WO2021066371A1

WO2021066371A1 - Device for driving a compressor and process for mounting the device

Info

Publication number: WO2021066371A1
Application number: PCT/KR2020/012778
Authority: WO
Inventors: Tim Münch; Bernadette Goebbels; Martin Westerhoff
Original assignee: Hanon Systems
Priority date: 2019-10-01
Filing date: 2020-09-22
Publication date: 2021-04-08
Also published as: DE102019126532B3

Abstract

The present invention relates to a device (3) for driving a compressor of a vapourous fluid, in particular an electric motor. The device (3) is produced with a housing (2) that comprises a cooling surface (16) and a power supply arrangement (5). The arrangement (5) exhibits at least one switching element (11, 11a), as well as a support element (13) with a perimeter wall (13c), and is arranged with the perimeter wall (13c) in contact with the housing (2) in the area of the cooling surface (16) on the housing (2). The perimeter wall (13c) of the support element (13) is produced such that it encloses a pass-through opening (13a). Here, the at least one switching element (11, 11a) is arranged such that it is in contact with the housing (2) inside the pass-through opening and in the area of the cooling surface (16) on the housing (2). The power supply arrangement (5) also exhibits at least one spring element (20) that is arranged on the support element (13) in order to press the at least one switching element (11, 11a) against the cooling surface (16) on the housing (2). The present invention also relates to a process for mounting the device (3).

Description

DEVICE FOR DRIVING A COMPRESSOR AND PROCESS FOR MOUNTING THE DEVICE

The present invention relates to a device, in particular an electric motor, for driving a compressor to compress a vapourous fluid, specifically a refrigerant. The device is produced with a housing that comprises a cooling surface and a power supply arrangement. The arrangement exhibits at least one switching element, as well as a support element with a perimeter wall, wherein the perimeter wall is in contact with the housing in the area of the housing's cooling surface. The compressor can be used in the refrigerant circuit of a motor vehicle air-conditioning system.

The present invention also relates to a process for mounting the device used to drive the compressor of a vapourous fluid.

Compressors known from the state of the art for mobile applications, in particular as air-conditioning systems in motor vehicles, that are used for conveying refrigerant through a refrigerant circuit, also known as refrigerant compressors, are often constructed as piston compressors with variable displacement or as scroll compressors irrespective of the refrigerant used. The compressors are driven either via a belt pulley or electrically here.

Alongside the electric motor for driving the respective compression mechanism, an electrically driven compressor also exhibits an electronic inverter for driving the electric motor. The inverter is used to convert the direct current (DC) supplied by a vehicle battery into alternating current (AC), which is then fed to the electric motor through electrical connections.

The inverter exhibits a PCB that contains switching elements, such as power transistors, which together form a compressor switching device. The power transistors of an inverter, also known as power switches, generate heat as a result of both switching and conduction losses that needs to be dissipated by the transistors in order to limit a maximum temperature of the power transistors. The dissipated heat, in particular of an electrically driven refrigerant compressor, should ideally be transferred to the refrigerant. Here, the power transistors are advantageously to be arranged on an outer side of the compressor housing such that they are in contact with the housing and can therefore conduct heat. The power transistors should be connected to the housing in the section of the housing with the lowest temperature, which is regularly located in the area of the intake port where the refrigerant flows into the compressor.

In the following, the section of the housing with the lowest temperature is also referred to as the cooling surface/area of the housing, specifically of the motor housing. The power transistors can be attached directly to the cooling surface in such a way that they conduct heat here. Each power transistor is to be thermally contacted with the cooling surface of the housing.

A good thermal contact can, for example, be produced using matched surface roughnesses. However, air pockets between the respective power transistor and the cooling surface of the housing must in particular be avoided here, as these can reduce heat transfer between the components.

In conventional units, thermal interface materials such as thermal paste or foils are used to guarantee good thermal contact and avoid the aforementioned air pockets. In addition to this, a certain constant pressure can be applied to the power transistors that consequently presses them against the cooling surface of the housing in order to reduce the respective thermal resistance between the cooling surface and the power transistor. Alongside establishing a good thermal contact, this pressure on the transistors also serves to attach the transistors or the inverter to the housing in a way that makes the connection vibration-resistant.

The notion of applying compressive force, which acts in the direction of the cooling surface of the housing, through a direct screw connection or a clamped connection, for example using spring elements, is known from the state of the art. When mounting the power transistors to the cooling surface of the housing, with potential inclusion of thermal interface materials between the power transistors and the cooling surface, the transistors are either screwed down or clamped to the housing, in particular to the cooling surface of the housing. After attaching the power transistors, a PCB is then for example attached. Here, the connections of the transistors can be arranged such that they are plated through the PCB and then soldered to the PCB.

In conventional designs, the power transistors are generally screwed down to the cooling surface of the housing. However, screwing the individual power transistors to the cooling surface of the housing leads to extremely high installation costs, not least since each screw needs to be accompanied by a washer for force distribution, as well as a ring of insulation. Use of the six power transistors that are typically arranged in the known inverters leads to a very large number of individual components. In addition to this, the power transistors are also connected to the PCB with soldering after being screwed down, meaning that access to the screws is covered. The screws are arranged below the PCB.

