wall.

[0021] According to a preferred embodiment, the motor housing has a tangential refrigerant inlet so that the sucked-in refrigerant can flow into the motor housing in a tangential direction. This is particularly advantageous in an embodiment in which the electric motor is disposed at the center of the motor housing, a gap is formed in the circumferential direction of the electric motor between the outer peripheral side of the electric motor and the inner peripheral side of the motor housing, and this gap forms a flow path for the incoming refrigerant. Unlike the radial refrigerant inlet where the flow of the sucked-in refrigerant bounces back to the centrally disposed electric motor, the sucked-in refrigerant can flow from the tangential refrigerant inlet into the gap without being obstructed, so that the refrigerant can flow along the refrigerant flow path without being affected.

[0022] The refrigerant-exposed housing wall can be designed as a separate housing cover for the motor housing. The refrigerant-exposed housing wall can also be designed as part of the motor housing or as a separate housing component that houses the inverter and closes the motor housing. Further, a design in the form of a hermetically sealed motor housing and a further housing joined to this housing and housing the inverter as an inverter housing is also conceivable.

[0023] For thermal coupling between the heat-generating electronic component and the surface of the refrigerant-exposed housing wall, the electronic component can be in flat contact with the refrigerant-exposed housing wall. Also, a thermal paste can be provided so as to be introduced between the heat-generating electronic component and the surface of the refrigerant-exposed housing wall. The refrigerant compressor according to the present invention is provided particularly for use in a refrigerant circuit of an automobile.

Brief Description of the Drawings

[0024]

Figure 1a

Figure 1b

Figure 1c

Figure 2

Figure 3a

Figure 3b

Figure 3c

Figure 3d

Figure 3e

Figure 3f

Embodiments for Carrying Out the Invention

[0025] Further details, features, and advantages of embodiments of the present invention can be found in the following description of exemplary embodiments with reference to the associated drawings. Figures 1a to 1c are schematic diagrams showing different views of a refrigerant compressor according to the prior art. The axial and radial terms used to explain the figures relate to the direction of the rotation axis of the electric motor housed in the refrigerant compressor. Figure 1a shows the refrigerant compressor 1 with the drive unit 2 and the compressor unit 3 joined together in the longitudinal direction. The drive unit consists of a motor housing 2.1, and an inverter unit 4 having an inverter housing 4.1 is axially joined to the electric motor 6 (see Figure 1b) housed in the motor housing 2.1.

[0026] The compressor unit 3 is composed of a compressor housing 3.1 in which a scroll compressor 5 (see Figure 1b) is housed. The motor housing 2.1 and the compressor housing 3.1 form a substantially cylindrical fluid-tight unit. The inverter housing 4.1 axially joined to the motor housing 2.1 houses an inverter circuit board 7 (see Figures 1b to 1d), and since this inverter circuit board 7 extends radially along the outer periphery of the motor housing 2.1, the inverter housing 4.1 also protrudes radially beyond the outer peripheries of the motor housing 2.1 and the compressor housing 3.1. The housing portion of the inverter housing 4.1 protruding radially outside the motor housing 2.1 and the compressor housing 3.1 constitutes a plug-in terminal 8 provided for electrical contact or connection of electrical cables. Section A is shown in Figure 1c.

[0027] Figure 1b is a schematic diagram showing an axial longitudinal section of the refrigerant compressor 1 shown in Figure 1a. Inside the refrigerant compressor 1, in order from the left, an inverter circuit board 7 is arranged in an inverter housing 4.1, an electric motor 6 is arranged in a motor housing 2.1, and a scroll compressor 5 connected via a shaft 6.1 is arranged in a compressor housing 3.1. The inverter circuit board 7 is composed of a DC link capacitor 9 arranged in a portion of the inverter housing 4.1 that radially protrudes beyond the outer circumferences of the motor housing 2.1 and the compressor housing 3.1.

[0028] Figure 1c is a view showing the inside of the inverter housing 4.1 along the section A indicated by the dashed line in Figure 1a. Therefore, this is a plan view of the inverter circuit board 7 in the axial direction inside the inverter housing 4.1. As can be seen, the area provided by the inverter housing 4.1 is completely occupied by the shape of the inverter circuit board 7, so the outer contour of the inverter circuit board 7 coincides with the inner contour of the inverter housing 4.1.

