FR2997797A1 - Assembly for electric compressor utilized for liquid refrigerant e.g. R134a circuit in electric car, has sealing unit insulating electric connection element of wall separating motor from control device on level of connection opening - Google Patents

Abstract

The assembly has an electric connection device (5), and a sealing unit (91), where the electric connection device includes a connection block (7) for connection to an electrical motor of a compressor. An electric connection element (72) is adapted in the connection block to cooperate with a connection terminal (6) of a control device or inverter of the motor through a connection opening (74). The sealing unit insulates the electric connection element of a wall (4) separating the motor from the control device on a level of the connection opening.

Description

An assembly comprising an electrical connection device for a compressor and a sealing means and a compressor comprising such an assembly. The invention relates to an assembly comprising an electrical connection device for a compressor and a sealing means and a compressor comprising such an assembly. It will find its applications, in particular in the field of refrigerant circuit compressors fitted to a motor vehicle.

In such a circuit, the coolant is circulated inside an air conditioning circuit via a compressor. Conventionally, this compressor is of the mechanical type and its rotation is driven by means of a pulley connected to the internal combustion engine of the vehicle by a belt.

The number of hybrid vehicles, that is to say with internal combustion engine coupled to an electric motor, or all electric, that is to say exclusively powered by an electric machine, is constantly increasing because of the rarefaction of fossil fuels that fuel vehicles equipped with internal combustion engines.

The mechanical energy usually supplied by the internal combustion engine is therefore less available or completely unavailable for the case of all-electric vehicles. Moreover, for reasons of overall efficiency, the preferred solution for driving a compressor in a hybrid or electric vehicle is by feeding an electric motor driving the compressor rather than a belt at the output of the electric machine. However, a particular vehicle model can be sold in a version equipped with an internal combustion engine and a mechanical compressor but also in a version equipped with an electric propulsion engine requiring the use of a compressor electric. These two types of compressors are based on different technologies that require the use of a different lubricant. Indeed, the presence of high electric potentials in an electric compressor requires the use of a dielectric lubricant which has electrical insulation properties superior to those of a conventional lubricant used in a mechanical compressor.

In addition to the fact that the cost of a dielectric lubricant is higher than that of a conventional lubricant used for a mechanical compressor, such a situation requires the manufacturer of motor vehicles to provide management of two types of lubricant at the level of the chain vehicle manufacturing. This management of two lubricants is particularly cumbersome to implement and increases the risk of errors in the production line. In order to solve this drawback, the Applicant proposes an electric compressor adapted to use a conventional lubricant (non-dielectric) traditionally used for a mechanical compressor. Such an approach goes against established prejudices which consider that a conventional lubricant is, by nature, unsuitable for an electric compressor since its electrical insulation properties are lower than those of a dielectric lubricant. For this purpose, the invention relates to an assembly comprising an electrical connection device for a compressor and a sealing means, the electrical connection device comprising a connection block to an electric motor of the compressor and at least one suitable electrical connection element. in said connection block for cooperating with a connection terminal of a control device of said electric motor through a connection opening of said connection block, said sealing means being configured to isolate, at said connection opening, the electrical connection element of a wall separating the electric motor from the control device. The use of a sealing means makes it possible to provide a barrier between the parts under tension inside the electrical connection device and the metal parts of the wall separating the electric motor from the control device and those close to the electrical connection device with which a leakage current could be established. The sealing means compensates for a lack of electrical insulation of the lubricant, at said connection opening in order to limit the risk of forming an electric arc between the wall, whose electrical potential is grounded, and the or the electrical elements of the connection block having a high electrical potential.

According to one aspect of the invention, said assembly comprises at least one electrically insulating element mounted on the connection block so as to reinforce the insulation between the electrical connection element and said wall. The electrically insulating element forms a insulation cover, and increases the distance between the wall and the electrical element or elements of the connection block. Thus, even if the wall of the engine compartment is coated with lubricant, the risk that an electric arc is formed between the wall and an electrical element is low since the electrically insulating element together with the sealing means compensate. a lack of electrical insulation of the lubricant. According to one aspect of the invention, the electrical connection device maintains said sealing means. By maintaining said sealing means, the electrical connection device allows the assembly to be secured. Thus, the risk of loss or displacement of the sealing means is reduced, especially during assembly and / or disassembly of the assembly with the connection terminal. Advantageously, the sealing means is fixed to the electrically insulating element. The sealing means is, in particular, overmoulded on the electrically insulating element. By fixing the sealing means on the electrically insulating element, its positioning is favored with respect to the connection block during the assembly of the electrical insulation element with the connection block in a first step and then of this assembly. with the connection terminal.