Here, each screw can be arranged such that is guided through a sleeve, in particular a metal sleeve, in order to allow the power transistors to be screwed down above the PCB. The screws are inserted through the PCB and arranged in such a way that the screw heads remain accessible even after fitting the PCB. However, the metal sleeves also generate additional costs, including greater installation costs, particularly when the sleeves are arranged such that they are freestanding rather than being held in place by an additional retaining element.

Use of a plastic frame to press the power transistors against the cooling surface of the housing is also known. Here, the sleeves are arranged such that their end faces are in contact with a screw, in particular the screw head, on one side and with the plastic frame on the other. The contact pressure is thereby transferred from the screws to the sleeves and, via the plastic frame, to the power transistors, which are pressed against the cooling surface of the housing. However, depending on time and temperature, the force characteristic inside the plastic frame can cause the plastic to deform, which in turn reduces the force acting on the power transistors and means that the minimum contact pressure required for pressing the power transistors against the cooling surface of the housing is potentially no longer guaranteed. The only way to counteract this effect is by using cost-intensive special plastics.

The contact pressure is directly related to the thermal output that is transferred from the power transistor to the cooling surface of the housing. If the contact pressure is reduced too much, this can lead to one or more power transistors overheating and thereby to a malfunction of the electronics and consequently also the compressor.

The object of the invention lies in provision and improvement of an inverter for a device used to drive an electrically driven compressor of a vapourous fluid, in particular an electric motor, that can also be fitted easily and therefore quickly. The focus here is on dissipating as much heat as possible from the power transistors through optimum heat transfer, in particular transferring the heat to the fluid that is to be compressed in the compressor. The device should employ a basic design and therefore be easy to produce in order to minimise manufacturing costs. The arrangement should facilitate secure operation of the device and a maximum service life.

The task is resolved by the subject matter with the characteristics of the independent patent claims. Further embodiments are provided in the dependent patent claims.

The object is resolved by a device according to the invention for driving a compressor of a vapourous fluid, in particular an electric motor. The device is produced with a housing that comprises a cooling surface and a power supply arrangement. The arrangement exhibits at least one switching element, as well as a support element with a perimeter wall. The power supply arrangement, preferably produced as a three-phase inverter, is in contact with the housing with the perimeter wall in the area of the housing's cooling surface.

According to the design of the invention, the perimeter wall of the support element, itself advantageously produced from a metal, is produced such that it encloses a pass-through opening. Here, the at least one switching element is arranged such that it is positioned inside the pass-through opening of the support element and is in contact with the housing in the area of the housing's cooling surface. The power supply arrangement exhibits at least one spring element on the support element for pressing the at least one switching element against the cooling surface of the housing. The switching element is preferably produced as a power transistor.

The support element and the housing can alternatively be produced either as separate components or as a one-piece component.

As per a further embodiment of the invention, the support element exhibits brackets for attaching and holding the at least one spring element. Here, the brackets are advantageously produced as raised sections that stretch from the perimeter wall and into the pass-through opening, each in particular aligned orthogonally to the perimeter wall.

As per a preferred embodiment of the invention, the spring element is produced in the form of a ring, which is in particular fully enclosed around its perimeter. Here, the ring, at least in its original form, is understood to be a cylindrical, flat component, whose planar extension is several times greater than its vertical extension to the aforementioned plane, in particular the thickness or height of the cylinder. The component, which is flat at least in its initial form, exhibits a recess in the form of a opening that passes through the plane and can be fully enclosed around its perimeter. The edge formed in this way is significantly narrower relative to the central recess. The ring and the recess can each exhibit freely designed outer shapes here and are definitely not restricted to a specific shape, such as circular cylinder, in particular a hollow circular cylinder. A rectangular shape would, for example, also be possible, in which three switching elements are arranged adjacently to one another in a first direction and adjacently to one another in two rows in a second direction. The shape of the spring element is consequently matched to the arrangement of the switching elements.

The ring can also be formed such that it projects out of the plane and includes additional recesses or shapes.

The spring element preferably exhibits at least two sections, each with a tab and at least one section with at least one strip element. Here, the sections produced with the tab are each arranged adjacently to a section with the strip element.

An advantage of the invention lies in the fact that each tab of the spring element is produced with a pass-through opening on one free end for attaching the spring element to the support element and is connected to the ring of the spring element on an end that is produced distally to the free end.

Here, the tabs can be produced such that they project out of a plane of the ring and are arranged in the area of the pass-through openings such that they are aligned on a common plane that runs parallel and at a distance from the plane of the ring, meaning that the cross-sections of the pass-through openings are consequently aligned on a common plane. On the end with the pass-through opening, the tabs are preferably bent over at a specific angle, for example in the range from 60° to 90°, essentially a right angle, in particular outwards.

As per an advantageous embodiment of the invention, one free end of the at least one strip element projects out of a plane of the ring and is connected to the ring of the spring element on an end that is produced distally to the free end. Here, the tabs are preferably each aligned such that a first side projects out of a plane of the ring and the at least one strip element projects out of the plane of the ring towards a second side on a free end. The free end of the at least one strip element and the tabs with the pass-through openings consequently project out of the plane of the ring in the opposite direction, in particular each projecting orthogonally. The strip element can be bent over at a specific angle, for example in the range from 60° to 90°.

The tabs are each preferably arranged on an outer circumference of the ring, while the at least one strip element is arranged on the outer circumference or on an inner circumference of the ring.

At least one first strip element and/or at least one second strip element can be produced inside the at least one section of the spring element with strip element.