[0029] Figure 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 consists of a DC link capacitor 9, and this DC link capacitor 9 is arranged in the area of the dashed line 10. The DC link capacitor 9 is thus located outside the outer circumference of the motor housing 2.1. In other words, the DC link capacitor 9 is located in the area of the housing portion of the inverter housing 4.1 that radially protrudes beyond the circumference of the motor housing 2.1, and thus is located outside the affected area of the housing wall that is jointly used between the inverter housing 4.1 and the motor housing 2.1 and can also be called a partition. Inside the substantially circular portion of the inverter circuit board 7, there are six electronic power switches 11, and these switches are, by their arrangement, located in the area of the housing wall that is jointly used between the inverter housing 4.1 and the motor housing 2.1 and face the said housing wall.

[0030] On the side of the motor housing 2.1, there is a housing wall jointly used by the inverter housing 4.1 and the motor housing 2.1, which is exposed to the sucked refrigerant. Arrow 14 indicates the flow path of the refrigerant that may be inhaled into the motor housing 2.1 in the relative positional relationship with the inverter circuit board 7 in the inverter housing 4.1. The electronic power switch 11 arranged on the refrigerant-exposed housing wall surface on the side of the inverter housing 4.1 can dissipate the heat generated on the refrigerant-exposed housing wall surface in this way. However, this does not apply to the DC link capacitor 9. Since the DC link capacitor 9 is located in the region 10 outside the refrigerant-exposed housing wall, it cannot be in direct contact with the refrigerant-exposed housing wall for heat dissipation.

[0031] Figure 3A is a schematic view of an exemplary embodiment of the refrigerant compressor 1 according to the present invention. The refrigerant compressor 1 includes a drive unit 2 having a motor housing 2.1 and a compressor unit 3 coupled to the drive unit 2. The compressor unit 3 includes a compressor housing 3.1 for accommodating a scroll compressor 5 (see Figure 3b). 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 joined to the motor housing 2.1 of the drive unit 2. The inverter housing 4.1 projects radially beyond the circumferences of the motor housing 2.1 and the compressor housing 3.1. The plug-in terminals 8 formed on the inverter housing 4.1 are used for electrical contact with the inverter circuit board 7 (see Figures 3b, 3c, and 3d) housed in the inverter housing 4.1. The inverter housing 4.1 is hermetically closed with a housing lid 4.2. A tangential refrigerant inlet 13 is formed on the outer periphery of the motor housing 2.1. When viewed from the outside, the refrigerant compressor 1 according to the present invention is almost the same as the refrigerant compressor 1 shown in Figure 1a. Therefore, the same reference numerals are assigned to the repeated features. Section B is shown in Figure 3c.

[0032] Figure 3b is a schematic cross-sectional view of an exemplary embodiment of the refrigerant compressor 1 and is an axial longitudinal cross-sectional view through which the interior of the refrigerant compressor 1 can be seen. The inverter circuit board 7.1 including the motor electronic circuit is housed in a liquid-tight inverter housing 4.1 joined to the motor housing 2.1. A compressor housing 3.1 is joined to the opposite side of the motor housing 2.1, and a scroll compressor 5 is housed in the compressor housing 3.1. The scroll compressor 5 is connected to an electric motor 6 housed in the motor housing 2.1 via a drive shaft 6.1. An electric motor bearing 15 is provided in the motor housing 2.1, and the electric motor 6 is housed inside the motor housing 2.1 such that a narrow space is formed between the outer circumference of the electric motor 6 and the radially inner circumference of the motor housing 2.1.

[0033] During operation, this narrow space is filled with refrigerant, and a refrigerant flow path for the sucked-in refrigerant is formed along the narrow space. The refrigerant flow path 14 (see Figure 3c) passes along the end wall of the motor housing 2.1, and thus this housing wall is continuously exposed to refrigerant during operation. The housing wall 12 exposed to this refrigerant has a portion highlighted by diagonal lines and forms a fluid-tight partition between the motor housing 2.1 and the inverter housing 4.1 joined thereto. Therefore, the motor housing 2.1 and the inverter housing 4.1 share the refrigerant-exposed housing wall 12. Moldings 16, 17 for housing the heat-generating electronic components of the inverter circuit board 7.1 are provided on the side surface of the refrigerant-exposed housing wall 12 facing the inverter housing 4.1. The inverter circuit board 7.1 includes two DC link capacitors 9.1 and six electronic power switches 11.1 that rise perpendicularly from the plane of the inverter circuit board 7.1 and extend axially. The electronic power switches 11.1 are housed in the molding 17, and the dashed line 18 indicates the first component height of the electronic power switches 11.1 perpendicular to the plane of the inverter circuit board.