According to an exemplary embodiment of the invention, said sealing means is maintained between the electrically insulating element and the connection block. The sealing means is thus blocked between the electrically insulating element and the connection block, in particular following the mounting of the electrically insulating element on the connection block. Advantageously, said electrically insulating element comprises a housing intended to be traversed by said connection terminal and provided with a shoulder, said sealing means being located in the housing and held against the connection block by said shoulder. According to one aspect of the invention, said shoulder maintaining said sealing means is beveled outwardly of the electrical connection device. According to an exemplary embodiment of the invention, said assembly comprises a plurality of sealing means, said sealing means being interconnected mechanically. It is thus possible, in the case of a control device comprising several rods, to simultaneously place all the sealing means during assembly of the assembly which facilitates, in particular, the mounting of the means of sealing on the electrical connection device and reduces the risk of misplacement and / or loss of one or more sealing means.

Advantageously, the sealing means is intended to electrically isolate the connection terminal and the wall. The sealing means then fills both an insulation function of the electrical connection element with respect to the wall at said connection opening and an electrical insulation function. Thus, thanks to the invention, it is no longer necessary to provide an electrical insulation means in addition to a sealing means, thereby reducing the manufacturing costs of the assembly. According to this aspect of the invention, a first portion of the sealing means may extend longitudinally in a direction parallel to an extension direction of the connection terminal. The sealing means can thus continue the electrical isolation of the connection terminal in the direction of longitudinal extension of the connection terminal, that is to say on a large part of the connection terminal.

According to an exemplary embodiment of the invention, said sealing means is in contact with the electrical insulation element and intended to be in contact with said connection terminal and / or the wall. Advantageously, a second portion of the sealing means is configured to be located between the electrical insulation element and said wall. The second part ensures, in particular, the tightness of the assembly with respect to the fluid flowing outside the electrical connection device. According to one aspect of the invention, said sealing means is intended to be bonded to the wall and / or to the electrical terminal. According to an exemplary embodiment, said electrically insulating element comprises a housing intended to be traversed by said connection terminal, said sealing means being located inside the housing. The invention also relates to a compressor comprising an assembly as described above. The invention will be better understood on reading the following description, given purely by way of example, and referring to the appended drawings in which: FIG. 1 is a diagrammatic sectional view of an electric compressor according to the invention; - Figure 2 is a schematic view showing, in a longitudinal sectional plane, a connection terminal of the compressor and an assembly according to the invention comprising an electrical connection device and a sealing means 30; - Figure 3 is a schematic view, showing on the same sectional plane as that of Figure 2, the corresponding assembly electrically connected to the connection terminal of the compressor; Figure 4 is a perspective view of the assembly of Figure 2, illustrated in a sectional plane parallel to that used in said figure; - Figure 5 is a top view of the sealing means of Figure 4; - Figure 6 is a view similar to that of Figure 3 showing another embodiment of the invention; - Figure 7 is a sectional view along a plane orthogonal to that of Figure 2 showing an alternative embodiment of the assembly of the invention at its sealing means.

It should be noted that the figures disclose the invention in detail to implement the invention, said figures can of course be used to better define the invention where appropriate. FIG. 1 illustrates a schematic view of an electric compressor 9 comprising an electrical connection device 5 of the assembly according to the invention. The compressor 9 is an electric compressor in that it incorporates an electric motor 2 which drives a compression mechanism 3. The electric motor 2 comprises a stator and a rotor integral with a motor shaft which extends longitudinally along an axis H as shown in Figure 1. The compression mechanism 3 comprises fixed parts and moving parts, the latter being rotated by the shaft of the electric motor 2. The compression mechanism 3 is of the spiral compression type ( Scroll in English) or of the pallet type or the piston type, these examples being given for illustrative purposes without limiting the scope of the invention.

