EP2622222B1 - Electric terminal device for an electric compressor - Google Patents

Description

The technical sector of the present invention is that of compressors constituting a refrigerant circuit fitted to a motor vehicle.

The refrigerant fluid is conventionally circulated inside an air conditioning circuit via a compressor. In vehicles equipped with an internal combustion engine, this compressor is mechanical type because its rotation is driven by means of a pulley connected to the internal combustion engine by a belt.

The number of hybrid vehicles, that is to say with an internal combustion engine coupled to an electric motor, or all electric, that is to say exclusively powered by an electric motor, is constantly increasing by the fact of 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.

However, the transition between the use of an internal combustion engine and the use of an electric propulsion motor of the vehicle is not instantaneous. Indeed, 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 electric compressor.

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 is different from the lubricant conventionally used for a mechanical compressor, the latter losing its dielectric power when it is mixed with the refrigerant.

In addition to the fact that the cost of this dielectric lubricant is higher than the conventional lubricant used for a mechanical compressor, such a situation requires the manufacturer of this vehicle model to manage two types of lubricant at the level of the vehicle production line. .

A first disadvantage of this situation lies in the fact that this management of two lubricants is particularly cumbersome to implement and increases the possibility of making errors in the production line.

International patent application WO2009 / 157275 discloses an electrical connection device between an electric motor of a compressor and its control device.

It is also known from the document EP2039932 a compressor comprising a device for electrically connecting the connection elements of the behavior housing the electric motor.

The electrical connection device proposed in this application presents a solution where the electrical connection between the conductor supplying the electric motor and the driver from the control device is provided inside a compartment of the compressor receiving the control device. It is therefore understood that the assembly of the compressor requires to pass through the compartment receiving the control device to electrically connect the motor to its control device.

This represents a major disadvantage because such an organization prevents a complete and separate manufacture of the part of the compressor containing the control device. Indeed, the electrical connection at the bottom of the compartment, it is then necessary to secure the electrical connection device before installing the printed circuit boards constituting the control device. Thus, it is not possible to separate the assembly of the control device in the dedicated part of the compressor from the rest of the other assembly operations of the compressor, including the mounting of the electric motor.

Moreover, this solution has the disadvantage of having a large amount of parts to assemble to ensure the electrical and mechanical connection.

The object of the present invention is therefore to solve the drawbacks described above mainly by electrically connecting an electrical harness from the control device with an electric harness supplying the engine on the side of the compressor compartment which receives the electric motor while guaranteeing no arcing will occur between the fluid and one of the terminals.

The subject of the invention is therefore a compressor comprising a first compartment housing an electric motor and separated by a wall of a second compartment housing an electric motor control device connected to the motor by an electrical connection device, the connecting device comprising a plurality of terminals connected to a plurality of elements of isolated connection of the first compartment by an innovative insulating means in that it comprises a fixing means between the insulating means and the wall, the fixing means being operable from the first compartment characterized in that the wall comprises a recess and a shoulder, the latter being intended to receive an outgrowth emerging laterally from a body of said insulating means.

It is therefore understood here that accessibility to the fastening means occurs exclusively by the compressor compartment which contains the electric motor. The insulating means provides electrical insulation to avoid any electric arc between a terminal and / or a connection element and the fluid present in the first compartment. A polyalkylene glycol type lubricant can thus be used without risk. Such a fixing means is for example at least one screw engaged in a tapping formed in a blind hole in the thickness of the wall located between the first compartment and the second compartment.

The securing action of the insulation means on the wall does not use an element that extends into the second compartment.

The insulating means extends against a face of the wall which faces the first compartment.

According to a first characteristic of the invention, the plurality of terminals is electrically connected to the control device while the plurality of connection elements is electrically connected to the electric motor.

According to a second characteristic of the invention, the isolation means provides electrical insulation and a seal against the fluid present in the first compartment.

According to another characteristic of the invention, the isolation means takes the form of a cover covering the plurality of terminals and the plurality of connection elements.

