EP3167193A1

EP3167193A1 - Electric compressor plate and electric compressor comprising such a plate

Info

Publication number: EP3167193A1
Application number: EP15756986.4A
Authority: EP
Inventors: Augustin Bellet; Xin Xu
Original assignee: Valeo Japan Co Ltd
Current assignee: Valeo Japan Co Ltd
Priority date: 2014-07-07
Filing date: 2015-07-07
Publication date: 2017-05-17
Also published as: FR3023328B1; FR3023328A1; WO2016005890A1

Abstract

Plate (4) of an electric compressor for refrigerant fluid, which plate is intended to separate an electric motor of the electric compressor from an electric control device of said electric motor, said plate (4) comprising an end wall (5) and a means (13) for receiving a transmission shaft of the motor starting from said end wall (5) of the plate (4), said plate (4) defining a passage (40) for the circulation of said refrigerant fluid and intended to guide the refrigerant fluid over at least one turn around the receiving means (13) and in a single sense (D).

Description

Plate of an electric compressor and electric compressor comprising such a plate

The invention relates to a plate of an electric refrigerant compressor and said electric compressor comprising the plate. It will find in particular its applications in 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. Moreover, for reasons of overall efficiency, the preferred solution for driving a compressor in a hybrid vehicle or electric is by feeding an electric motor driving the compressor rather than a belt output of the electric machine.

Such electric compressors comprise a compression mechanism driven by the electric motor, and a control device of the electric motor. The control device is located in a separate compartment of the electric motor by at least one partition wall on which is mounted the control device. The engine is located in another compartment.

Due to the electrical components of the control device, the latter can generate a large amount of heat in operation. It is then necessary to cool it.

It is known for this to use the coolant circulating in the engine compartment to cool the latter. An existing solution is to position the refrigerant inlet in the compartment of the electric motor between the partition wall and the electric motor so that entering the compartment of the electric motor, the refrigerant circulates near the element of support before being sucked to the compression mechanism. However, this solution implies that a too small amount of coolant circulates in contact with the plate so that the cooling of the plate is unsatisfactory. It is known to improve this cooling, to have the cooling fins on the separation plate. However, this complicates the manufacture of such a plate and also has the disadvantage of significantly increasing the pressure loss of the fluid, which deteriorates the thermal efficiency of the cooling.

The invention aims to improve the situation and thus concerns a plate of an electric refrigerant compressor, intended to separate an electric motor from the electric compressor of an electric control device of said electric motor, said plate comprising a bottom wall and means for receiving an engine transmission shaft originating from said bottom wall of the plate, characterized in that said plate defines a circulation channel of said refrigerant fluid for guiding the refrigerant on less than one turn around the receiving means and in one direction.

Thus, thanks to the invention, the plate and in particular its circulation channel is arranged to guide the refrigerant fluid so as to ensure good cooling of the plate while limiting the fluid pressure losses.

In one embodiment of the invention, the plate defines a refrigerant circulation channel for guiding the refrigerant over less than one turn around the receiving means and in a single direction to a zone to be cooled. . According to various embodiments of the invention, which may be taken together or separately:

the plate comprises bosses extending transversely to the bottom wall and intended to receive means for fixing the plate to a box configured to receive said electric motor, said bosses being interconnected by a wall defining an edge; said circulation channel;

the bosses extend perpendicularly to the bottom wall;

said wall remains concave between said bosses;

said wall is in an arc of a circle between said bosses;

the plate comprises three bosses interconnected by said wall;

said wall is formed in continuity of material from the remainder of said plate;

said plate comprises a partition intended to guide the fluid towards said channel when it comes into contact with the plate;

said partition is formed in continuity of material from the remainder of said plate;

the depth of the channel increases according to the direction of flow of the fluid in the channel;

said partition limits the passage of the refrigerant by forcing it to pass through the inlet of said channel;

said partition forms a cavity penetrating into an engine compartment; The invention also relates to an electric compressor comprising a plate as defined above.

Advantageously, the housing comprises an opening through which the fluid enters the housing at an inlet manifold.

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

- Figure 1 is a view of a compressor comprising a plate according to the invention, illustrated according to a diametral cutting plane.

- Figure 2 is an elevational view of the plate of Figure 1.

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

FIG. 1 illustrates an electric compressor 9 comprising a plate 4 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 an integrally circular periphery stator 2A and a rotor 2B integral with a transmission shaft 21 of the motor extending longitudinally along an axis H as shown in FIG. which turns to drive the compressor. The plate 4 comprises a receiving means 13 of the transmission shaft 21 of the engine originating from a bottom wall 5 of the plate 4. Said receiving means 13 here comprises a bearing-shaped housing which can accommodate a roller bearing. balls or equivalent.