In the case of an embodiment of the arrangement for power supply with at least two switching elements, a second strip element of the spring element can be assigned to two switching elements that are arranged adjacently to one another. The switching elements can be arranged in pairs here, wherein at least two second strip elements are advantageously produced inside the at least one section of the spring element with strip element. In addition to this, a first strip element is preferably arranged between the two switching elements.

As per a further embodiment of the invention, the spring element is produced in a star shape with three outer, convex and rounded off corners, as well as three inner, concave and rounded off corners that are arranged within a common plane. Here, a section with a tab or a section with the at least one strip element is, in particular, arranged between each convex corner and a concave corner that is itself arranged adjacent to this in such a way that the sections with a tab and the sections with at least one strip element wrap around the ring of the spring element in alternation.

Another advantage of the invention lies in the fact that the at least one spring element is produced from a elastically deformable material, in particular a metal.

The power supply arrangement also preferably exhibits a cover element that encloses a volume in conjunction with the support element and the cooling surface of the housing. Here, the at least one spring element and the at least one switching element are, in particular, arranged inside the volume enclosed by the support element, the cover element and the housing.

According to another advantageous embodiment of the invention, the power supply arrangement exhibits at least one PCB that is arranged on and attached to the support element. Here, the at least one PCB is preferably arranged inside the volume enclosed by the support element, the cover element and the housing, as well as specifically attached to the brackets for attaching the at least one spring element.

The at least one switching element is preferably arranged on and connected to the PCB, in particular soldered to the PCB. Here, the spring element is advantageously arranged between the PCB and the at least one switching element.

The spring element is preferably attached to the support element using attachment elements, in particular at least one screw connection, also together with the PCB. Here, the attachment elements can be arranged such that they are guided through the pass-through openings produced in the spring element, as well as the openings produced in the PCB, and into the brackets of the support element, wherein the shape and arrangement of the pass-through openings provided in the spring element correspond to the openings produced in the PCB. The spring element is preferably arranged between the support element and the PCB. The spring element is advantageously supported against the brackets of the support element.

According to another preferred embodiment of the invention, one side of the at least one spring element is arranged such that it is in contact with the switching element that is produced on the opposite side to the side of the switching element that faces the cooling surface, meaning that the switching element is arranged such that it is pressed by the spring element in the direction of the cooling surface on the housing. Consequently, the spring element is in contact with the switching element on a side of the switching element that faces the PCB.

As per a further embodiment of the invention, the perimeter wall of the support element is essentially aligned orthogonally to the cooling surface of the housing and is in contact with the housing on a first end face in the area of the cooling surface or a flange, wherein the flange is arranged on a different plane to the cooling surface. The cover element of the power supply arrangement is advantageously produced such that it can be arranged on a second end face of the perimeter wall of the support element that is aligned distally to the first end face and thereby seals the arrangement. Here, one sealing element can be arranged between the first end face of the support element's perimeter wall and the housing, as well as between the second end face of the support element's perimeter wall and the cover element. In the alternative embodiment of the support element and the housing as a one-piece component, the sealing element to be arranged between the first end face of the support element's perimeter wall and the housing is omitted.

The task is also resolved by an inventive method for mounting the device used to drive a compressor of a vapourous fluid, in particular an electric motor. This method exhibits the following steps:

- Arrangement of a spring element on a PCB in such a way that pass-through openings produced in the spring element line up with corresponding openings on the PCB

- Connection of at least one switching element to the PCB, wherein the spring element is arranged between the PCB and the switching element such that it applies a pressure on the switching element in a direction away from the PCB, as well as

- Arrangement and attachment of the PCB with the at least one switching element and the spring element to the support element, meaning that the at least one switching element arranged in a pass-through opening of the support element is in contact with a cooling surface of the housing

As per a further embodiment of the invention, a power supply arrangement is premounted to the support element as a modular component. The arrangement with the support element is then arranged and attached to the housing of the device in such a way that the at least one switching element arranged in the pass-through opening of the support element is in contact with the cooling surface of the housing.

An advantage of the invention lies in the fact that connections of the switching element are arranged such that they are plated through the PCB and then connected to the PCB, in particular soldered. Here, the modularity in particular allows the PCB to be soldered to the switching elements without the presence of the housing.

To establish the connections of the switching element to the PCB, particularly with the power supply arrangement as a modular component, the switching element is preferably moved into a mounting position by a mounting device in a direction running towards the PCB and against a compressive force that is applied by the spring element. Here, the spring element is advantageously elastically deformed. The mounting device is then removed after establishing the connections of the switching element to the PCB.

The switching elements are held in a specific position during assembly using additional strip elements that are produced on the spring element.

As per a preferred embodiment of the invention, the surface of the switching element facing the housing is pressed against the cooling surface of the housing due to the compressive force generated by the spring element.

When the device is mounted, the spring element is in contact with the switching element in an elastically deformed way. As a result of the pressure applied by the elastic deformation of the spring element on the switching element, the switching element is pressed against the cooling surface of the housing in such a way that optimum heat transfer from the switching element to the cooling surface is guaranteed. Here, at least one thermal interface material, such as a thermal paste or foil, is preferably arranged between the switching element and the cooling surface of the housing.

The power supply arrangement can, for example, be sealed off using a cover element before, during or after arranging and attaching the arrangement to the housing of the device.

