Patent Application
20130315720
The technical sector of the present invention is that of the housings for electrical compressors constituting a refrigerant circuit with which a motor vehicle is equipped.
A refrigerant is conventionally circulated inside an air conditioning circuit by means of a compressor. In the vehicles that are equipped with an internal combustion engine, this compressor is of mechanical type, because its rotation is operated by means of a pulley linked to the internal combustion engine by a belt.
The number of hybrid vehicles, that is to say vehicles with an internal combustion engine coupled to an electric motor, or all-electric vehicles, that is to say vehicles exclusively propelled by an electric motor, is constantly increasing because of the depletion of the fossil energies that are the basis of the fuel supplying the internal combustion engine with which the vehicles are equipped.
The mechanical energy usually supplied by the internal combustion engine is therefore less available, or totally unavailable in the case of all-electric vehicles.
Compressors driven by a dedicated electric motor do exist in the literature. The document FR2814783A1 discloses a compressor comprising an electric motor controlled by a control circuit. The latter is mounted on an outer surface of a wall of a refrigerant suction passage. Cooling fins are formed on the inner surface of the wall, in order to cool the control device.
A first drawback with this known solution lies in the limited effectiveness of the heat transfer between the wall and the refrigerant.
Another drawback lies in the bulk created by the cooling fins disclosed in this document. The latter necessarily result in an increase in a dimension of the compressor measured on the rotation axis thereof.
The aim of the present invention is therefore to resolve the drawbacks described above, mainly by a different organization of the structure of the dissipation device, as well as its integration in the housing, in particular in relation to the other shapes produced on the housing.
The subject of the invention is therefore a housing of an electrical compressor for a refrigerant circuit, comprising a wall suitable for delimiting a first volume of the compressor in which the refrigerant circulates relative to a second volume of the compressor into which a control device of the electric motor extends, a first face of the wall facing the second volume being configured to receive the control device while a second face of the wall facing the first volume comprises a heat dissipation means, characterized in that the heat dissipation means takes the form of a plurality of tubular elements originating from the second face. The plurality of tubular elements makes it possible to significantly increase the heat exchange surface by allowing the refrigerant to circulate along the second face and between the tubular elements, the latter acting as disrupters of the flow of the refrigerant to promote the heat exchange between the wall of the housing and the refrigerant.
According to a first feature of the invention, at least one tubular element is formed by a solid tube of circular section made of the same material as the wall. Advantageously, all the tubular elements are produced in the same format, for example that described above.
According to a second feature of the invention, at least one tubular element extends along an axis perpendicular to a first plane in which the second face of the wall is inscribed. Such an organization offers a benefit by virtue of the fact that the refrigerant sweeps over the wall in a direction parallel, or substantially parallel, to the plane in which the second face extends. The tubular elements are thus placed perpendicularly to the flow of refrigerant, so as to increase the heat exchange and the turbulence.
According to another feature of the invention, the housing can comprise a peripheral edge formed by a first portion which emerges from the second face of the wall and a second portion which emerges from the first face of the wall, a length of the tubular elements measured on the perpendicular axis being less than a length of the first portion, measured on this same axis from the second face. It will be understood here that the tubular elements do not extend beyond the outer bulk of the housing.
According to yet another feature of the invention, the housing may comprise a bushing suitable for receiving a rolling bearing, the bushing emerging from the second face of the wall.
In such a case, the bushing is terminated by an end which is inscribed in a second plane separated from the first plane in which the second face is inscribed. Depending on the configuration of the compressor motor, in particular of the motor shaft, this second plane may be at a distance from the first plane which is less than the length of the first portion of the peripheral edge; or, conversely, the second plane can be at a distance from the first plane which is greater than the length of the first portion of the peripheral edge.
Advantageously, the length of at least one tubular element is less than the distance which separates the second plane from the first plane, the length of the tubular element being measured between the plane in which the second face is inscribed and the free end of the tubular element concerned. It will be noted that all the tubular elements forming the dissipation means can follow such a rule.
Also advantageously, the plurality of tubular elements is distributed on the second face around the bushing.
According to an exemplary embodiment, the wall may comprise a through orifice suitable for receiving an electrical connector linking the control device to the electric motor.
The housing may comprise a flank formed on the periphery of the wall. Such a flank forms, for example, a radial extension which originates on the peripheral edge.
In such a situation, the flank may comprise a first through hole arranged to receive a high voltage electrical power supply connector and a second through hole arranged to receive an electrical signal connector.
The invention also targets a compressor for a refrigerant circuit comprising a unit formed by a compression mechanism coupled to an electric motor, in particular both incorporated in the compressor, said compressor comprising a housing incorporating any one of the features described above.
Such a compressor, called electrical compressor, may comprise a high voltage electrical power supply connector installed in a first hole passing through a flank of the housing, and an electrical signal connector installed in a second hole passing through said flank.
