FR3071697A1 - COMPRESSOR ELECTRICAL CONTROL UNIT, COMPRISING A PULP SEALING DEVICE - Google Patents

Abstract

Electric control box (22) intended to equip a compressor (1), comprising a box (25), a cover (13), a control module (8) of an electric motor (7) of the compressor (1) and a sealing device (24) sealing between an environment outside the electrical control box (22) and a cavity (10) of the electrical control box (22) arranged to receive the control module (8), characterized in that the sealing device (24) is adhered to at least one sealing surface (40, 50) of the electrical control box (22). Use in motor vehicles.

Description

ELECTRICAL CONTROL BOX FOR COMPRESSOR, COMPRISING A SEALING DEVICE IN THE FORM OF PASTE

The field of the present invention is that of compressors equipping air conditioning installations for motor vehicles. The invention relates more specifically to the sealing methods of such a compressor.

Air conditioning systems for motor vehicles include a closed circuit inside which pressurized refrigerant circulates. Successively, depending on the direction of flow of the refrigerant through it, the air conditioning circuit essentially comprises a compressor, a condenser, a pressure reducer and an evaporator.

The compressor comprises a body provided with an inlet mouth through which the fluid is admitted at low pressure inside the body. The fluid then flows through the body from the inlet mouth to a mechanism for compressing the coolant. An outlet mouth is in communication with the compression mechanism for the evacuation of the high pressure fluid out of the body, following its compression.

The compression mechanism is driven in rotation by an electric motor, the implementation of which is regulated by a control module. The electric motor and the control module are embedded inside the body. The compressor is commonly supplied from an electrical harness coming from the vehicle's electrical network. In this context, the control module is necessarily powered by at least one electrical connector connected to the electrical harness located outside the compressor. Furthermore, this control module is arranged within an electrical control box, comprising a box covered by a cover, fixed to the body.

The parts housed in the compressor body are fragile and sensitive to external aggressions. In order to ensure the longevity of this compressor, it is therefore necessary to seal the electrical control box, in particular at the level of its cover. A sealing device, for example a seal, can thus be arranged between this cover and the electrical control unit.

The cover is most often obtained by a stamping process, the box of the electrical control unit being obtained by a molding process. The box of the electrical control unit resulting from this molding process, once solidified, leaves a surface condition for a seal surface which is poor, in any case incompatible with an independent independent seal. An additional deburring step is therefore necessary to flatten the joint surface and thus allow optimal contact between the independent attached joint and the box of the electrical control box, which in turn ensures better sealing of the assembly.

However, this sealing requires one or more steps of deburring the casing of the electrical control box to be optimal. This additional compressor manufacturing step is costly, both in financial and time terms, equipment manufacturers and car manufacturers therefore have every interest in limiting or even eliminating these expenses.

An object of the present invention is to solve this problem by proposing an electric compressor having a good level of tightness to the external, lasting environment and capable of preventing the introduction of foreign bodies, in particular liquid, into the compressor, the simplified manufacturing makes it possible to limit the machining steps and therefore to reduce its manufacturing cost.

The object of the present invention thus relates to an electrical control unit intended to equip a compressor, comprising a box, a cover, a control module of an electric motor of the compressor and a sealing device ensuring a seal between an environment external to the electrical control unit and a cavity of the electrical control unit arranged to receive the control module, the sealing device being adherent on at least one seal face of the electrical control unit.

An electrical control box thus arranged ensures an optimal seal between the environment outside the electric control box and the cavity inside thereof, by allowing to dispense with at least one deburring step following molding. parts of this electrical control box.