The compressor 9 further comprises a control device 1 of the electric motor 2. This control device 1 is notably an inverter (inverter in English) transforming a direct current coming from an on-board network of the vehicle into a sinusoidal current supplying the power supply. electric motor 2.

The compressor 9 is delimited vis-à-vis its external environment by a housing. This housing is an aluminum piece or aluminum alloy, hollow circular shape comprising a peripheral wall which delimits an internal volume. This housing comprises, in this example, at least three compartments, which take the form of cavity or housing formed inside the housing, in which are respectively mounted the control device 1, the electric motor 2 and the compression mechanism 3, as shown in Figure 1. These compartments are separate volumes separated from each other by at least one wall. It will thus be understood that these compartments can be delimited by a single peripheral part which forms the housing or, for example, by separate sub-housings dedicated to each compartment and assembled together to form the compressor 9.

In this example, the compressor 9 comprises a main housing, forming a motor compartment 20, which houses the electric motor 2 and on which is reported, at a first end, a housing forming a control compartment 10 in which the device is housed. 1 and at a second end, opposite the first end relative to the electric motor 2, a housing forming a compression compartment 30 in which is housed the compression mechanism 3. In other words, the engine compartment 20 is interposed between the control compartment 10 and the compression compartment 30. In operation, a fluid or mixture consisting of a coolant mixed with a lubricant enters the engine compartment 20 and circulates around and in the electric motor 2. The coolant is a subcritical fluid such as for example R134a but it can also be a supercritical refrigerant such as p for example carbon dioxide known as R744. The lubricant is for example a polyalkylene glycol type compound.

The fluid flows in the engine compartment 20 and the compression compartment 30 in which is housed the compression mechanism 3. The latter ensures the desired increase in pressure and temperature of the refrigerant. The circulation of the coolant in contact with the engine allows the cooling of the latter. The engine compartment 20 is separated from the control compartment 10 by a wall 4 which prevents the penetration of the fluid into the control compartment 10. It is thus clear that the fluid present in the engine compartment 20 does not circulate in the control compartment 10 to protect the controller 1 which includes elements having high electrical potentials.

As a reminder, the control device 1 supplies the electrical energy to the electric motor 2. Since these components are in two separate compartments, it is necessary to electrically connect the control device 1 to the electric motor 2. To do this, the control device electrical connection 5 is mounted at the interface between the engine compartment 20 and the control compartment 10.

A plurality of connection terminals 6 of the control device 1 is connected to the electric motor 2 by a connection block 7 of said connecting device. In this example, the connection terminals 6 are three in number and are respectively received in three connection openings of the connection block 7.

With reference to FIGS. 2 and 3, the connection block 7 here comprises a plastic body 71 of generally parallelepipedal shape which extends in length in the X direction, in width in the Y direction and in height in the Z direction. connection block 7 accommodates at least one connection element 72, here three, mounted for example removably in the interior volumes of the body 71.

Said connection elements 72 make it possible to electrically connect the connection terminals 6 to the motor 2 by electrical cables 73. These connection elements 72 are known to those skilled in the art and will not be detailed further. The connection block 7 is removable connection terminals 6 mounted in the wall 4 so as to allow mounting of the compressor in a modular manner. Each of the connection terminals 6 passes through the wall 4 and is fixed thereto at ring 11, preferably made of glass, in order to isolate them electrically from the wall 4. Thereafter, the terms "back" and "front" are defined with respect to the X axis which is oriented from the rear to the front in FIG. 2. In the same way, the Z axis is oriented from the bottom to the top in FIG.

A rear face F1 of the body 71 of the connection block 7 is open to allow the introduction of the three connection elements 72 and the passage of the electrical cables 73.

To allow the connection of a terminal 6 to a connection element 72, an upper face F3 of the body 71 comprises connection openings 74 of diameter of the order of 3 mm, preferably 3.7 mm. Given these openings formed in the body 71 of the connection block 7, there are paths through which an electric arc can be formed between the wall 4 whose electrical potential is zero and between an electrical element of high potential of the connecting device. 5. In order to increase the electrical insulation of the connection device 5 and as illustrated in FIGS. 2 and 3, an electrically insulating element 8 is here mounted on the connection block 7, in particular in a removable manner, so as to isolate the electrical connection element 72 of the wall 4 between the electric motor 2 of the control device 1. The electrically insulating element 8 is disposed between the wall 4 and the connection block 7.