The advantageous embodiment of the invention allows the device to be used to drive a compressor, in particular an electric motor, for compressing a vapourous fluid for a compressor of a refrigerant in a refrigerant circuit of a motor vehicle air-conditioning system.

Above all, use of the modular arrangement, specifically of an inverter for an electric motor of a refrigerant compressor, in connection with use of the spring force of the metallic spring element, allows the thermal influence, in particular of the switching elements / power transistors, to be significantly reduced over devices known from the state of the art.

As a result of the direct thermal contact between the power transistors and the cooling surface of the housing, a thermal resistance is reduced in comparison with conventional structures of an inverter, which leads to increased cooling performance of the power transistors. The thermal contact, and thereby also the heat transfer process, are both improved with the arrangement of the at least one thermal interface material between the power transistor and the cooling surface of the housing.

The device according to the invention for driving a compressor of a vapourous fluid and the process for mounting the device collectively exhibit various other advantages:

- Optimum and reliable heat transfer, in particular to the fluid that is to be compressed in the compressor, with the maximum amount of heat that can be dissipated from the power transistors

- A simple design of the arrangement, also thanks to a small number of individual components, meaning that it can be produced easily with minimum assembly and manufacturing costs

- Simple and time-saving assembly

- The simple design of the spring element as a punched and bent element reduces the likelihood of complex faults occurring, while at the same time increasing the quality of the device

- The spring element delivers the requisite force for pressing the power transistors against the cooling surface of the housing throughout the entire service life at various temperatures, and thereby irrespective not only of the temperature but also of moisture and vibrations, with good reproducibility, thereby leading to

- Reliable and lifelong thermal connection of the power transistors to the housing

urther details, features and benefits of embodiments of the invention result from the following description of embodiment examples with reference to the accompanying drawings. These display the following:

Fig. 1: A sectional view of an electrically driven compressor with a device, in particular an electric motor, for driving a compression mechanism and an arrangement of an inverter.

Fig. 2a: A perspective view of a pre-mounted PCB with power transistors inserted into the PCB and soldered to the PCB, as well as a connected spring element.

Figs. 2b & 2c: A perspective view of the spring element with pass-through openings for attaching to a support element, as well as strip elements for contacting with the power transistors.

Fig. 2d: A perspective view of a support element of the inverter arrangement with a pass-through opening and raised sections for attaching the spring element.

Fig. 2e: A perspective view of the arrangement of the modular inverter with the support element and the premounted PCB from Fig. 2a.

Fig. 2f: A lateral sectional view of the arrangement of the modular inverter when attached to the housing of the compressor.

Fig. 1 shows a sectional view of an electrically driven compressor 1 with an electric motor 3 arranged in a housing 2 as a device for driving a compression mechanism 4 and an arrangement 5 of an inverter. The electric motor 3 is powered via a switching device 6 of the arrangement 5.

The electric motor 3 exhibits a stator 7 with an essentially hollow cylinder-shaped stator core and coils wound on the stator core, as well as a rotor 8 arranged inside the stator 7. The rotor 8 is set into rotation when electrical energy is supplied to the coils of the stator 7 via a connection arrangement 9. The connection arrangement 9 is produced on an end face of the stator 7 and exhibits a large number of electrical connections.

The rotor 8 is arranged coaxially inside the stator 7 and in such a way that it can be rotated around a rotary axis. A drive shaft 10 can be produced integrally with the rotor 8 or as a separate element.

The electric motor 3 and the compression mechanism 4, produced in the form of a scroll compressor with one fixed and one orbiting scroll, are arranged inside a volume enclosed by the housing 2. Here, the housing 2 comprises a first housing element for mounting the electric motor 3 and a second housing element for mounting the compression mechanism 4, preferably produced from a metal, in particular an aluminium.

The orbiting scroll of the compression mechanism 4, in which the vapourous fluid, specifically a refrigerant, is compressed, is driven via the drive shaft 10 that is connected to the rotor 8 of the electric motor 3. As per an embodiment not shown, the compression mechanism can, for example, also be produced with a wobble plate.

The switching device 6 for controlling operation of the electric motor 3 exhibits a PCB 12 that is produced with various switching elements 11. Various control circuits and components are premounted on the PCB 12 with electrical connections and powered by an external power source.

The PCB 12 with the switching elements 11 is arranged inside a support element 13 of the inverter arrangement 5 and fixed in the support element 13. The arrangement 5 is sealed off by a cover element 14.

Fig. 2a shows a perspective view of a pre-mounted PCB 12 with power transistors inserted into and soldered to the PCB 12, as well as a connected spring element 20. The six power transistors 11a of the inverter, preferably produced for three-phase operation and also referred to as a three-phase inverter, are each arranged in pairs on the PCB 12. Alternatively, the power transistors 11a can also be aligned in an arrangement that differs from the described arrangement in pairs.

The spring element 20, which is produced as a sealed unit on all sides, is arranged between the PCB 12 and the power transistors 11a. The direction in which the force generated by the spring element 20 is applied is essentially aligned orthogonally to the plane of the surface of the PCB 12 on which the power transistors 11a are arranged. The force then acts in a direction that runs from the PCB 12 to the power transistor 11a.

The spring element 20 is attached to the support element 13 (not shown) together with the PCB 12 using attachment elements (also not shown). When mounting the inverter arrangement 5, the attachment elements are guided through pass-through openings 21 produced in the spring element 20.