The compressor according to the invention may comprise a refrigerant inlet orifice arranged on the compressor so that the refrigerant circulates between the tubular elements, that is to say sweeping over an outer surface of the tubular element which extends along its axis. In such a case, the refrigerant is also in contact with the second face of the wall of the housing.
A prime advantage according to the invention lies in a significant increase in the heat exchange produced between the refrigerant and the wall, particularly by virtue of the fact that the latter can circulate between a multiplicity of tubular elements securely attached to the wall. This multiplicity of elements thus generates turbulence in the refrigerant which prevent a laminar flow, in favour of a turbulent flow of the refrigerant.
Another advantage lies in a reduction of the impact of the dissipation device according to the invention on the axial footprint of the compressor. The improved heat exchange makes it possible to reduce the size of the dissipation device, which simplifies its integration on the housing of the compressor.
Other features, details and advantages of the invention will emerge more clearly on reading the description given hereinbelow as an indication, together with the drawings in which:
It should be noted that the figures show the invention in detail for the implementation of the invention, said figures obviously being able to serve to better define the invention, if necessary.
The first volume of the compressor is delimited by a jacket, notably cylindrical, which encloses an electric motor linked to a compression mechanism. The second volume of the compressor receives a control device of the electric motor installed in the first volume, such a device being, for example, an inverter. The second volume is notably delimited by the housing 1 according to the invention and by a cover which caps the housing 1. The structure of the compressor will be detailed more with reference to
The housing 1 comprises a wall 2 located between the first volume and the second volume of the compressor. This wall 2 is provided with an edge 3 formed at the periphery of the wall 2. This peripheral edge 3 follows, for example, a circular form and surrounds the wall 2.
This wall 2 is delimited on one side by a first face which faces the second volume in which the control device of the electric motor is received. The wall 2 is also delimited by a second face 4, opposite to the first face relative to the substance of the wall 2. This second face 4 faces the first volume of the compressor, that is to say the volume in which the refrigerant compressed by this compressor circulates.
The first face is configured to receive the control device of the electric motor in as much as it comprises at least one area against which the control device can be applied, so as to transfer the calories from the control device to the wall 2, by contact against the first face of the wall.
According to the invention, the second face 4 is provided with a heat dissipation means 5, the function of which is to transfer to the refrigerant calories generated by the control device. This heat dissipation means 5 takes the form of a plurality of tubular elements 6 originating from the second face 4.
Such a tubular element is a part made of the same material as the wall 2 and which extends along an axis. The wall 4 and the tubular elements 6 are therefore produced in the same manufacturing step. Advantageously, the axis in which the tubular element 6 extends is orthogonal to a plane in which the second face 4 is inscribed, hereinafter called first plane.
The section of a tubular element 6, taken in a plane parallel to the first plane of the second wall 4, represents a percentage of between 0.05 and 0.5% of the total surface area of the second face 4. Such a percentage makes it possible to locate a large number of tubular elements 6 on the second face, which makes it possible to guarantee an increase in the exchange surface area while limiting the length of the tubular elements. Thus, a suitable footprint for the compressor, in its axial direction, is maintained. Preferably, the percentage is 0.14%.
According to an exemplary embodiment, a tubular element 6 is formed by a solid tube of circular section and made of the same material as the wall. Obviously, the invention covers the case where the tube is hollow at its centre, and any other form of section of this tube, for example triangular, square, rectangular or ovoid.
The wall 2, and more particularly the second face 4, extends in the first plane, the latter being substantially perpendicular to a longitudinal axis of the compressor, passing for example through its drive shaft situated between the electric motor and the compression mechanism. The peripheral edge 3 is circular, but it extends perpendicularly to the first plane. It thus extends beyond the first plane, on either side of the wall 2, which makes it possible to form a first cavity delimited by the first face and a first portion 7 of the peripheral edge 3, as well as a second cavity delimited by the second face 4 and a second portion 8 of the peripheral edge 3.
The plurality of tubular elements 6 is, for example, fully contained in this second cavity. The tubular elements 6 are distributed on the second face 4 so as to form a multiplicity of rows, for example orthogonal to one another.
A tubular element 6 is notably defined by its length, or extension the second cavity. This length is measured between the first plane in which the second face 4 is inscribed and the free end of the tubular element 6. Preferentially, the length of the tubular elements 6 is less than the length of the second portion 8 of the peripheral edge 3, measured between the first plane and a rim 9 terminating this second portion 8 in a direction perpendicular to the first plane.
On the wall 2, a bushing 10 is formed which is suitable for receiving a rolling bearing. Such a bushing 10 is formed by a circular tube portion made of the same material as the wall 2. This bushing 10 is installed at the centre of the housing 1 and it is arranged to house a rolling bearing which holds an end of the drive shaft linking the electric motor to the compression mechanism of the electrical compressor.