The electrical control unit according to the invention advantageously comprises any one of the following characteristics, taken alone or in combination:

- The sealing device is in contact with the box of the electrical control box on a joint surface, the joint surface having at least one roughness characterized by an average roughness Ra of between o, oi and 500 micrometers. The roughness forms on the joint surface for example a plurality of grooves, that is to say projections separated by hollows. The average roughness Ra is defined as being the average over the joint surface of the absolute values of the deviations between a given point of the roughness and a median plane, located at equal distance between a first plane passing through the highest projection of the roughness and a second plane passing through the deepest of the hollows, the first plane and the second plane being parallel to each other. The measurement of a deviation is made in a longitudinal direction. Roughness is present on all or part of the joint surface,

- the seal surface is a first seal surface extending over an edge of the box of the electrical control box or a second seal surface extending over the cover of the electrical control box. In a preferred configuration, the sealing device is at least in contact with the first seal surface and the second seal surface. Preferably, the sealing device is adherent on the first joint surface and on the second joint surface,

- the first joint surface and the second joint surface each extend in parallel planes with one another. This arrangement is effective once the cover is in place on the electrical control unit. In this configuration, the joint surfaces face each other, that is to say they are arranged opposite one another. This configuration notably ensures the easiest optimal distribution of the sealing device,

- the sealing device is a paste comprising silicone. Such a sealing device is applied to the joint surface (s) in liquid or gelled form. In this form, the sealing device applied to the joint surface covers the roughness of the joint surface and fills the spaces between the roughness, thus ensuring a seal between the environment outside the electrical control box and the cavity at the inside this electrical control box. The roughness also has the effect of increasing the useful contact surface for the sealing device, which increases the holding of the sealing device on the joint surface,

- the sealing device is a paste of the Dow Corning® brand, reference Q3-3636,

- the sealing device extends over the joint surface continuously. Continuously means that the sealing device does not stop and is formed in one piece,

- the roughness extending over the joint surface prevents the use of a sealing device known from the prior art, in particular an O-ring. Such a joint requires deburring the joint surface to ensure its function,

- the electrical control unit comprises a longitudinal extension forming a body and delimiting a housing arranged to receive a mechanism for compressing a coolant. This longitudinal extension of the electrical control box extends in a direction opposite to the cover,

- the cover is obtained by a stamping process, while the electrical control box is obtained by a molding process. More specifically, the cover and / or the electrical control box are made of aluminum or an aluminum-based alloy.

The invention also relates to a compressor for an air conditioning installation of a vehicle, the compressor extending along a longitudinal axis and comprises a body housing at least one mechanism for compressing a refrigerant, and an electric motor. driving the compression mechanism, the compressor comprising an electrical control unit as defined above. The compressor extends in a longitudinal direction along which are distributed at least the compression mechanism, the electric motor, the control module and the cover.

The invention also relates to a vehicle comprising a compressor according to the present invention.

Finally, the invention relates to a method of mounting a compressor for an air conditioning installation of a vehicle, the compressor comprising at least one electrical control unit comprising a box and a cover assembled to delimit together a cavity which receives a compressor control module, the method comprising at least one step of molding the box of the electrical control box and a step of applying a sealing device in the form of paste on at least one joint surface of the box and / or of the cover, the joint surface of the box having a roughness characterized by an average roughness Ra of between o, oi and 500 micrometers. More particularly, the sealing device is applied in liquid or gelled form. This liquid or gelled form allows the sealing device to flow into all the interstices between the roughnesses, and thus to cover the roughnesses to their base to ensure optimal sealing.

The mounting method can also include an intermediate step of preparing the sealing device, during which the sealing device is obtained by a mixture between a base and a catalyst. This additional preparation step can be carried out before, simultaneously or consecutively with the step of molding the electrical control unit and / or the cover, and in any case before the step of applying the sealing device to the bearing surface. seal.

Other details, characteristics and advantages of the present invention will emerge more clearly on reading the detailed description given below for information, in relation to the various embodiments illustrated in the following figures:

- Figure 1 is a schematic representation of a compressor according to the present invention;

- Figure 2 is a perspective view of an electrical control unit according to the present invention;

- Figure 3 is a sectional view of the configuration of the sealing device, according to a plane P visible in Figure 2;

- Figure 4 is a perspective view of an electrical control box without its cover and revealing an internal cavity in the electrical control box.

It should first of all be noted that the figures show the invention in detail in order to implement the invention, said figures can of course be used to better define the invention, if necessary.

In the following description, the longitudinal, vertical or transverse designations refer to the orientation of the electrical control unit according to the invention. The longitudinal direction corresponds to the main axis of elongation of the compressor comprising the electrical control unit according to the invention, in which its largest dimension extends. The vertical direction and the transverse direction correspond to a radial direction, that is to say extending perpendicular to the longitudinal direction. The longitudinal, transverse and vertical directions are also visible in a L, V, T trihedron shown in the figures.

