EP2932169A1

EP2932169A1 - Compressor unit and utility vehicle having a cooling machine comprising a compressor unit of said type

Info

Publication number: EP2932169A1
Application number: EP13811863.3A
Authority: EP
Inventors: Norbert Flacke
Original assignee: Schmitz Cargobull AG
Current assignee: Schmitz Cargobull AG
Priority date: 2012-12-13
Filing date: 2013-12-13
Publication date: 2015-10-21
Also published as: DE102012024362A1; WO2014091018A1

Abstract

The present invention relates to a compressor unit for compressing refrigerant, having an electric drive motor which has a motor housing (30) which encapsulates the drive motor (1) with respect to the environment (U), and having a compressor (2) which is driven by the drive motor (1) and which serves for compressing a refrigerant drawn in by the compressor (2) as a refrigerant intake flow (K), and to a utility vehicle having a cooling machine comprising a compressor unit of said type. The compressor unit according to the invention makes it possible to reliably maintain optimum operating temperatures, even during operation at extreme ambient temperatures, using simple means. The utility vehicle according to the invention ensures high operational reliability even at high ambient temperatures. This is achieved according to the invention in that at least one section of the motor housing (30) of the drive motor (1) is at least intermittently flowed around by at least one partial flow of the refrigerant intake flow (K).

Description

Compressor unit and commercial vehicle with a cooling unit comprising such a compressor unit

The invention relates to a compressor unit for

Compressing refrigerant and a commercial vehicle with a refrigeration machine comprising such a compressor unit.

In such chillers, a medium to be cooled is passed through a heat exchanger through which a refrigerant flows simultaneously in spatial separation, but in heat-conducting contact with the cooling medium. The

Refrigerant expands in an endothermic reaction in the heat exchanger (evaporator), thereby removing heat from the medium to be cooled. The emerging from the evaporator heat exchanger refrigerant is from the

Compressor unit sucked in a suction, again compressed and in the other heat exchanger

(Condenser) ejected, where it liquefies to then, usually via a throttle, to be returned to the evaporator heat exchanger.

Chillers with compressors for compacting

Refrigerants are used today in many areas of daily life. For example, the air conditioning of passenger areas in vehicles or residential or commercial premises, as well as cooling in the supermarket, industrial and marine sectors, or even in the field of what is known as "transport refrigeration".

"Transport refrigeration" is needed when transporting temperature-sensitive goods from the producer to the processor, trader or end consumer. For this

Transport tasks are widely used commercial vehicles with thermally insulated structures, each equipped with a chiller to keep the stored in the construction space enclosed cargo during transport at a predetermined temperature.

A transport refrigerating machine suitable for this purpose is known from EP 1 046 543 B1. This exemplified for a variety of refrigerators designed machine is designed so that it can be mounted as a separate unit to the respective commercial vehicle. A special feature over other known, based on similar concepts Transportkühleinrichtungen is that in the EP 1 046 543 B1

known machine, the compressor is driven by an electric drive motor. The electrical energy to drive the engine is from a likewise in the

Chiller built-in combustion engine generator combination provided, which can be operated in each case in a stationary, performance-optimized operating point. Compressor and drive motor form in the known refrigerating machine, a compressor unit, which is complete by means of a drive motor and compressor housing together fully or semi-hermetically sealed to the environment. Characteristics of such full or

semi-hermetically sealed compressor units is that the drive motor and compressor have a common shaft and no special sealing of the shaft of the Compressor against leakage of refrigerant fluid into the environment or the drive motor is required, as by the hermetic shielding of compressor and

Drive motor is reliably prevented that refrigerant fluid enters the environment and is removed from the refrigeration cycle. At the same time can be at a common hermetic

Encapsulation of drive motor and compressor, the refrigerant fluid can be used to cool the drive motor.

From DE 10 2010 022 993 A1 a based on a similar concept transport refrigeration machine for cooling the interior of a box body of a refrigerated vehicle is known. Also in this machine, the drive motor and the compressor form a compressor unit. However, here the drive motor is flanged with its own tightly enclosing him housing to the also own housing of the compressor, so that the drive shafts of the drive motor and compressor coaxially aligned with each other and can be directly connected. The compressor is in this case a so-called

"open compressor". In this type of compressor, the opening from which its drive shaft exits, sealed by means of a shaft seal acting against the drive shaft relative to the respective environment. However, this seal is not hermetic, because due to the relative movement between the seal and rotating

Drive shaft in the compressor housing under pressure at the shaft seal pending refrigerant fluid through the sealing gap in which the relative movement takes place is dragged out. The refrigerant leaving the compressor enters the motor housing of the flanged valve in an uncontrolled manner

Drive engine and expanded there. As a result, rises the pressure inside the motor housing with increasing amount of introduced refrigerant. In order to prevent damage to the drive motor as a result of this increase in pressure, a valve is provided on the motor housing which opens when a limiting pressure is reached, so that the refrigerant can escape into the environment in a controlled manner.