[0034] The first component height 18 substantially corresponds to the axial depth of the molding 17 in the refrigerant-exposed housing wall 12. Each of the one DC link capacitor 9.1 is accommodated in the molding 16 of the refrigerant-exposed housing wall 12. The dashed line 19 indicates a second component height corresponding to the component height of the two DC link capacitors 9.1 perpendicular to the surface of the inverter circuit board. The second component height 19 further substantially corresponds to the axial depth of the molding 16 in the refrigerant-exposed housing wall 12.

[0035] Figure 3c is a further schematic cross-sectional view of the refrigerant compressor according to the present invention. This is a cross-sectional view of the inverter housing 4.1 along the section B shown in Figure 3a. In this cross-sectional view, the inverter circuit board 7.1 housed in the inverter housing 4.1 can be seen. A part of the inverter circuit board 7.1 is located in the region of the refrigerant-exposed housing wall 12. The arrow 14 indicates the flow path of the refrigerant supplied to the motor housing 2.1 through the tangential refrigerant inlet 13. It can be seen that only a part of the inverter circuit board 7.1 is assigned to the region of the refrigerant-exposed housing wall 12 or the course of the refrigerant flow path to ensure heat transfer and heat dissipation. Therefore, a part of the inverter circuit board 7.1 is not located in the influence region of the refrigerant-exposed housing wall 12 and is located in the inverter accommodation part of the inverter housing 4.1 that protrudes beyond the outer periphery of the motor housing 2.1.

[0036] Figure 3d shows a schematic view of an exemplary embodiment of the inverter circuit board 7.1 as a plan view of the side facing only the refrigerant-exposed housing wall 12 excluding the surrounding inverter housing 4.1. On this side of the inverter circuit board 7.1, in addition to further electronic components, two DC link capacitors 9.1 and six electronic power switches 11.1 are arranged. The electronic power switch 11.1 is an IGBT or a MOSFET. In the region of the circular outer contour of the inverter circuit board 7.1, together with the six electronic power switches 11.1 arranged semi-circularly towards the end of the inverter circuit board 7.1, the two DC link capacitors 9.1 form the component arrangement of the heat-generating electronic components.

[0037] According to the present invention, the component arrangement of six electronic power switches 11.1 and two DC link capacitors 9.1 is arranged on the inverter circuit board 7.1 in the influence area of the refrigerant-exposed housing wall 12 when the inverter circuit board 7.1 is installed in the inverter housing 4.1. The six electronic power switches 11.1 and the two DC link capacitors 9.1 face the refrigerant-exposed housing wall 12. Different from the prior art embodiments of the refrigerant compressor 1 shown in FIGS. 1a to 1c, in the present invention, the heat-generating electronic components consisting of six electronic power switches 11.1 and two DC link capacitors 9.1 are arranged in a compact component arrangement with respect to the refrigerant-exposed housing wall 12 in order to achieve the dissipation of the generated heat by the refrigerant flow generated within the motor housing 2.1.

[0038] The six electronic power switches 11.1 extend vertically from the inverter circuit board 7.1, and the six electronic power switches 11.1 have equal component heights. Similarly, one DC link capacitor 9.1 also extends vertically from the inverter circuit board 7.1, and the component height of the DC link capacitor 9.1 protrudes vertically with respect to the inverter circuit board 7.1 and exceeds the component height of the electronic power switch 11.1. Therefore, the component arrangement of the six electronic power switches 11.1 and the two DC link capacitors 9.1 has a height profile with two different component heights 18 and 19 (see FIG. 3b). The arrangement of the DC link capacitor 9.1 and the electronic power switch 11.1 on the inverter circuit board 7.1 is directed towards the course of the refrigerant flow path 14 within the motor housing 2.1.