In FIG. 1 is illustrated a compressor 1, otherwise called an electric compressor, organized to equip an air conditioning installation equipping a motor vehicle. The compressor 1 comprises a body 2 having a generally cylindrical conformation, extending along a longitudinal axis X.

The body 2 comprises an inlet mouth 3 and an outlet mouth 4 of a cooling fluid, the latter circulating in the body 2 from the inlet mouth 3 towards the outlet mouth 4 along and / or in components installed inside the body 2.

This body 2 defines at least one housing 11 in which extends a compression mechanism 5 which compresses the refrigerant. The compression mechanism 5 is operated, via a drive shaft 6, by an electric motor 7 received in the housing 11, inside the body 2. According to an exemplary embodiment, such an electric motor 7 is a three-phase electric motor. The compression mechanism 5 is for example with spiral compression mechanisms, one of the spirals being fixed while the other spiral oscillates.

This electric motor 7 is electrically supplied and regulated by a control module 8 via an electrical connection 9. The control module 8 is disposed in a cavity 10 of an electrical control box 22. In any state of cause, the cavity 10 is separated from the housing 11 by at least one wall 12 traversed by the electrical connection 9. The cavity 10 is here for example formed in the extension of the compression mechanism 5 and the electric motor 7 along the axis longitudinal X of the body 2, the electric motor 7 being arranged longitudinally between the compression mechanism 5 and the control module 8. The control module 8 is an electronic device configured at least to transform a direct current coming from the electrical network of the vehicle in an alternating current suitable for actuating the electric motor 7.

The cavity 10 comprising the control module 8 must necessarily contain a controlled atmosphere, devoid of any body, liquid or element liable to damage the control module 8, in particular the control electronics and / or the power electronics constituting it. . The control module 8 thus comprises first electronic components dedicated to the management of the power supplied to the electric motor 7 and second electronic components dedicated to the management of the control, signal and / or diagnostic information 14 relating to the compressor 1.

The electrical control box 22 comprises a box 25 is closed by a cover 13, which together define the cavity 10. The cover 13 is a means for closing the cavity 10. Between this cover 13 and the electric control box 22, a sealing device 24 extends while adhering to both the cover 13 and to the casing 25. This sealing device 24 makes it possible to ensure a seal between the cover 13 and the electrical control box 22, as described below -after. Along the longitudinal axis X of the body 2, the control module 8 is installed in the cavity îo and its electrical connection with the environment outside the compressor i occurs by passing, for example, through the cover 13. This arrangement facilitates the electrical connection of the control module 8 to the outside of the electrical control box 22, that is to say to a bundle 15 of electrical supply belonging to the vehicle. Such an electrical connection is made by means of at least one electrical connector 16 whose function is to transport electrical energy from the bundle 15 to the control module 8.

This electrical connector 16 extends between a first end located inside the cavity 10 and a second end located outside the compressor 1.

This electrical connector 16 comprises a first end which extends inside the compressor 1 and a second end situated outside the compressor 1. The first end of the electrical connector 16 is arranged so that it can be soldered to the control module 8, or nested therein. The second end of the electrical connector 16 is intended to be fitted into a socket 19 generally connecting the control module 8 to the harness 15 for the electrical supply of the vehicle. FIG. 1 illustrates a situation where the electrical connector 16 forms a male end piece, while the socket 19 forms a female end piece, but the invention of course covers a reverse arrangement of the electrical connector 16 and the socket 19.

According to one of the embodiments of the cover, the electrical connector 16 may optionally also include a base configured to attach the electrical connector 16 to the cover 13. The electric compressor 1 illustrated in FIG. 1 comprises two electrical connectors organized and installed such as described above. The electrical connector referenced 16 is here an electrical power connector, while an electrical control connector 20 also passes through the cover 13.

As illustrated, the cover 13 is fixed to a box 25 of the electric control box 22, preferably directly on the box 25, and covers the whole of a longitudinal end of the electric control box 22, completely closing the cavity io.

Figure 2 illustrates more specifically an electrical control unit 22 as described above.