The advantage of a machine based on an open compressor is increased

Serviceability and improved

Energy efficiency. Also, the advantage of the improved cooling that a hermetically sealed arrangement of drive motor and compressor has in a common housing can be achieved under normal operating conditions using an open compressor

Compressor unit of the type described above are compensated by the fact that the drive motor is selectively positioned in a Kühlluftström, by the

Chiller is passed. However, in practical driving at particularly high ambient temperatures, the operating temperatures of the drive motor increase so much that additional measures for cooling the engine are required under such extreme conditions.

In order to allow a cooling of the drive motor by means of refrigerant also in a likewise based on an open compressor compressor unit in which the drive motor is flanged directly to the compressor, has been proposed in DE 101 01 975 A1, refrigerant in

Circuit via a separate outer coolant path from the compressor housing in the motor housing and from there via to lead a channel formed in the common drive shaft of the compressor and the drive motor back into the compressor. The so flowing through the motor housing

Refrigerant removes the waste heat produced by the drive motor so that harmful temperature peaks are avoided. However, this requires not only a comparatively complicated design of the components, which are flowed through by the out of the motor housing back into the compressor refrigerant, but also a

pressure-resistant design of the motor housing ahead. Examples of such compressor unit concepts are from the

No. 2,864,551 and US Pat. No. 6,871,512 B2.

It should also be mentioned in this connection that cooling of the drive motor by means of water cooling has already been proposed for stationary refrigerators.

Against the background of the above-described prior art, the object of the invention to provide a compressor unit, in which simple

Means even when operating under extreme conditions

Ambient temperatures optimum operating temperatures can be safely met.

Likewise, a commercial vehicle with a chiller should be created in which even under high

Ambient temperatures a high level of operational safety

is guaranteed.

With respect to the compressor unit, this object has been achieved according to the invention in that a such compressor unit has the features specified in claim 1.

With regard to the commercial vehicle, the solution of the above-mentioned object is that in the refrigerator of such a commercial vehicle, an inventive

Compressor unit is used.

Advantageous embodiments of the invention are specified in the dependent claims and are explained in more detail below as the general inventive concept.

A compressor unit according to the invention for compressing refrigerant thus comprises, in accordance with the prior art described above, an electric drive motor having a motor housing which encapsulates the drive motor from the environment, and a compressor driven by the drive motor

Compressing a refrigerant drawn from the compressor as a refrigerant suction flow. According to the invention, the motor housing of the drive motor is now at least partially flowed around at least by a partial flow of the refrigerant suction flow, wherein the flow around is not necessarily constant, but may be required. According to the invention thus the motor housing of the drive motor of the

Flowed refrigerant flow, which flows to the compressor unit. Typically, the drive motor is arranged in the refrigerant suction stream which, after having coupled it to the compressor unit according to the invention

Heat exchanger has happened, on the way back to

Evaporator is. Unlike the known concepts, therefore, in a compressor unit according to the invention due to the fact that in her no compressed refrigerant fluid in the vom

Motor housing enclosed engine compartment is passed, even the motor housing itself do not meet any special requirements. It can thus be used as far as possible conventionally designed components, resulting in the cost of producing a novel

Minimize compressor unit.

In principle, the compressor unit according to the invention can be arranged at any point in the intake flow of the compressor, at which the motor housing of the drive motor in sufficient for heat dissipation from the to

Intake side of the compressor flowing back

Refrigerant flow is flowed around. One as compact

Unit ready pre-assembled design of

The invention is characterized in that it comprises a motor housing jacket, which at least partially the motor housing to form a with a

Ansauganschluss the compressor connected flow channel einhaust through which flows in the cooling operation of the refrigerant suction flow.