[0039] Figure 3e is a schematic plan view of the refrigerant-exposed housing wall 12 of the inverter housing 4.1 of the refrigerant compressor 1 according to the present invention. On this side, the refrigerant-exposed housing wall 12 has two moldings 16 provided for accommodating two DC link capacitors 9.1. The molding 16 is designed as a recess provided in the material of the refrigerant-exposed housing wall 12 and corresponds to the two DC link capacitors 9.1 arranged on the inverter circuit board 7.1 in terms of its arrangement and dimensions so that the DC link capacitors are accommodated in the molding 16 when the inverter circuit board 7.1 is attached to the inverter housing 4.1. The dimensions of the molding 16 are selected so that the contact surface between the molding 16 and the surface of the DC link capacitor 9.1 is as large as possible.

[0040] In any case, at least two sides of the two DC link capacitors 9.1 are in contact with the surface of the molding 16 that houses them. These are the end face and one side face of the cubic DC link capacitor 9.1 in each case. In order to cause thermal coupling, at least the rectangular top surface of the DC link capacitor 9.1 in the molding 16 is in contact with the refrigerant-exposed housing wall 12. Furthermore, it is also possible to provide at least one side of the DC link capacitor 9.1 in contact with the surface of the molding 16. Preferably, the molding 16 is dimensioned to receive the DC link capacitor 9.1 in a form-fitting manner. As a measure to improve thermal coupling, a thermal paste can be introduced between the DC link capacitor 9.1 and the molding 16 that houses them in each case.

[0041] Furthermore, on the refrigerant-exposed housing wall 12 of the inverter housing 4.1, three moldings 17 are provided for accommodating the electronic power switches 11.1. The moldings 17 are designed as recesses in the material of the refrigerant-exposed housing wall 12 of the inverter housing 4.1 so as to accommodate the electronic power switches 11.1 when the inverter circuit board 7.1 is attached to the inverter housing 4.1. Each molding 17 accommodates two electronic power switches 11.1. Thus, the height of the electronic power switches 11.1 perpendicular to the plane of the inverter circuit board 7.1 is substantially completely accommodated in the moldings 17. In order to promote heat coupling, a thermal paste can be introduced between the electronic power switches 11.1 and the moldings 17 that accommodate them. The moldings 17 are formed along the refrigerant flow path 14 formed in the motor housing 2.1 during operation.

[0042] The moldings 16 and 17 have no cross-connections and are formed at different depths in the refrigerant-exposed housing wall 12 due to the different component heights of the two DC link capacitors 9.1 and the six electronic power switches 11.1. Accordingly, the molding 16 that accommodates the DC link capacitor 9.1 is deeper than the moldings 17 for the six electronic power switches 11.1. A further design of the refrigerant-exposed housing wall 12 is configured such that, in the installed state, the planar inverter circuit board 7.1 faces in a direction perpendicular to the rotation axis of the electric motor 6 (see Fig. 3b).

[0043] Since the DC link capacitor 9.1 and the electronic power switches 11.1 are spatially separated by the moldings 16 and 17, the risk of mutual thermal influence is low. This advantageous effect is further enhanced by the different component heights 18 and 19. Furthermore, the contact between the sides of the DC link capacitor 9.1 and the electronic power switches 11.1 and the surfaces within the moldings 16 or 17 contributes to the improvement of heat dissipation because the heat transfer area is overall enlarged.

[0044] Figure 3f is a schematic plan view of the refrigerant-exposed housing wall 12 of the motor housing 2.1. Thus, the side surface of the refrigerant-exposed housing wall 12 facing the motor housing 2.1 is shown. The motor bearing 15 for accommodating the electric motor 6 is formed on this side.

[0045] According to the present invention, the DC link capacitor 9.1 (see FIG. 3d) is substantially arranged in the middle region of the motor housing 2.1 facing the motor bearing 15. Thereby, compared with the concept shown in FIGS. 1a to 1c in which the DC link capacitor 9 is located on the outer periphery of the motor housing 2.1, heat dissipation to the refrigerant is improved. Further, the electronic power switch 11.1 is arranged in a semi-circular shape on the inner wall of the compressor - suction space on an outer radius close to the radial direction. Therefore, its position is optimized in the region where the heat output to the refrigerant is maximized. Further, in terms of the distance between the DC link capacitor 9.1 and the electronic power switch 11.1, in order to reduce the inductive and capacitive interferences important for sufficient electromagnetic compatibility (EMC), the flow of the power - electronic load is optimized.