An outer face 11 of the bushing 10 joins the second face 4 by a peripheral fillet 12. Opposite this fillet, the bushing 10 is terminated by an end 13 which is inscribed in a second plane which is notably distinct from the first plane. Advantageously, all of the bushing 10 is contained in the second cavity. In other words, the second plane is at a distance from the first plane less than the distance which separates the first plane from the rim 9 edging the second portion 8 of the peripheral edge 3. However, the second plane could be at a distance from the first plane greater than the distance which separates the first plane from the rim 9 edging the second portion 8 of the peripheral edge 3. The position of the second plane relative to the second portion 8 of the peripheral edge 3 is dependent on the configuration of the drive shaft.
According to an exemplary embodiment, the tubular elements 6 have a length less than the distance which separates the end 13 of the bushing 10 relative to the first plane in which the second face 4 is inscribed.
The tubular elements 6 are distributed on the second face 4, around the bushing 10, preferentially around the fillet 12.
The housing 1 may also comprise screwing blocks 14 of which, in this exemplary embodiment, there are five. The latter are in contact with the second portion 8 of the peripheral edge 3 and are distributed according to identical angular segments. These screwing blocks 14 extend in a direction perpendicular to the first plane in which the second face 4 is inscribed, and extend beyond the rim 9, that is to say beyond the second portion 8 of the peripheral edge 3.
In the middle of the heat dissipation means 5, fastening blocks 15 are formed, the function of which is to receive means for fastening the control device against the first face. These fastening blocks 15 extend into the second cavity, in a direction perpendicular to the first plane. The length of these fastening blocks 15 is greater than the length of the tubular elements 6, but less than the distance which separates the rim 9 from the first plane in which the second face 4 extends. However, the fastening blocks 15 could have any other configuration. In practice, the length of the fastening blocks 15 depends on the fastening means used on the first face and on the thickness of the wall 2.
Through the wall 2, an orifice 16 is formed, for example of circular section, which passes through the wall 2 from side to side. This orifice 16 is arranged to receive an electrical connector which electrically links the control device to the electric motor of the compressor. This orifice 16 is edged by a groove 17 formed on the second face 4, in order to receive a sealing device between the electrical connector and the wall 2. Two through holes are also formed immediately around the orifice 16, so as to be able to install therein a screw for fastening the electrical connector to the wall 2.
The housing 1 may also comprise a flank 18 formed on the outer periphery of the wall 2. Such a flank 18 originates on the peripheral edge 3 and extends radially and outward from the housing 1. The first cavity which receives the control device of the electric motor can advantageously be edged by this flank 18, a part of this control device extending into a portion of the first cavity surrounded by the flank 18.
In order to electrically power the compressor, the housing 1 may comprise a first hole 19 which passes through the wall forming the flank 18. This hole has a section, for example, which is circular, and it is intended to receive a high voltage electrical power supply connector. The flank 18 may also be provided with a second through hole 20, the section of which is notably square or rectangular. This second hole 20 is configured to receive an electrical signal connector, specially dedicated to supplying compressor monitoring, control and/or diagnostic information.
The material used to manufacture the housing 1 detailed above, which comprises the wall 2 provided with its plurality of tubular elements 6, can, for example, be an aluminium or magnesium alloy. This housing is advantageously manufactured at least by a foundry operation.
At an outer periphery of the first housing 22, there is a device 31 for fastening the electrical compressor 21 onto the vehicle. The central housing 23 also comprises two fastening devices 31 formed on an outer face of this central housing 23.
At the end opposite to the first housing 22 relative to the central housing 23, the housing 1 according to the invention is securely attached to one end 30 of the central housing 23. The first cavity delimited by the first portion 7 of the peripheral edge 3 and by the flank 18 is closed by a cover 24 securely attached to the housing 1 by a multiplicity of secure attachment means. The first housing 22, the central housing 23 and the housing 1 are thus aligned in a longitudinal direction 27 of the electrical compressor 21.
The electrical compressor 21 comprises the high voltage electrical power supply connector, here referenced 25, installed in the first hole passing through the flank 18 of the housing 1. Although not visible in this figure, the same applies for the electrical signal connector installed in the second hole passing through said flank.
The first housing 22 also comprises an outlet orifice 28 through which the refrigerant leaves the electrical compressor 21, after having been compressed by the compression mechanism.
A refrigerant inlet orifice 29 is formed on the central housing 23, adjacent, possibly immediately adjacent, to the end 30 of the central housing. This inlet orifice 29 extends in a direction perpendicular to the longitudinal direction 27 of the electrical compressor 21. Such a positioning of the inlet orifice 29 guarantees that the tubular elements forming the heat dissipation means will be swept over at their ends and along their peripheries by the refrigerant which enters the electrical compressor 21.
| Number | Date | Country | Kind |
|---|---|---|---|
| 1254635 | May 2012 | FR | national |