The motor housing jacket can be the motor housing

At least circumferentially completely encase with a certain distance, so that between the inner peripheral surface of the shell and the outer peripheral surface of the drive motor, a circumferential, serving as a channel for the refrigerant gap is formed. It is equally possible, of course, only at the points of the motor housing, where it comes to a particularly strong heat or where a particularly effective heat dissipation is possible, by means of a suitable sheath a

Forming flow channel for the refrigerant suction flow. It is also conceivable, in the manner of cooling coils, to place a tubular channel around the motor housing, through which the refrigerant suction flow flows and which is in good thermal contact with the motor housing. Likewise, it may be expedient to design the jacket housing the motor housing in such a way that the refrigerant suction stream flows against the end face of the motor housing facing away from the compressor and starts from there

also like a coat around the motor housing lays.

In many applications, it will be sufficient at medium or low ambient temperatures when the heat generated by the drive motor of a compressor unit according to the invention in a conventional manner by a

Airflow or the like is discharged and the

Cooling according to the invention by the refrigerant suction flow is used only at high temperatures.

Accordingly, in a practical embodiment of the invention, a control device for adjusting the refrigerant suction flow is provided, which flows around the motor housing. This control device can be set, for example, so that the cooling refrigerant flow is passed only to the motor housing when a certain high outside temperature is exceeded. The additional energy required for the compression of the waste heat of the drive of a device according to the invention

Compressor unit additionally heated refrigerant must then be applied only in this operating condition. Even with a compressor unit according to the invention, a particularly compact design can be characterized

accomplish that the drive motor with his

Motor housing is tightly connected to an associated side of a housing of the compressor and that

at the same time the interconnected drive shafts of drive motor and compressor coaxial with each other

are aligned.

If, according to the pattern of the prior art, an open compressor is used which can be inexpensively maintained and maintained with comparatively little effort, then the engine compartment delimited engine compartment and the crankcase bounded by the housing of the compressor can move against each other by means of a counter to the

Drive shaft of compressor or drive motor acting seal to be sealed. Again, it is in operation in the range between the stationary seal and the respective rotating drive shaft technically unavoidable sealing gap for removing a

Leakage flow coming from the compressor, which then penetrates into the motor housing. The leakage flow consists of refrigerant or oil, which is present in the crankcase of the compressor, wherein refrigerant and oil can of course escape as a mixture. In order to keep the entrained leakage amount as low as possible, it may be appropriate to form the seal as a shaft seal package, which is formed by at least two in the axial direction of the drive shafts of the compressor and drive motor with spaced shaft seals, which define a sealing space between them. In such a cascade of multiple shaft seals each shaft seal is a further obstacle to the passage of refrigerant or oil into the engine compartment.

However, with the currently available

Never completely prevent seals from leaking into the motor housing through the sealing gap of the seal in an open compressor. The refrigerant entering the engine compartment enclosed in the engine compartment expands due to the lower pressure there, resulting in a pressure increase in the engine housing. In order nevertheless to be able to use a light and cost-effective motor housing produced from a thin sheet metal material or the like, at least one outlet for discharging refrigerant, oil or other residues may be provided in a compressor unit according to the invention

Leakage current through the seal from the housing of the

Compressor enter the motor housing.

In the event that for sealing the compressor housing relative to the drive shaft, a shaft seal package is provided with a sealing space enclosed therein, it may be expedient to connect such an outlet to the seal chamber of the seal. In this way, the leaking from the compressor leakage volume can be deducted before it in the motor housing

enclosed engine compartment passes. Alternatively or additionally, it may also be expedient to also protect the engine compartment against an excessively high overpressure of the atmosphere prevailing in it by virtue of the fact that refrigerant present in the engine housing and gaseously expanded can be discharged via an outlet. If available, it is of course expedient to provide the outlet provided in each case with an outlet valve. This can be particularly useful when the outlet is guided into the environment, as a controlled deflation is possible. The respective exhaust valve can be designed and

be designed so that it opens automatically when inside the engine compartment or within the seal chamber as a result of evaporation or the penetration of

entrained refrigerant increasing pressure

Exceeds limit pressure.

The pollution of the environment by leaking from the compressor unit refrigerant fluid can be minimized in that the output of at least one of each provided

Outlets in the refrigerant suction flow opens. In this case, therefore, the coolant entering the engine compartment of the drive motor or the seal chamber of the shaft seal package is no longer discharged into the environment, but returned directly to the refrigerant circuit. In this way, a compressor unit is available, in which, although an open compressor combined with an opening when an overpressure equally opening motor housing and can therefore be manufactured and maintained inexpensively, but nevertheless ensures that, despite an unavoidable

Leakage flow at best minimal amounts of refrigerant into the free environment.