In this example, the electrical insulation element 8 is in the form of a cover 8. It goes without saying that the electrically insulating element 8 can be in various forms, for example, in the form of a block of insulation, etc. For the sake of clarity, only the term "hood" is used in the following description.

The insulation cover 8 may comprise an interface partition 81, placed between the wall 4 and the connection block 7, which covers the upper face F3 of the body 71 and a rear wall 83 arranged to close the rear face F1 of the body 71. In this example, the insulation cover 8 is in one piece and is adapted to elastically deform during assembly, the insulation cover 8 then being held on the connection block 7 by snapping. In particular, the interface partition 81 is elastic so as to be deformable when it is mounted on the body of the connection block 7. The cover comprises, for example, a locking means 88, located at its front face and snap on the front face of the connection block 7. The front partition 82 of the cover 8 is flat and extends in the plane (Y, Z), that is to say orthogonally to the interface partition 81 The rear partition 83 of the cover 8 has a complementary shape to the rear part of the body 71 so as to allow optimum cooperation between the connection block 7 and its cover 8. For this purpose, the rear wall 83 comprises mounting pins 86 which extend parallel to the plane (X, Y) and which are arranged to cooperate with the rear portion of the connection block 7. The rear wall 83 of the cover 8 allows, on the one hand, to close the face F1 rear of the connection block and, on the other hand, to allow the passage of s connection cables 73 connected to the connection elements 72 mounted in the body 71. For this purpose, the rear wall 83 comprises a guide sheath 84 extending along the X axis and which comprises three channels for guiding respectively the three cables. connection 73 connecting the three connecting elements 72.

The cover 8 preferably comprises at least one lug 89 ensuring that the electrical connection element 72 is held in position in the connection block 7. In the illustrated examples, the cover 8 comprises two lugs 89 ensuring the holding in position of two electrical connection elements 72 located laterally on the cover 8, that is to say one next to the other along the Y axis. These lugs 89 protrude from the interface partition 81 towards the interior of the electrical connection device of the invention. When mounting the cover 8 on the connection block, the lugs 89 fit inside the electrical connection device 5 by mounting openings in the connection block 7 so that they come to block the elements of connections 72 inside the connection block 7. The pins 89 must thus be large enough to prevent the X-axis translation of the connection elements 72. The cover, mounted on the connection block 7, closes the openings of mounting.

The third connecting element 72 is centrally located with respect to the connection block 7, offset along the X axis with respect to the other two connection elements 72 so that it is located at the top of a triangle. , that is to say here backwards relative to the other two connection elements 72, in order to be able to connect to the three connection terminals 6. In this exemplary embodiment, the rear wall 83 of the electrically insulating element 8 forms a stop for holding in position the third connecting element 72 Each terminal 6 here comprises a conducting rod 61 mounted in an orifice of the wall 4, the ends of the rod 61 projecting respectively in the control and motor compartments 10 20. In this example, the connection terminals 6 extend substantially parallel to the axis H of the motor 2.

In the exemplary embodiments illustrated in FIGS. 2 and 3, each conducting rod 61 is mounted in an insulating plug 62, preferably made of ceramic, which is secured to the wall 4, to avoid the formation of an electric arc between the conducting rod. 61 and the material of the wall 4. For example, the plug 62 of each terminal 6 is held in position by adhesion with the glass rings 11 also surrounding the conductive rods 61. The interface partition 81 is flat and extends in the plane (X, Y). Only housings 100 are formed in the partition 81 to correspond with the connection openings 74 of the body 71. The diameter of the housings 100 is substantially equal to that of the insulating plugs 62 of the connection terminals 6 to allow mounting by complementarity of forms. Such an insulation cover 8 thus makes it possible to avoid arcing between the conductive rods 61 since the insulating cover 8 makes it possible to surround the ceramic insulating plugs 62 as shown in FIG. 3 In order to enhance the sealing of the electrical connection device 5 at the connection openings 74, the invention provides for assembling a sealing means 91 with the electrical connection device 5 in order to isolate the connection element. 72 of the refrigerant circulating inside the engine compartment but outside the electrical connection device 5. The sealing means is here an annular seal. The assembly of the invention comprises a sealing means for each connection terminal 6. Here, it therefore comprises three.