According to another characteristic of the invention, the cover comprises a housing filled with an insulating gel and in which the plurality of terminals and the plurality of connection elements extend.

According to yet another characteristic of the invention, the wall provides a sealing between the first compartment and the second compartment. The passage hole of the electrical harness between the control device and the electric motor is thus the only opening between the first compartment and the second compartment.

Advantageously, the fixing means comprises at least one screw engaged with a tapping made in the wall. The tapping is advantageously blind in the thickness of the wall.

Advantageously, the electrical connection device comprises a base through which the plurality of terminals extends. The angular positioning of the base is provided beforehand during the assembly of the control device in the second compartment. This base is held in position by the fact that the terminals are mechanically and electrically connected, for example by welding, to rigid electrical connection elements originating or constituting the control device.

The base has a cylindrical section, for example circular, which facilitates the integration of the base in the wall. The seal can be achieved by means of easy to use circular seal to manufacture and install. Note that in such a case, the isolation means comprises a cylindrical body, preferably circular outer diameter identical to the outer diameter of the base.

According to a first characteristic of the invention, the wall comprises a recess where the base is housed in a sealed manner. The dimensional impact of the connection device on the compressor is thus reduced by juxtaposing the thickness of the wall and the thickness of the connecting device.

According to a second characteristic of the invention, the insulating means is housed in the recess, advantageously in a sealed manner.

According to another characteristic of the invention, the insulating means comprises at least one protrusion arranged to cooperate with the fixing means. This arrangement is implemented by a hole in the protrusion which allows the passage of the fixing means.

According to another characteristic of the invention, the protuberance is formed laterally with respect to a body constituting the insulation means, advantageously the lid.

According to yet another characteristic of the invention, the wall comprises a peripheral shoulder to the recess and in which the protrusion is housed. The dimensional impact of the connection device on the compressor is further reduced.

Finally, the isolation means comprises means for retaining at least one of the connection elements. This structure facilitates the mounting of the isolation means by providing a pre-positioning of the connection elements with respect to the terminals at the time of mounting the insulation means on the base. Fixing the insulation means on the wall also provides a function of pressurizing a seal between the base and the recess.

A first advantage resulting from the possibility of ensuring the electrical connection between the motor and its control device on the side of the housing that receives the compressor lies in the possibility of ensuring the assembly and control of a first subset compressor having the control device independently of the assembly of the rest of the compressor. Thus, this subset forms a semi-finished part on which no additional intervention is necessary.

Another advantage lies in the small number of components constituting the connecting device which makes it possible to ensure the mechanical fixing as well as the electrical connection in a single step of fixing the insulating means on the wall of the compressor which separates the compartment from receiving the control device of the receiving compartment of the electric motor.

• la figure 1 est une vue schématique d'un compresseur électrique selon l'invention,
• la figure 2 est une vue de face de la paroi du compresseur équipée du dispositif de raccordement,
• la figure 3 est une vue en coupe du dispositif de raccordement selon une première variante de réalisation,
• la figure 4 est une vue en coupe du dispositif de raccordement selon une deuxième variante de réalisation.

Other characteristics, details and advantages of the invention will emerge more clearly on reading the description given below as an indication in relation to drawings in which:

• the figure 1 is a schematic view of an electric compressor according to the invention,
• the figure 2 is a front view of the wall of the compressor equipped with the connecting device,
• the figure 3 is a sectional view of the connection device according to a first embodiment variant,
• the figure 4 is a sectional view of the connecting device according to a second embodiment.

It should be noted that the figures show the invention in detail for implement the invention, said figures can of course be used to better define the invention where appropriate.

The figure 1 illustrates a schematic view of an electric compressor according to the invention and its main components. The compressor 1 is an electric compressor in that it incorporates an electric motor 6 which drives a compression mechanism 7. This compression mechanism 7 is of the type of compression screw (Scroll in English) or the pallet type or piston type, these examples being given for illustrative purposes without limiting the scope of the invention.