Depending on the sequence of installation steps, the PCB 12 can already be connected to the spring element 20 and the support element 13, in particular screwed down, when mounting the arrangement 5. The pass-through openings 21 provided in the spring element 20 correspond to the openings produced in the PCB 12 in terms of both shape and arrangement.

To simplify the process for mounting the power transistors 11a, the spring element exhibits first strip elements 22a, as well as second strip elements (not visible). Here, the first strip elements 22a are used to attach the power transistors 11a during the process of mounting the arrangement 5. The second strip elements are each arranged between the power transistors 11a, which are themselves arranged in pairs and directly adjacent to one another, in particular in order to secure a minimum spacing between the power transistors 11a.

Figs. 2b and 2c each show a perspective view of the spring element 20 with the pass-through openings 21 for attachment to the support element 13 (not shown), as well as with the first strip elements 22a and the second strip elements 22b for contacting with the power transistors 11a (also not shown).

The spring element 20 is produced as a punched and bent element from an elastic metal sheet that is punched or cut out and then bent over during manufacture. Here, the spring element 20 preferably exhibits the shape of a fully enclosed ring, in particular a disk-shaped ring. The ring is produced in a star shape with three outer corners that are aligned on a common plane. Both the outer convex corners, also referred to as tips, and the three inner concave corners are each rounded off, in particular in order to guarantee high strength of the spring element 20.

Sections of the ring with either a tab or

strip elements

22a, 22b are provided between each convex corner and a concave corner arranged adjacent to this, each of which project at an outer edge of the ring as first strip elements 22a and at an inner edge of the ring as second strip elements 22b. Accordingly, a tab, a convex or concave corner and two first strip elements 22a are each arranged one after the other around the outer edge of the ring of the spring element 20 in such a way that a section with first strip elements 22a, produced in pairs, is assigned to each section with a tab. One corner of the star-shaped ring is produced such that it connects the sections.

Here, each tab exhibits a pass-through opening 21 on a free end for attaching the spring element 20. The tab is connected to the ring of the spring element 20 on the end that is produced distally to the free end. When bending over the spring element 20, the tabs or sections of the ring produced with the tab are deformed in such a way that the cross-sections of the pass-through openings 21 are aligned on a common plane that runs parallel and at a distance from the plane of the ring. The tabs are preferably bent outwards at a right angle on the free end with the pass-through opening 21.

The first strip elements 22a, each produced in pairs, and the second strip element 22b of a section of the ring or of one side of the star-shaped ring are each bent over on a free end vertically relative to the plane of the ring. The

strip elements

22a, 22b are connected to the ring of the spring element 20 on the end that is produced distally to the free end. When bending over the spring element 20, the

strip elements

22a, 22b are consequently deformed in such a way that the free ends of the

strip elements

22a, 22b project out of the plane of the ring orthogonally in opposing directions with regard to the tabs with the pass-through openings 21.

As shown in Fig. 2a, when the arrangement 5 is fitted, the spring element 20 is firstly in direct contact with the PCB 12 in the area of the free ends of the tabs with the pass-through openings 21. Secondly, the free ends of the first strip elements 22a are each arranged on one side of a power transistor 11a, while the second strip elements 22b are each arranged between power transistors 11a, themselves arranged adjacently to one another, such that they are in contact with the power transistor 11a on one side of the power transistor 11a. Each power transistor 11a is pressed by the spring element 20 in the direction away from the PCB 12. The

strip elements

22a, 22b are each in contact with the power transistor 11a on a narrow side of the power transistor 11a. Here, a first strip element 22a of the spring element 20 is assigned to each power transistor 11a, while a common second strip element 22b is assigned to the two power transistors 11a that are arranged adjacently to one another. The second strip element 22b is arranged between the two adjacent power transistors 11a here.

When the compressor 1 is assembled, the power transistors 11a are in contact with the cooling surface on the housing of the compressor 1 on a side facing away from the PCB 12. The spring element 20 thereby presses the power transistors 11a against the cooling surface of the housing.

The spring element 20 is produced in such a way that the spring force generated, which corresponds to the force pressing the power transistors 11a against the cooling surface of the housing, does not drop below a specific value over time or as a result of the environmental conditions in place within the volume enclosed by the support element 13 (not shown). The necessary force is provided with limited deflection. Here, the spring element 20 exhibits a very low decrease in spring force over time, meaning that the spring element 20 exhibits sufficient reliability throughout its entire service life, regardless of the temperature, humidity and vibrations present in its environment.

The spring element can also exhibit different forms and embodiments, for example based on the structure and design of the PCB 12, of the housing and of the support element.

Fig. 2d provides a perspective view of the support element 13 of the inverter arrangement 5 with a pass-through opening 13a and raised sections 13b for attaching the spring element 20, while Fig. 2e provides a perspective view of the arrangement 5 of the modular inverter with the support element 13 and the premounted PCB 12 from Fig. 2a. Fig. 2f provides a lateral sectional view of the arrangement 5 of the modular inverter from Fig. 2e when fitted to the housing 2 of the compressor.