The electrical control unit 22 comprises the box 25 has the general shape of a flattened circular cylinder, open at a first longitudinal end 26. This opening of the box 25 is closed by the cover 13.

At a second longitudinal end 28, opposite the first longitudinal end 26 relative to an edge 27 of the electrical control box 22, the box 25 is arranged to receive the body 2 of the compressor 1.

The cover 13 is arranged to obstruct the opening of the electrical control box 22, that is to say that it has a generally similar shape, seen in a projection of longitudinal axis X, to the electric control box 22, its thickness being less than that of the electrical control box 22.

At the first longitudinal end 26, the electrical control unit 22 includes a first seal surface 40, that is to say a flat section capable of receiving the sealing device 24. The first seal surface 40 extends more particularly on a rim of the box 25 of the electrical control unit 22, the rim being disposed at the first longitudinal end 26. The first seal bearing surface 40 faces a second seal bearing surface 50, disposed on a rim of the cover 13. The sealing device 24 extends between the first joint surface 40 and the second joint surface 50, and adheres to at least one of the joint surfaces 40, 50. The first joint surface 40 comprises at least one roughness 44, resulting from the method of manufacturing the electrical control unit 22, and more particularly described in FIG. 3. In the following description, a joint surface 40, 50 denotes indifferent remment the first joint seat 40, the second joint seat 50 or both.

The electrical control unit 22 described in FIG. 2 is notably different from that illustrated in FIG. 1 in that the electrical connector 16 and the electrical control connector 20 extend not through the cover 13, but rather through the edge 27 of the electrical control unit 22, respectively in a first connection area 30 and a second connection area 34.

The first connection zone 30 comprises an orifice, called the first orifice 31, of oblong shape made to allow the insertion of the electrical connector 16 so that it emerges in the cavity 10. The first connection zone 30 also comprises a plurality of fixing holes 32 for fixing the electrical connector 16 to the electrical control unit 22. The first connection area 30 is planar. It will however be understood that another configuration is possible as long as it makes it possible to accommodate the fixing of the socket 19.

The second connection area 34 extends in a plane parallel and distinct from a plane where the first connection area 30 extends. The second connection area 34 is formed in a similar manner to the first connection area 30, in particular in that it has a planar shape and comprises an orifice, here second orifice 35, for the passage of the electrical control connector 20, and a plurality of fixing holes 36 for fixing the electrical control connector 20 on the electrical control box 22.

The electrical control box 22 also comprises at least one fixing portion 38, disposed at the second longitudinal end 28 of the electric control box 22 opposite the first longitudinal end 26, the fixing portion 38 being arranged to allow the fixing of the box. electric control 22 on the body of the compressor 1. The fixing portion 38 comprises for example a tapped hole collaborating with a fixing device, arranged on the compressor 1, to allow the coupling of these two parts. The attachment portion (s) 38 extend radially outward from the electrical control unit 22.

FIG. 3 illustrates the interaction between the cover 13, the electrical control unit 22 and the sealing device 24.

The first joint seat 40 extends along a first plane 42 perpendicular to the longitudinal direction L. The second joint seat 50 extends along a second plane 52 perpendicular to the longitudinal direction

L. It follows from this arrangement that the first plane 42 and the second plane 52 are parallel, the first joint surface 40 and the second joint surface 50 also being parallel to each other. This arrangement greatly simplifies the application of the sealing device 24 according to the invention, the sealing device 24 thus being able to be applied to a perfectly horizontal surface, thus avoiding dispersal out of the electrical control box 22 or into the cavity 10 This application is done in a uniform size layer that is easier to manage, rather than an uneven layer in a portion of a joint surface 40, 50.

The first seal surface 40 comprises at least one roughness 44, resulting from the molding of the box 25 of the electrical control unit 22. This roughness 44 is usually removed from the part during a deburring step, but the electrical control unit according to the invention allows the manufacturer to do without such a step.

The roughness 44 forms on the first joint surface 40 a plurality of grooves, that is to say projections separated by hollows.