In a particular embodiment, the sealing means 91 is positioned on the electrical connection device 5 so as to be in contact with each connecting rod 61 and so as to bear against the ceramic plug 62 of said connection terminal 6. In the position of use, the sealing means 91 extends here in a plane transverse to the axis in which the connection terminal 6 extends, that is to say in a plane parallel to the plane (X, Y). Such a sealing means 91 improves the sealing of the connection between the connection rod or rods 61 and the connection block 7 by preventing the creation of an electric arc between the electrical connection elements 72 and the wall 4 separating the electric motor 2 from the control device 1. The electrical connection device 5 here mechanically maintains the sealing means 91. In the examples illustrated in Figures 2 to 4, said sealing means 91 is held between the cover 8 and the connection block 7. Thus, when mounting the cover 8 on the connection block 7, the sealing means 91 is blocked between the cover 8 and the connection block 7. The cover 8 comprises a housing 100 accommodating the sealing means 91. This housing 100 comprises a shoulder 101 now bearing the sealing means against the connection block 7. In the embodiments of the invention illustrated in Figures 2 and 3, the shoulder now 101 the sealing means 91 is tapered, especially towards the outside of the electrical connection device 5, that is to say towards the wall 4. The housing 100 then has a conical shape, converging towards the outside However, in the embodiment of FIG. 4, the shoulder 101 extends in a plane parallel to the plane in which the interface bulkhead 81 extends, that is to say, in the embodiment of FIG. that is to say a plane parallel to the plane in which the upper face F3 of the connection block 7 extends.

As explained above, the assembly of the invention may comprise a plurality of sealing means 91. These sealing means 91 are, for example, interconnected mechanically as shown in the example illustrated in FIG. sealing means 91 are here connected by a link 92. In order to receive the link 92, the cover 8 and / or the connection block 7 comprise a groove of complementary shape to the link 92 so as to incorporate it into the device of FIG. electrical connection 5 without altering the tightness of the assembly. This link 92 has the advantage of creating an assembly comprising all of the sealing means 91, which easy their assembly, particularly avoiding that one or more sealing means 91 are found misplaced or removed, for example, at the time of assembling the cover 8 on the connection block 7. In another embodiment illustrated in Figure 6 the sealing means 91 can be fixed on said cover 8. The sealing means 91 is here fixed by overmolding on the cover 8, in particular on the interface partition 81. It is fixed for example inside the housing 100 and in particular against the shoulder 101 of the housing 100. The sealing means 91 is here advantageously under the shape of an annular elastic material. The sealing means 91 will then provide even more ease insulation at the connection openings by a greater deformation around the insulating plug 62 while making the mounting of the cover 8 more simple because the sealing means 91 is then integral with this cover 8. According to an alternative embodiment of the sealing means 91 illustrated in Figure 7, the latter is intended to electrically isolate the connection terminal 6 and the wall 4. In this embodiment of the embodiment of the Thus, it is no longer necessary to have a ceramic plug 62 around the rod 61, which reduces the cost of the assembly comprising the connection terminal.

A first portion 93 of the sealing means 91 extends longitudinally in a direction parallel to an extension direction of the connection terminal 6, that is to say in the direction Z. With this first portion 93, the sealing means 91 form a sleeve extending the electrical insulation between the connection terminals 6 and the wall 4 provided by the glass rings 11. The sealing means 91 thus has the same function of electrical insulation as the plug. ceramic 62 described above. Thus, the sealing means 91 makes it possible to increase the electrical insulation of the connection terminals 6 and possibly to prevent the penetration of liquid into the body 71 of the connection block 7 via the connection openings 74. Said first part 93 of the sealing means 91 is located here inside a housing 103 of the cover 8 crossed by the connection terminal and similar to that presented above. The sealing means 91 comprises, in particular, a second portion 94 located between the electrical insulating element 8 and said wall 4. This second part has the main function of sealing the inside of the assembly. of the invention of the refrigerant. The sealing means 91 is, for example, in contact with the electrical insulation element 8, the connection terminal 6 and the wall 4.