When the compressor is assembled, the support element 13, which is provided as a mounting element and housing element, is arranged and aligned with the pass-through opening 13a facing the cooling surface 16 of the housing 2 of the compressor 1 or of the electric motor 3 of the compressor 1. The entire perimeter wall 13c of the support element 13, itself preferably produced from a metal, is in contact with the housing 2 around the entire circumference of the pass-through opening 13a here. The perimeter wall 13c is essentially aligned orthogonally to a plane produced by the pass-through opening 13a and is arranged such that it is in contact with the housing 2 on a first end face. On a second end face of the perimeter wall 13c that is aligned distally to the first end face, the arrangement 5 can be sealed off using the cover element 14 shown in Fig. 1, which is in contact with the support element 13 via the second end face of the perimeter wall 13c when the arrangement 5 is fitted.

According to an alternative embodiment that is not shown, the housing 2 and the support element 13 are produced as a one-piece component.

The PCB 12, arranged inside the volume enclosed by the support element 13 with the cover element 14, is firmly attached to the support element 13 using both first attachment elements 26 and second attachment elements 27. Here, the first attachment elements 26 are guided into first mounting holes 23 that are produced in the support element 13, while the second attachment elements 27 are guided into second mounting holes 24 that are produced in the support element 13.

The first mounting holes 23 are each arranged inside a raised section 13b, in particular on a free end of the raised section 13b that projects into the pass-through opening 13a. The raised sections 13b are each attached to the perimeter wall 13c of the support element 13 on the end that is produced distally to the free end.

The connections, each comprising a first attachment element 26 and first mounting holes 23, are also used for attaching the spring element 20 to the support element 13. Here, the spring element 20 is arranged between the PCB 12 and the support element 13. The spring element 20 rests against the raised sections 13c and thereby also against the support element 13, meaning that none of the force generated by spring element 20 is transferred to the PCB 12.

The first attachment elements 26 are preferably produced as screw connections with the first mounting holes 23.The second attachment elements 27 can also be produced as screw connections with the second mounting holes 19.

Figs. 2e and 2f in particular show the support element 13 with the PCB 12 already fitted and the power transistors 11a from the arrangement 5 both inserted into the PCB 12 and soldered to the PCB 12. The power transistors 11a are arranged inside through the pass-through opening 13a of the support element 13, wherein the connections of the power transistors 11a, which are bent over 90°, are arranged such that they are inserted through or plated through the PCB 12 and soldered in place. The spring element 20 is arranged between the PCB 12 and the power transistors 11a in such a way that it applies a pressure on the power transistors 11a.

The surfaces of the power transistors 11a that face away from the PCB 12, preferably metallic and also referred to as heat transfer surfaces, in particular surfaces for heat dissipation, are aligned such that they face the cooling surface 16 on the housing 2 of the compressor 1. The compressive force generated by the spring element 20 is applied vertically relative to the plane of the pass-through opening 13a or the cooling surface 16 on the housing 2.

A refrigerant flows over the back section of the cooling surface 16 on the housing 2, i.e. on the opposite side to the cooling surface 16. Here, the refrigerant flows inside the volume 28 enclosed by the housing 2, meaning that the heat dissipated from the power transistors 11a is transferred directly to the refrigerant.

During assembly of the compressor 1, in particular of the inverter arrangement 5, the spring element 20 is positioned on the PCB 12 in such a way that the pass-through openings 21 line up with the corresponding openings on the PCB 12.

The power transistors 11a, for example insulated-gate bipolar transistors (IGBT), are then mechanically connected to the PCB 12 with connections that are guided through the PCB 12. In order to connect, in particular to solder, the connections of the power transistors 11a to the PCB 12, a mounting device is used to move the power transistors 11a in a direction that runs towards the PCB 12, thereby against the direction in which the force of the spring element 20 is applied, and into a mounting position. The spring element 20 is elastically deformed here. In addition to this, the spring element 20 is, for example, bent over the

strip elements

22a, 22b, in particular to guide the power transistors 11a into specific positions.

After connecting the power transistors 11a to the PCB 12 and removing the mounting device, the power transistors 11a are pretensioned against the PCB 12 in the direction facing away from the PCB 12.

The PCB 12, with the power transistors 11a arranged on it and pretensioned via the spring element 20, is then attached to the support element 13 using the first attachment elements 26 and the second attachment elements 27. The first attachment elements 26 are used to transfer the spring force, generated by the spring element 20 and applied to the power transistors 11a, directly to the retaining elements of the support element 13, produced as raised sections 13b, meaning that the PCB 12 is not subjected to any bending force.

According to an alternative assembly approach, the power transistors 11a are arranged in predetermined positions on a mounting plate, for example using a mounting aid such as a template or an assembly robot, before the spring element 20 is then placed onto the power transistors 11a.

In the next assembly step, the PCB 12 is set down onto the spring element 20, while at the same time the connections of the power transistors 11a are inserted through the PCB 12. Once this is complete, the PCB 12 is attached, together with the spring element 20 arranged inbetween, to the support element 13 via attachment elements. The power transistors 11a are then finally soldered to the PCB 12.

In the final step of mounting the arrangement 5 to the housing 2 of the compressor 1, third attachment elements (not shown) are inserted through the cover element 14, through a sealing element that is arranged between the cover element 14 and the support element 13, as well as between the support element 13 and the housing 2, and into mounting holes provided in the housing 2, where they are then preferably screwed down. The third attachment elements are inserted through third mounting holes 25 on the support element 13.