The compressor 1 is delimited vis-à-vis its external environment by a housing 2. This housing 2 is a piece of aluminum or aluminum alloy, hollow circular shape comprising a peripheral wall which defines an internal volume. This housing comprises at least three compartments which take the form of cavity or housing formed inside the housing 2. These compartments are separate volumes separated from each other by at least one wall. It will therefore 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 to each other to form the compressor. In other words, the compressor may for example consist of a main housing, forming a first compartment 3, which houses the electric motor and on which is reported at one end, a first separate secondary housing which delimits a second compartment 4, and at a second end, a second separate secondary housing forming a third compartment 5.

The first compartment 3 is provided interposed between the second compartment 4 and the third compartment 5. The first compartment 3 houses the electric motor 6 which comprises a stator and a rotor, the stator consisting among others of a plurality of coils. In operation, a fluid or mixture consisting of a refrigerant mixed with a lubricant enters the first compartment and circulates around and in the electric motor 6. The coolant is a subcritical fluid such as for example the R134a but it can also it is a supercritical refrigerant fluid such as, for example, carbon dioxide known under the name R744. The lubricant is for example a compound Polyalkylene glycol type.

The fluid circulates in the first compartment 3 and then in the third compartment 5 in which there is a compression mechanism 7. This ensures the increase in pressure and temperature necessary for the operation of a thermodynamic loop comprising the compressor according to the invention . This compression mechanism is driven by means of a shaft 9 connected to the rotor of the electric motor 6.

The compression mechanism 7 comprises fixed parts and moving parts, the latter being rotated by the shaft 9 which extends along a longitudinal axis of the compressor 1. This shaft 9 therefore extends in the first and third compartment, substantially in the center of the housing 2.

The first compartment 3 is separated from the second compartment 4 by a wall 8 which prevents the penetration of the fluid into the second compartment. It is thus understood that the fluid present in the first compartment 3 does not circulate in the second compartment 4.

This second compartment 4 defines a reception zone of a control circuit 10 of the electric motor. This control circuit 10 is notably an inverter (inverter in English) transforming a stream of continuous form coming from the vehicle into a stream of sinusoidal shape supplying the electric motor 6 in a perfectly sealed manner between the first compartment 3 and the second compartment 4 to withstand all possible pressure and temperature deviations during the life of the compressor.

The control device 10 supplies electrical energy to the electric motor 6. Since these components are in two separate compartments, it is necessary to allow the passage of a power supply beam which connects the control device 10 to the motor 6. .

To do this, an electrical connection device 11 provides an electrical connection between a plurality of terminals 12 and a plurality of connection elements 13. By plurality is meant in particular three terminals and three connection elements.

Each terminal 12 electrically connects the control device 10 to the connection elements 13 of the connection device 11. Each terminal 12 opens into the connection device and can for example be connected directly or via at least one intermediate conductor to the control device.

Each connection 13 opens into the connection device and can be connected to a coil of the electric motor by a cable or more generally an electrical conductor, directly or indirectly.

Finally, note that each connection element is removable from its terminal. It is therefore a reversible mechanical connection ensuring the passage of electric current.

The figure 2 shows in more detail the structure of the connecting device 11. This device is here mounted on the wall 8 defining the first compartment of the second compartment and that view of the first compartment.

The wall 8 comprises a through hole inside which the connecting device 11 is installed. The latter comprises an electrical isolation means 14 between the terminals and / or the connection elements and the fluid present in the first compartment of the engine. This insulating means 14 also ensures a seal against a fluid present in the first compartment 1 to prevent it from circulating from the first compartment 3 to the second compartment 4. This sealing is provided by collaboration of the means insulation 14 with a base 20 which will be described below.

This isolation means 14 thus fulfills at least two functions: providing electrical isolation between the fluid and the terminals and / or the connection elements, and preventing any fluid flow from the first compartment to the second compartment.

This isolation means 14 covers the plurality of terminals 12 as well as the plurality of connection elements 13, the latter being each for example crimped on a flexible cable 22 consisting of a conductive core 15 trapped in an electrically insulating sheath 16, for example plastic. Sealing is also practiced between the cables 22 and the insulating means 14 by virtue of the use of a seal 37.