The compression mechanism 3 comprises fixed parts and moving parts, the latter being set in rotation by the shaft 21 of the electric motor 2. The compression mechanism 3 is of the spiral compression type (Scroll in English) or of the type vane or 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 at least one housing 7 defining a cavity 17 accommodating said electric motor 2. This housing 7 is, for example, a piece of aluminum or aluminum alloy, of hollow circular shape comprising a peripheral envelope which delimits an internal volume. This housing 7 comprises at least one engine compartment 20 corresponding to said cavity 17 and in which is mounted the electric motor. In the example shown, the housing 7 also comprises at least one control compartment 10 in which the control device 1 is mounted. These compartments are separate volumes separated from each other by said plate 4. The plate 4 thus separates the control device 1 from said cavity 17 and the electric motor 2 and receives the control device 1. It forms with the housing 7, the engine compartment 20. The plate 4 may be part of the housing 7, or be assembled to the latter, for example at the time of mounting the control device 1 on the housing 7. The plate here comprises a peripheral wall 6, transverse to the bottom wall 5 so that the plate 4 defines an end housing which can be described as sub-housing here forming the control compartment 10. For example, the housing can be rendered external airtight via a closure lid, the sub-housing and the lid cooperating with each other via a suitable sealing means arranged between these two elements.

The housing 7 of the engine compartment 20 comprises an opening 8 allowing a refrigerant to enter the housing 7. The opening 8 is here located right of the electric motor 2, that is to say that it is located at planes perpendicular to the shaft of the electric motor 2 passing through said motor shaft.

The compression mechanism 3, located on the left of the figure, is located at a first longitudinal side 1 1 of the engine compartment 20. The control device 1, located on the right of FIG. 1, is located at a second longitudinal side 12 of the electric motor 2, opposite the first longitudinal side 1 1 with respect to the electric motor 2. It is understood here that the control compartment 10 is located at the second side 12 of the engine compartment 20.

In this example, reference is made to the housing 7, the sub-housing forming the control compartment 10 in which is housed the control device 1 at the second side 12 of the engine compartment 20, and a sub-housing forming a compression compartment 30 in which is housed the compression mechanism 3 at the first side 1 1 of the electric motor. In other words, the engine compartment 20 is interposed between the control compartment 10 and the compression compartment 30. It will therefore be understood that these compartments may be delimited by a single peripheral part which forms a single housing, provided with a partition, or, for example, by separate sub-housings dedicated to each compartment and assembled to each other.

The plate 4 can thus be part of the housing 7, the sub-housing forming the control compartment 10 or be connected between the housing 7 and the sub-housing forming the control compartment 10.

In operation, the refrigerant or mixture consisting of a coolant mixed with a lubricant, enters the engine compartment 20 through the opening 8. The refrigerant fluid is a subcritical fluid such as for example the R134a but it can also be a supercritical refrigerant such as 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 in 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.

As explained above, the engine compartment 20 is separated from the control compartment 10 by the plate 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 compartment control device 10 for protecting the control device 1 which comprises elements having high electrical potentials.

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 by an electrical connection device mounted at the interface between the engine compartment 20 and the control compartment 10, for example through the bottom wall 5 of the plate 4. The electrical components of the control device 1 release a large amount of heat and it is therefore necessary to cool them, in particular by cooling the bottom wall 5 of the plate 4. To do this, said plate 4 defines a channel 40 for circulation of the refrigerant fluid for guiding the refrigerant in a plane parallel to said bottom wall 5 of the plate 4, on less than one turn around the receiving means 13 and in the same direction D. The fluid is thus guided to a zone predetermined 47 of the bottom wall 5 against which are arranged power elements of the control device that require increased cooling. It is understood that the fluid comes into contact with the bottom wall 5 of the plate 4 at the arrow referenced 35 in Figure 2 and is guided around the receiving means 13, on less than one turn and in the one-way D. The channel 40 thus allows the fluid to circulate on almost the entire plate 4 so as to cool, by rotating around the receiving means 13, without causing significant pressure losses since the entire fluid will go to through the engine compartment and to the compression compartment before having made a complete revolution around the receiving means 13.

Thus, the fluid enters the casing 7 through the opening 8, is guided to rotate around the receiving means 13 by the channel 40 and passes through the engine to reach the compressor it passes through in turn.

Channel 40 is designed in such a way that its depth evolves between a lower depth located at an upstream zone with respect to the direction of flow of the fluid and an increased depth at a downstream zone located near said predetermined zone 47 requiring specific cooling. Thus the movement of the refrigerant fluid tends towards a direction of the coolant opposite the engine and the compression device.