The sealing means 91 is advantageously bonded, in particular by an overmolding method, to the wall 4 and / or to the electrical terminal 6. In all these examples and in general, each sealing means 91 is made of rubber but it goes without saying that any other elastic material compatible with the environment of the compressor could be suitable. A method of mounting the cover 8 on the connection block 7 is now detailed. Thus, the connection cables 73 are first introduced into the channels of the guide sheath 84 of the cover 8 from the rear. Then, the free ends of the connection cables 73 are electrically connected to the connection elements 72. The connection elements 72 are then introduced into the body 71 from the rear face F1 and are thus positioned opposite the connection openings 74 of the face upper body F3 71.

Once the connecting elements 72 mounted in the body 71, in a translationally movable manner along the X axis, the connection block 7 is introduced into the cover 8 so as to insert the lugs 89 inside the mounting openings in order to keep the connection elements 72 in position. The assembly is carried out in such a way as to make the rear portion of the body 71 cooperate with the rear wall 83 of the cover 8. The cover 8 thus ensures the holding in position of the electrical connection elements 72 in the connection block 7 by translation stop. To finalize the assembly, the interface partition 81 of the cover 8 is bent in such a way that a ratchet tooth clings to the plate 81 of the connection block 7. The sealing means 91 are then in position. To remove the cover 8, an operator can simply pull the partition 8 outwardly of the cover 8 to bend the cover 8 and thus release the ratchet tooth. The connection block 7 can then simply be removed from its cover 8. During the electrical connection, the connection block 7 (on which the insulating cover 8 is mounted) is connected to the connection terminals 6 by introducing the conductive rods 61. connection terminals 6 in the connection openings 74 of the body 71 (via the housings 100, 103 of the cover 8) in order to come into contact with the connection elements 72.20

Claims (15)

REVENDICATIONS1. An assembly comprising an electrical connection device (5) for a compressor (9) and a sealing means (91), the electrical connection device (5) comprising a connection block (7) to an electric motor (2) of the compressor (9) and at least one electrical connection element (72) adapted in said connection block (7) for cooperating with a connection terminal (6) of a control device (1) of said electric motor (2) through a connection opening (74) of said connection block (7), said sealing means (91) being configured to isolate, at said connection opening (74), the electrical connection element (72) from a wall (4) separating the electric motor (2) from the control device (1). 2. The assembly of claim 1, wherein said assembly comprises at least one electrically insulating element (8) mounted on the connection block (7) so as to reinforce the insulation between the electrical connection element (72) and said wall (4). 3. The assembly of claim 2, wherein the electrical connection device (5) maintains said sealing means (91). 4. The assembly of claim 2 or 3, wherein the sealing means (91) is attached to the electrically insulating member (8). An assembly according to claim 3, wherein said sealing means (91) is held between the electrically insulating member (8) and the connection block (7). 6. An assembly according to claim 5, wherein said electrically insulating element (8) comprises a housing intended to be traversed by said connection terminal (6) and provided with a shoulder (101), said sealing means (91). being located in the housing and held against the connection block (7) by said shoulder (101). The assembly of claim 6, wherein said shoulder (101) holding said sealing means (91) is beveled outwardly of the electrical connection device (5). An assembly according to any one of the preceding claims, wherein said assembly comprises a plurality of sealing means (91), said sealing means (91) being mechanically interconnected. 9. The assembly of claim 2, wherein the sealing means (91) is intended to electrically isolate the connection terminal (6) and the wall (4). 10. The assembly of claim 9, wherein a first portion of the sealing means (91) extends longitudinally in a direction parallel to an extension direction of the connection terminal (6). 11. The assembly of claim 9 or 10, wherein said sealing means (91) is in contact with the electrical insulating element (8) and intended to be in contact with said connection terminal (6) and / or the wall (4). 12. Assembly according to one of claims 9 to 11, wherein a second portion of the sealing means (91) is configured to be located between the electrical insulation member (8) and said wall (4). 13. Assembly according to one of claims 9 to 12, wherein said sealing means (91) is intended to be bonded to the wall (4) and / or the electrical terminal (6). 14. Assembly according to one of claims 9 to 13, wherein said electrically insulating element (8) comprises a housing intended to be traversed by said connection terminal (6), said sealing means (91) being located at inside the dwelling. 15. Compressor (9) comprising an assembly according to any one of the preceding claims.