[0046] The refrigerant-exposed housing wall 12 can be designed as a separate housing component that guarantees a fluid-tight seal in the arrangement between the motor housing 2.1 and the inverter housing 4.1. For fixing, screw fastening to the motor housing 2.1 can be provided. For this purpose, corresponding screw holes can be provided in the refrigerant-exposed housing wall 12.

Explanation of reference numerals

[0047] 1 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 Rotating Shaft 7, 7.1 Inverter Circuit Board 8 Electrical Plug-in Terminal 9, 9.1 DC Link Capacitor 10 Dashed Line Region 11, 11.1 Electronic Power Switch 12 Refrigerant Exposure Housing Wall 13 Tangential Refrigerant Inlet 14 Arrow / Refrigerant Flow Path 15 Electric Motor Bearing 16, 17 Molding 18 Height of the First Component 19 Height of the Second Component

Claims

1. A drive unit (2); a compressor unit (3) coupled to the drive unit (2); The drive unit (2) comprises a motor housing (2.1) that accommodates an electric motor (6) having a rotatable shaft (6.1) through which a refrigerant can flow, The compressor unit (3) houses a scroll compressor (5) drivable by a shaft (6.1), The motor housing (2.1) has a housing wall (12) exposed to the drawn refrigerant and an inverter circuit board (7.1) joined thereto.

1. An electric refrigerant compressor comprising: a fluid-tight inverter housing (4.1); an inverter circuit board (7.1) having heat-generating electronic components, in particular at least one DC link capacitor (9.1) and a plurality of electronic power switches (11.1), and having at least two different component heights (18; 19) perpendicular to the inverter circuit board (7.1); the inverter circuit board (7.1) is housed in a plurality of moldings (16; 17) formed according to the component heights on a refrigerant-exposed housing wall (12) and is thermally coupled to the moldings.

2. 2. The electric refrigerant compressor of claim 1, wherein the electronic power switches (11.1) together have a first component height (18) and the at least one DC link capacitor (9.1) has a second component height (19) that protrudes perpendicularly to the inverter circuit board (7.1) beyond the first component height (18).

3. 3. An electric refrigerant compressor according to claim 2, characterized in that the mouldings (16; 17) are designed as recesses in the refrigerant-exposed housing wall (12).

4. 4. The electric refrigerant compressor according to claim 3, characterized in that the at least one DC link capacitor (9.1) and the plurality of electronic power switches (11.1) are each in contact with the refrigerant-exposed housing wall (12) on at least two sides of their surface.

5. 5. The electric refrigerant compressor according to claim 4, characterized in that the at least one DC link capacitor (9.1) and the plurality of electronic power switches (11.1) are conformably housed in a molding (16; 17), respectively.

6. 6. The electric refrigerant compressor according to claim 5, characterized in that the at least one DC link capacitor (9.1) is arranged in a central area of ​​the refrigerant-exposed housing wall (12) and the plurality of electronic power switches (11.1) are arranged in a semicircular or circular configuration around the at least one DC link capacitor (9.1).

7. 7. The electric refrigerant compressor according to claim 6, characterized in that a refrigerant flow path (14) is formed in the motor housing (2.1) along a refrigerant-exposed housing wall (12), and at least a plurality of electronic power switches (11.1) are arranged along the course of the refrigerant flow path (14) on the refrigerant-exposed housing wall (12).

8. 8. An electric refrigerant compressor according to claim 7, characterized in that the at least one DC link capacitor (9.1) is arranged on the inverter housing side of the refrigerant-exposed housing wall (12) in the region of a motor bearing (15) formed on the motor housing side of the refrigerant-exposed housing wall (12).

9. 9. An electric refrigerant compressor according to claim 8, characterized in that the motor housing (2.1) has a tangential refrigerant inlet (13).

10. 10. An electric refrigerant compressor according to claim 9, characterized in that the refrigerant-exposed housing wall (12) is designed as a separate housing cover of the motor housing (2.1).

11. 11. The electric refrigerant compressor according to claim 10, characterized in that for thermal coupling, a thermal paste is introduced between the heat-generating electronic components and the surface of the refrigerant-exposed housing wall (12).

12. Use of an electric refrigerant compressor according to any one of claims 1 to 11 in a refrigerant circuit of a vehicle.

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