The insulation means 14 comprises a body 17 of particular circular shape. At least one protrusion 18 emerges, for example, laterally from the body 17 so as to ensure the fixing of the insulating means 14 on the wall 8.

The protrusion 18 forms a flat parallel to the plane in which the wall 8 and comprises for example a hole allowing the passage of the fastening means of the insulating means 14 on the wall 8 of the compressor.

In the example of the figure 2 the body 17 comprises two protuberances 18 which extend in angularly spaced directions of 170 °.

Of course, the description above forms an embodiment, but it is clear that all other forms of the insulation means are covered by the invention as long as it can be secured to the wall of the compressor and ensure the insulation. electrical connection between at least one terminal or connecting element and the fluid present in the first compartment.

Finally, it will be noted that the wall 8 comprises a joint plane 19 which extends at the periphery of this wall. This joint plane seals between the first secondary housing constituting the second compartment and the main housing constituting the first compartment. The connecting device 11 is installed immediately adjacent to this joint plane 19.

The figure 3 illustrates a first embodiment of the connecting device according to a section AA shown on the figure 2 .

The upper part of the figure 3 in which extends the cable 22 forms the first compartment 3 while the lower part of the figure 3 in which extends a terminal 12 forms the second compartment 4.

The connecting device 11 comprises a base 20 which extends in a plane parallel to the plane of the wall 8. The latter comprises a recess 21 formed in the thickness of the wall 8 around the through hole.

The base 20 is installed inside the recess 21 and bears against a shoulder delimiting the hole. The base, which may for example be metallic, comprises on its outer periphery a clearance 23 which receives a sealing means 24 whose function is to guarantee the seal between the first compartment 3 and the second compartment 4. This means of sealing 24 takes for example the form of an O-ring, a flat gasket or a lip seal.

The base 20 is traversed from one side by the plurality of terminals 12 and the latter are secured to the base by an electrically insulating pad 25, for example made of glass. In addition, an electrically insulating cover 26, for example made of ceramic, is threaded onto each terminal 12 so as to prevent any electric arc between the terminal and the edge of the wall 8 immediately adjacent to the terminal.

At the periphery of the recess 21 is formed a shoulder 27 whose function is to receive the protrusion 18. The insulation means 14 takes for example the form of a cover covering the plurality of terminals 12 and the plurality of Connecting elements 13. This insulating means 14 takes the form of a bowl delimiting an internal volume where the connection between each terminal 12 and each connection element 13 is made. In the assembled position, the protrusion 18 bears against the bottom of the shoulder 27 and the body 17 bears against one of the faces of the base 20.

The insulating means 14 may be formed of a single unitary molded piece of plastic, for example a thermoplastic polyester, but it may also be formed of an assembly of separate pieces. In the case of figure 3 , the insulating means 14 comprises a closure cap 36 which obstructs the internal volume in which each terminal 12 and each connection element 13 extend. This cover is made integral with the body 17 by gluing or by a linking clipping means hood 36 to the body 17.

Fastening means 28 is provided for securing or securing the insulating means 14, for example by means of the protrusion 18, on a face 29 of the wall 18 facing the first compartment 3. This fixing means 28 can be reversible or irreversible but must however provide a reliable mechanical resistance to prevent movement of the connection element 13 relative to the terminal concerned. For example, it may be a screw 30 whose thread is engaged on a thread 31 formed in the thickness of the wall 8, this thread being for example made in a blind hole in the wall thickness 8.

The fixing means 28 is operable, in particular exclusively operable, from the first compartment 3. It is understood here that the mounting of this fastening means is carried out through the first compartment 3. For example, the screw 30 is equipped with a 32 hexagonal head, recess or split which extends into the first compartment 3. It is not necessary to intervene in the second compartment to secure the insulation means on the wall.

Fixing the insulating means 14 by means of the fixing means 28 ensures the mechanical holding of the connecting device 11. This fixing also ensures the electrical connection between each terminal 12 and each connection element 13.