The arrangement 5 is then fixed to the cover element 14 on the housing 2. Here, the power transistors 11a are in contact with the areas on the cooling surface 16 of the housing 2 that are aligned such that they face away from the PCB 12 and are pressed against the cooling surface 16 of the housing 2, in particular for heat dissipation, as a result of the compressive force generated by the spring element 20. After completing the process for mounting the arrangement 5 to the housing 2 of the compressor 1, the power transistors 11a are in the correct position for the intended use. The connections of the power transistors 11a to the PCB 12, in particular the solder points and the PCB 12, are free of any mechanical tension.

According to an alternative process, the support element 13 is attached to the housing 2 before mounting the PCB 12 with the spring element 20 and power transistors 11a that are soldered to the PCB 12. Following this, the PCB 12 is then attached to the support element 13 with the spring element 20 and the power transistors 11a that are soldered to the PCB 12. When using a one-piece design for the housing 2 and support element 13, the process of arranging the support element 13 on the housing 2 is omitted.

As a way of also minimising the thermal resistance between the power transistors 11a and the cooling surface 16 on the housing 2, a thermal interface material, for example a thermal paste or foil, is also used in addition to the pressure applied between the power transistors 11a and the cooling surface 16 on the housing 2. The interface material is applied between the heat transfer surface of the power transistor 11a and the cooling surface 16 on the housing 2 in order to guarantee a good thermal contact.

The spring element 20 exhibits a defined stiffness. When mounting the arrangement 5 to the housing 2, a force that essentially acts in the axial direction of the device 3, in particular a spring force, is produced between the spring element 20 and thereby each power transistor 11a, as well as the cooling surface 16 on the housing 2, such that each power transistor 11a is pressed in the direction of the housing 2 as a result of the elastic properties of the spring element 20. Here, the force acts on the power transistor 11a when the power transistor 11a is placed in contact with the housing 2 and the spring element 20 is elastically deformed. Once the procedure for mounting the arrangement 5 to the housing 2 is complete, a preload is generated through the elastic deformation of the spring element 20 which clamps the power transistors 11a in place.

The spring force of the spring element 20 is, in particular, designed such that it delivers sufficient force, even with a relatively small deflection, so that only a specific value of the compressive force is applied to the power transistors 11a when the arrangement 5 has not been mounted to the compressor 1, but that, when the arrangement 5 is fitted to the compressor 1, a sufficient compressive force is generated in order to press the power transistors 11a against the cooling surface 16 of the housing 2 with a predetermined, sufficient compressive force. The spring constant of the spring element 20 is consequently specified in such a way that firstly an excessive deflection of the power transistors 11a from a stop position is avoided when the compressor 1 is not fitted and secondly that application of a sufficient compressive force to the power transistors 11a and thereby the cooling surface 16 of the housing 2 is guaranteed when the compressor 1 is fitted.

With its modular design, the arrangement 5 represents a coherent unit, comprising the listed components, that can then be connected directly to the compressor, in particular the housing 2 of the compressor 1. Here, the support element 13, which is aligned with the cooling surface 16 of the housing 2 with its pass-through opening 13a and the power transistors 11a arranged inside it, is pre-assembled with the spring element 20 attached to the support element 13, preferably with screws, and with the power transistors 11a that are soldered to the PCB 12.

Thanks to it modular design, the arrangement 5 can be removed from the compressor 1 and then remounted to the housing 2 without any restrictions of the cooling function of the power transistors 11a that results from the spring element 20.