The plate 4 here comprises a proximal collector 50 and a distal collector 52 of the fluid between which the channel 40 extends. At said collectors 50, 52, the fluid passage section is wider and the guiding effect is reduced compared to that offered by the channel 40.

The plate 4 comprises for example a partition 46 guiding the fluid at the outlet of the opening 8 in the direction of the direction D. The partition 46 at least partially defines the proximal collector 52. The partition 46 also blocks the fluid when has rotated around the receiving means so that it performs less than one revolution around the receiving means 13.

In addition, the partition 46 limits the passage of the refrigerant through the area of the electrical terminal and the engine power connector, forcing it to pass through the entrance of the channel 40.

In a particular embodiment, the partition 46 may also form a cavity penetrating into the engine compartment 20. The cavity 46 is then intended primarily to receive components, such as capacity, which allows them to have optimal cooling.

The plate 4 comprises bosses 41, here three in number, extending transversely to the bottom wall 5, in particular perpendicular, and intended to receive fastening means 42 of the plate on the housing 7. The bosses 41 are for example located along the peripheral wall 6. They extend inwardly of the compressor 9, that is to say towards the inside of the housing 7. The bosses 41 are interconnected by a wall 45 defining an edge of said circulation channel 40. The wall 45 remains concave between said bosses 41. It is also here in an arc between said bosses 41. For example, it is substantially parallel to the peripheral wall 6. The channel 40 thus makes it possible to avoid fluid foldback zones, which would create zones of turbulence opposing the direction of flow D of the fluid. Such a channel 40 thus allows a substantial reduction in the pressure drop. The opposite edge of the channel 40 is here defined by the landing of the receiving means 13.

It should be noted that the channel 40 reduces the pressure losses relatively relatively by allowing a large portion of refrigerant to circulate with a relatively small number, or even zero, of obstacles up to said predetermined zone. As a result, it reduces the portion of refrigerant that is directly sucked by the compression mechanism.

In this way, the refrigerant which enters the channel 40 through the opening 8 is guided by the partition 46 to the channel 40 and then by the wall 45 around the receiving means 13 in the direction of the arrow referenced D, which is identical to the direction of rotation of the rotor of the electric motor, on less of a turn. The refrigerating fluid arriving in the channel 40 is in fact sucked by the compression mechanism and, taking into account the conformation of the channel 40, guided along the bottom wall 5 of the plate 4.

The bosses 41, the partition 46 and / or the wall 45 are for example formed from the peripheral wall 6 and / or the bottom wall 5 of the plate 4, that is to say, in continuity of material the rest of the plate 4 which can be obtained by forging or molding.

The channel 40 further allows a maximum of fluid to pass through the engine and not outside thereof, that is to say outside the stator. The engine cooling is thus improved. It is in particular thanks to the extra thickness of material created by the bosses 41 and the wall 45 that the channel 40 guides the fluid in priority towards the center of the motor and not towards its periphery.

The plate of the invention thus provides a solution to the optimization of cooling without degrading the overall efficiency of the compressor

Claims

claims

1. Plate (4) of an electric refrigerant compressor (9) for separating an electric motor (2) from the electric compressor (9) of an electric control device (1) of said electric motor (2), said plate (4) comprising a bottom wall (5) and a receiving means (13) of a transmission shaft (21) of the motor (2) originating from the bottom wall (5) of the plate (4), characterized in that said plate (4) defines a channel (40) for circulating said coolant for guiding the coolant on less than one turn around the receiving means (13) and in a single direction (D).

2. Plate (4) according to claim 1, wherein the plate (4) comprises bosses (41) extending transversely to the bottom wall (5) and intended to receive fastening means (42) of the plate (4) has a housing (7) configured to receive said electric motor (2), said bosses (41) being interconnected by a wall (45) defining an edge of said circulation channel (40).

3. Plate according to claim 2, wherein said wall (45) remains concave between said bosses (41).

4. Plate according to claim 2 or 3, wherein said wall (45) is in an arc between said bosses (41).

5. Plate (4) according to one of claims 2 to 4, wherein the plate (4) comprises three bosses (41) interconnected by said wall (45).

6. Plate (4) according to one of claims 2 to 5, wherein said wall (45) is formed in continuous material from the rest of said plate (4).

7. Plate (4) according to any one of the preceding claims, wherein said plate (4) comprises a partition (46) for guiding the fluid to said channel (40) at its entry into contact with the plate (4). .

8. Plate (4) according to claim 7, wherein said partition (46) is formed in continuity material from the rest of said plate (4).

9. Electric compressor (9) comprising a plate (4) according to any one of the preceding claims.

The electric compressor (9) according to claim 9, wherein the housing (7) comprises an opening (8) through which fluid enters the housing (7) at an inlet manifold.