Optionally, the insulating means 14 comprises a sealing device 33 installed at the outer periphery of the body 17 so as to come into contact with the inner wall of the recess 21. This sealing means 33 takes, for example the shape of an O-ring, a flat gasket or a lip seal. It is thus understood that the insulating means 14 is housed in the recess 21 in a sealed manner, that is to say to prevent the fluid (coolant mixed with the lubricant) coming into contact with the terminals 12 and / or connection elements 13.

The insulating means 14 further comprises a means for retaining the connecting elements 13. This is for example a shape complementary to the shape of the connection element so as to ensure a mechanical holding of the element in the internal volume of the lid forming the insulating means 14. It may also be for example a clip molded on the inner wall of the cover and which mechanically retains the cable and / or the connection element concerned. .

The figure 4 illustrates an alternative embodiment of the figure 3 and we will refer to the description of the figure 3 for identical elements.

The connection device 11 of the figure 4 differs from that shown on the figure 3 in that the insulating means 14 comprises a housing 34 filled with an insulating gel 35. In this situation, the body 17 has an opening which opens out on the first compartment 3 and through which the insulating gel 35 can be introduced into the housing 34. The gel is for example a compound comprising epoxy.

This second embodiment has the advantage of making each terminal and each connection element apparent once the connection device 11 is mounted against the wall 8. The contact between the terminal and the connection device can thus be checked visually. The electrically insulating gel 35 can then be introduced into the housing so as to surround each connection and ensure that the fluid will not be in contact with the electrical connection.

Claims (13)

1. Compressor (1) comprising a first compartment (3) housing an electric motor (6) and separated by a wall (8) from a second compartment (4) housing a control device (10) for the electric motor linked to the motor (6) by an electrical connection device (11), the electrical connection device (11) comprising a plurality of terminals (12) connected to a plurality of connection elements (13) insulated from the first compartment (3) by an insulation means (14), comprising a fixing means (28) between the insulation means (14) and the wall (8), the fixing means (28) being operable from the first compartment (3), characterized in that the wall (8) comprises a void (21) and a shoulder (27), the latter being intended to receive a protuberance (18) emerging laterally from a body (17) of said insulation means (14).
2. Compressor according to Claim 1, in which the plurality of terminals (12) is electrically connected to the control device (10) whereas the plurality of connection elements (13) is electrically connected to the electric motor (6).
3. Compressor according to one of Claims 1 or 2, in which the insulation means (14) ensures electrical insulation and seal-tightness with respect to a fluid present in the first compartment (3).
4. Compressor according to any one of Claims 1 to 3, in which the insulation means (14) takes the form of a cover covering the plurality of terminals (12) and the plurality of connection elements (13).
5. Compressor according to Claim 4, in which the cover comprises a housing (34) filled with an insulating gel (35) and into which extend the plurality of terminals (12) and the plurality of connection elements (13).
6. Compressor according to any one of the preceding claims, in which the wall (8) ensures a seal-tightness between the first compartment (3) and the second compartment (4).
7. Compressor according to any one of the preceding claims, in which the electrical connection device (11) comprises a base (20) through which the plurality of terminals (12) extends.
8. Compressor according to Claim 7, in which the wall (8) comprises a void (21) where the base (20) is housed in a seal-tight manner.
9. Compressor according to Claim 8, in which the insulation means (14) is housed in the void (21).
10. Compressor according to any one of the preceding claims, in which the insulation means (14) comprises at least one protuberance (18) arranged to cooperate with the fixing means (28).
11. Compressor according to Claim 10, in which the protuberance (18) is formed laterally relative to a body (17) forming the insulation means (14).
12. Compressor according to either one of Claims 8 and 9 combined with either one of Claims 10 or 11, in which the wall (8) comprises a shoulder (27) peripheral to the void (21) and in which the protuberance (18) is housed.
13. Compressor according to any one of the preceding claims, in which the insulation means (14) comprises a retaining means for at least one of the connection elements (13).

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