List of reference numbers

1 Compressor

2 Housing

3 Device, electric motor

4 Compression mechanism

5 Arrangement

6 Switching device

7 Stator

8 Rotor

9 Connection arrangement

10 Drive shaft

11 Switching element

11a Switching element, power transistor

12 PCB

13 Support element

13a Pass-through opening, support element 13

13b Raised section

13c Perimeter wall, support element, 13

14 Cover element

16 Cooling surface, housing 2

20 Spring element

21 Pass-through opening, spring element 20

22a First strip element, spring element 20

22b Second strip element, spring element 20

23 First mounting hole for attachment element, spring element 20

24 Second mounting hole for attachment element, PCB 12

25 Third mounting hole, third attachment element 21

26 First attachment element, spring element 20 and PCB 12

27 Second attachment element, PCB 12

28 Volume of refrigerant

Claims

Device (3) for driving a compressor of a vapourous fluid with a housing (2) with a cooling surface (16) and a power supply arrangement (5), wherein the arrangement (5) exhibits at least one switching element (11, 11a), as well as a support element (13) with a perimeter wall (13c) and is arranged such that the perimeter wall (13c) is in contact with the housing (2) in the area of the cooling surface (16) of the housing (2), characterised in that the perimeter wall (13c) of the support element (13) is produced such that it surrounds a pass-through opening (13a) and the at least one switching element (11, 11a) is arranged inside the pass-through opening (13a), as well as in contact with the housing (2) in the area of the cooling surface (16) of the housing (2), wherein the arrangement (5) exhibits at least one spring element (20), arranged on the support element (13), in order to press the at least one switching element (11, 11a) against the cooling surface (16).
Device (3) according to claim 1, characterised in that the support element (13) exhibits brackets for attaching the at least one spring element (20).
Device (3) according to claim 2, characterised in that the brackets take the form of raised sections (13b) that are produced such that they stretch from the perimeter wall (13c) and into the pass-through opening (13a).
Device (3) according to one of the claims 1 to 3, characterised in that the spring element (20) is produced in the form of a ring.
Device (3) according to claim 4, characterised in that the spring element (20) exhibits at least two sections, each of which exhibits a loop, and at least one section with at least one strip element (22a, 22b), wherein the sections with the loop are each located adjacent to a section with the strip element (22a, 22b).
Device (3) according to claim 5, characterised in that each loop of the spring element (20) is produced with a pass-through opening (21) on one free end for attaching the spring element (20) to the support element (13) and connected to the ring of the spring element (20) on an end that is produced distally to the free end.
Device (3) according to claim 6, characterised in that the loops are each produced such that they project out of a plane of the ring and are both aligned and arranged on a common plane, in the area of the pass-through openings (21), that runs parallel to and at a distance from the plane of the ring.
Device (3) according to one of the claims 5 to 7, characterised in that the at least one strip element (22a, 22b) is produced such that it projects out of a plane of the ring on one free end and is connected to the ring of the spring element (20) on an end that is produced distally from the free end.
Device (3) according to one of the claims 5 to 8, characterised in that each of the loops is produced and aligned such that the first side projects out of a plane of the ring and the at least one strip element (22a, 22b) is produced and aligned such that it projects out of the plane of the ring on a free end to a second side.
Device (3) according to one of the claims 5 to 9, characterised in that at least one first strip element (22a) and/or at least one second strip element (22b) are produced inside the at least one section of the spring element (20) with the strip element (22a, 22b).
Device (3) according to claim 10, characterised in that, when producing at least two switching elements (11, 11a), a second strip element (22b) of the spring element (20) is assigned to two switching elements (11, 11a) that are adjacent to one another.
Device (3) according to one of the claims 4 to 11, characterised in that the spring element (20) is produced in a star shape with three outer, convex and rounded off corners, as well as three inner, concave and rounded off corners that are arranged on a common plane.
Device (3) according to claim 12, characterised in that between each convex corner and a concave corner arranged adjacent to this a section with a loop or a section with the at least one strip element (22a, 22b) is arranged such that the sections with a loop and the sections with at least one strip element (22a, 22b) encircle the ring of the spring element (20) in alternation.
Device (3) according to one of the claims 1 to 13, characterised in that the at least one spring element (20) is produced from an elastically deformable material.
Device (3) according to one of the claims 2 to 14, characterised in that the arrangement (5) is produced with at least one PCB (12) arranged on the support element (13).
Device (3) according to claim 15, characterised in that the at least one PCB (12) is arranged on the brackets for attaching the at least one spring element (20).
Device (3) according to claim 15 or 16, characterised in that the at least one switching element (11, 11a) is arranged on the PCB (12).
Device (3) according to one of the claims 15 to 17, characterised in that the at least one spring element (20) is arranged between the PCB (12) and the at least one switching element (11, 11a).
Device (3) according to one of the claims 15 to 18, characterised in that the spring element (20) is arranged such that it is attached together with the PCB (12) to the support element (13) using attachment elements, wherein the attachment elements are routed through pass-through openings (21) produced in the spring element (20), as well as openings produced in the PCB (12) and introduced into the brackets of the support element (13).
Device (3) according to one of the claims 5 to 19, characterised in that the at least one spring element (20) is arranged such that it is contact with one side of a switching element (11, 11a), itself produced on the opposite side of the switching element (11, 11a) to the side aligned with the cooling surface (16), meaning that the switching element (11, 11a) is arranged such that it is pressed in the direction of the cooling surface (16) of the housing (2) by the spring element (20).
Process for mounting the device (3) to drive a compressor of a vaporous fluid according to one of the claims 1 to 20, exhibiting the following steps:

- Arrangement of a spring element (20) in such a way on a PCB (12) that pass-through openings (21) produced in the spring element (20) line up with the corresponding openings on the PCB (12),

- Connection of at least one switching element (11, 11a) to the PCB (12), wherein the spring element (20) between the PCB (12) and the switching element (11, 11a) is arranged such that it exerts a pressure on the switching element (11, 11a) in a direction moving away from the PCB (12), as well as

- Arrangement and attachment of the PCB (12) with the at least one switching element (11, 11a) and the spring element (20) to the support element (13), meaning that the at least one switching element (11, 11a) that is arranged in a pass-through opening (13a) of the support element (13) is in contact with a cooling surface (16) of the housing (2).
Process according to claim 21, characterised in that a power supply arrangement (5) is premounted to the support element (13) as a modular component and the arrangement (5) is both arranged with and attached to the support element (13) on the housing (2) of the device (3), meaning that the at least one switching element (11, 11a) that is arranged in the pass-through opening (13a) of the support element (13) is in contact with the cooling surface (16) of the housing (2).
Process according to claim 22, characterised in that a mounting device (23) is used to move the switching element (11, 11a) into a mounting position in a direction towards the PCB (12) and against the direction of action of a compressive force generated by the spring element (20) and that the mounting device is then removed after establishing the connections of the switching element (11, 11a) to the PCB (12).
Process according to one of the claims 21 to 23, characterised in that the surface of the switching element (11, 11a) that is aligned with the housing (2) is pressed against the cooling surface (16) of the housing (2) as a result of the force generated by the spring element (20).
Use of a device to drive a compressor, in particular an electric motor, for compressing a vaporous fluid, according to one of the claims 1 to 20 for a compressor of a refrigerant in a refrigerant circuit of a motor vehicle air-conditioning system.