The roughness 44 of the first joint surface 40 is characterized by an average roughness Ra. The average roughness Ra is defined as being the average over the first joint surface 40 of the absolute values of the deviations between a given point of the roughness 44 and a median plane, located at equal distance between a first plane passing through the highest projection of the roughness 44 and a second plane passing through the deepest of the hollows, the first plane and the second plane being parallel to each other. The measurement of a deviation is made in a longitudinal direction L.

The average roughness Ra is between 0.01 and 500 micrometers.

The interior of the electrical control unit 22 is more particularly visible in FIG. 4, which shows the electrical control unit 22 without the cover 13. In particular, this cavity 10 can be seen in this figure, arranged to receive a control module.

More particularly, this figure illustrates the sealing device 24, visible on the first seal surface 40 formed on a flange of the electrical control box 22. The sealing device 24 extends continuously along the first surface seal 40, that is to say without interruption. In this configuration, the sealing device 24 consists of a strip of material without a defined end.

The electrical control box 22 also includes a plurality of fixing members 37, here screws visible in FIGS. 2 and 4, arranged to collaborate with fixing holes to hold the cover 13 on the electric control box 22. The fasteners 37 are arranged radially outside a space defined by the sealing device 24. The fasteners 37 pass through the cover 13 through openings coinciding with the fastening holes of the electrical control box 22, of so as to fix the cover 13 and to close the cavity 10. In this way, in collaboration with the sealing device 24, the sealing of the cavity 10 relative to the external environment of the electrical control box 22 is ensured. The fixing members 37 are here six fixing screws, but it will be understood that other types of fixing and / or a different number of fixing can be used without distorting the invention.

FIG. 4 finally illustrates a bottom 60 of the box 25, and in particular a light 62 extending partially within this bottom 60. The light 62 is arranged so as to receive the electrical connection 9 making it possible to transmit from the control module 8 towards the electric motor 7 the electric current supplying this electric motor 7.

An example of manufacturing an electrical control unit 22 as defined above will now be described. It will be understood that the following does not in any way constitute a limitation of the invention, certain steps being able to be reversed or carried out simultaneously.

The cover 13 comes from a step of stamping a sheet of a material such as aluminum or an aluminum alloy. The box 25 of the electrical control unit 22, for its part, comes from a step of molding a material capable of fulfilling its function, in particular aluminum or an aluminum alloy. Before, simultaneously or following this molding, the sealing device 24, here a paste of the Dow Corning® brand reference Q3-3636, is prepared according to the instructions relating to this particular sealing device 24. In particular, the sealing device 24 is obtained by mixing a base with a catalyst. The catalyst has the effect of allowing the base to solidify or crosslink into a solid sealing device. The paste has, in the liquid state as in the solid state, properties of strong adhesion, that is to say which allows it to adhere to the surfaces on which it is deposited.

After a preliminary cleaning but without deburring or machining step of the first joint surface 40 of the box 25, the sealing device 24 in liquid or gelled form is placed on one, the other or both surfaces joint 40, 50. This sealing device is cast on the joint seat 40, 50 and forms a bead adhering to the bearing which receives this bead. The sealing device 24, thanks to the fact that it adheres to the surfaces it touches, thus makes it possible to dispense with the deburring step, a step which would be necessary for the effective application of a traditional seal. Indeed, such a seal is not capable of filling the interstices consecutive to the level of roughness which cuts out from a step of molding the box 25, which in turn would cause fluid communication between the cavity 10 and the environment outside electrical control unit 22, which the invention seeks to avoid.

Before the sealing device 24 becomes solid, the cover 13 is attached to the box 25 of the electrical control box 22 and fixed by the fixing members 37. By fixing on the box 25, the cover 13 will compress the sealing device 24 which will adhere to the cover 13 in addition to adhering to the casing 25 of the electrical control box and thus ensuring the seal between the environment outside the electrical control box 22 and the cavity 10 inside this one. The sealing device 24, once dry, is integral with at least one joint surface 40, 50 of the electrical control unit 22, and for example of the first joint surface 40 of the box 25 of the electrical control unit 22 and of the second seal surface 50 of the cover 13. The invention is thus recognizable when, when the cover 13 is removed from the box 25, part of the sealing device 24 adheres to the first seal surface 40 and another part of the sealing device 24 adheres to the second seal surface 50 of the cover 13. In such an arrangement, the reuse of the sealing device 24 is impossible, the removal of the cover 13 from the electrical control box 22 therefore requires cleaning joint surfaces 40, 50 and a new application of a sealing device 24 before reassembling the cover 13 on the box 25 of the electrical control unit 22.

An electrical control unit 22 thus mounted can then be assembled with other parts in order to obtain a compressor 1. Thus, the electrical control unit 22 is attached to a body 2 of the compressor 1, so that the connection electric 9 between the control module 8 and the electric motor 7 is effective. The electrical control box 22 is then fixed to the body 2 of the compressor 1, in particular by cooperation between a fixing member and the fixing portion 38 of the electric control box 22.

The compressor 1 obtained by this process is then installed in the vehicle. The inlet mouth 3 and the outlet mouth 4 are each connected to conduits in which the refrigerant circulates, while the electrical connector 16 and the electrical control connector 20 are connected to the electrical network of the vehicle. The air conditioning circuit is then charged with refrigerant, allowing the circuit to fulfill its primary air conditioning function.

The foregoing description clearly explains how the invention makes it possible to achieve the objectives which it has set itself and in particular to propose an electrical control unit allowing simple assembly in that it limits the number of operations to be carried out thus reducing the design and manufacturing costs of a compressor for a vehicle air conditioning installation.

Of course, various modifications can be made by a person skilled in the art to the adapter which has just been described by way of nonlimiting example, as soon as at least one electrical control unit comprising a sealing device integral with at least one joint surface of this electrical control unit.

In any event, the invention cannot be limited to the embodiments specifically described in this document, and extends in particular to all equivalent means and to any technically effective combination of these means.

Claims (10)

1. Electric control unit (22) intended to equip a compressor (1), comprising a box (25), a cover (13), a control module (8) of an electric motor (7) of the compressor (1 ) and a sealing device (24) ensuring a seal between an environment external to the electrical control unit (22) and a cavity (10) of the electrical control unit (22) arranged to receive the control module (8), characterized in that the sealing device (24) is adhered to at least one seal surface (40, 50) of the electrical control unit (22). 2. An electrical control unit (22) according to the preceding claim, in which the joint surface (40.50) has at least one roughness (44) characterized by an average roughness Ra of between 0.01 and 500 micrometers. 3. An electrical control unit (22) according to any one of the preceding claims, in which the seal surface (40, 50) is a first seal surface (40) extending over a rim of the box (25) of the electrical control unit (22) or a second seal surface (50) extending over a flange of the cover (13) of the electrical control unit (22). 4. Electrical control unit (22) according to the preceding claim, wherein the sealing device (24) is adhered to the first seal surface (40) and to the second seal surface (50). 5- electrical control unit (22) according to any one of the preceding claims, wherein the sealing device (24) is a paste comprising silicone. 6. An electrical control unit (22) according to the preceding claim, in which the sealing device (24) is a paste of the Dow Corning® brand, reference Q3-3636. 7. An electrical control unit (22) according to any one of the preceding claims, comprising a longitudinal extension forming a body (2) and delimiting a housing (11) arranged to receive an electric motor (7) of a coolant. 8. Compressor (1) for an air conditioning installation of a vehicle, the compressor (1) extends along a longitudinal axis (X) and comprises a body (2) housing at least one compression mechanism (5 ) of a coolant and an electric motor (7) driving the compression mechanism (5), the compressor (1) comprising an electrical control unit (22) according to any one of the preceding claims. 9. Compressor (1) according to the preceding claim, extending in a longitudinal direction along which are distributed at least the compression mechanism (5), the electric motor (7), the control module (8) and the cover (13). 10. A method of mounting a compressor (1) for an air conditioning installation of a vehicle, the compressor comprising at least one electrical control unit (22) comprising a box (25) and a cover (13) assembled to delimit together a cavity (10) which receives a control module (8) of the compressor (1), method comprising at least one step of molding the box (25) of the electrical control box (22) and a step of application of a sealing device (24) in the form of paste on at least one joint surface (40, 50) of the box (25) and / or of the cover (13), the joint surface (40) of the box (25) having a roughness (44) characterized by an average roughness Ra of between 0.01 and 500 micrometers.