In order to avoid any risk of excessive pressure in the motor housing, it may be useful when reaching a certain limit pressure in the engine compartment There existing, expanded to gas refrigerant to discharge into the environment, whereas in the area of the seal trapped leakage volume, consisting of refrigerant, oil or other residues, directly back into the

Refrigerant intake flow is returned. The

Pressure relief of the motor housing is also in this embodiment in the sense of an emergency function only in the rarely occurring case when the entrained by the seal in the motor housing refrigerant is greater than the previously collected from the seal chamber

Amount of refrigerant.

The effectiveness of the removal of refrigerant from the

optional in the area of sealing existing

Sealing space can be increased by the fact that

Flow channel has a bypass section and that a control device is provided for regulating the refrigerant flow through the bypass section. Such a bypass section of the flow channel for the

Refrigerant suction flow can be optimized in terms of flow so that the refrigerant flowing through the bypass to the suction side of the compressor flows out of the

Exhaust valve entrains escaping refrigerant and dissipates from the shaft seal.

Basically, the advantages of a

inventive design of a compressor unit in all chillers that must be operated at high temperatures and in which it is possible to the

Compressor recirculated refrigerant flow to the

To guide the motor housing. This possibility proves to be particularly advantageous in commercial vehicles with a Cargo space and a chiller for tempering the atmosphere contained in the hold. Since such commercial vehicles are used at very different temperatures, it proves to be particularly advantageous if just the cooling machines provided for them in a

trained according to the invention and thus high

effectively coolable compressor unit includes.

However, this possibility also turns out to be the case

Area of bus air conditioning, railway air conditioning and transport refrigeration as generally advantageous. Accordingly, devices for air conditioning buses and trains, for example railways, light rail vehicles etc. with a compressor unit designed according to the invention, as well as buses and trains with a compressor unit designed according to the invention are also included in the idea of the present invention. Furthermore, transport refrigeration devices in the general sense, for example, for sea containers,

Railroad cars and refrigerated containers for road and / or rail transport provided with an inventively designed compressor unit.

As already mentioned, depending on the design, only a partial flow of the refrigerant suction stream sucked in as the suction gas by the compressor of a compressor unit according to the invention or the entire suction gas can be provided for cooling the engine. Thus, depending on the application, a desired amount of heat can be dissipated by the suction gas from the engine. This of course excludes the possibilities, the whole

Amount of heat generated in the area of the engine to dissipate via the refrigerant suction flow. Optionally, a remainder of the heat generated in the region of the drive motor can be boosted by the natural heat radiation of the motor housing, in turn optionally forced by a blown against the motor housing or its casing

Airflow, be dissipated. Thus, in particular air-cooled cooling devices can be dimensioned to a desired size, in particular reduced in size. Alternatively, it is possible to completely dispense with an appropriate dimensioning of the system parts to an air cooling.

For the already mentioned possibility, the

For example, regulated flow cross sections for the suction gas used for cooling can be implemented for controlling the respective refrigerant suction flow for cooling around the motor housing or along the same.

Suitable devices for this purpose are, for example, valves or diaphragms. Control parameters can be, for example, the temperature of the motor or the motor housing.

As a compressor, in an inventive

Compressor unit each controllable compressor, in particular an axial piston compressor with stepless stroke control, such as a swash plate compressor or swash plate compressor are used. It should be noted at this point that the in the compressor housing bounded volume, ie in the crankcase, existing compressor pressure is expediently greater than or equal to the suction pressure and less than or equal to the high pressure. Hereinafter, the invention with reference to a

Embodiment illustrative drawing closer

explained. Each show schematically:

Fig. 1 shows a first embodiment of a compressor unit in a longitudinal section;

Fig. 2 shows a second embodiment of a compressor unit in a longitudinal section.

The compressor units V1, V2 shown in the figures each include an electrically driven drive motor 1 and a compressor 2. The compressor 2 is designed in the swash plate design. However, it goes without saying that, alternatively, any other type of compressor can be used, so for example one

Scroll compressor, a rotary compressor, a

Radial piston compressor or an axial piston compressor with constant piston stroke.

The compressor 2 is used for compressing a refrigerant, which is, for example, a commercially available synthetic or natural refrigerant.

For compression, the compressor 2 comprises pistons 3,4. The pistons 3, 4 are linearly reciprocable in cylinder chambers 5, 6, which are formed in a cylinder block 7. The pistons 3, 4 are each articulated via a connecting rod 8, 9 and in each case one sliding block 10, 11 to a swivel disk 12. In addition, a drive shaft 13 of the compressor 2 with its end remote from the drive motor 1 is mounted in the cylinder block 7. The swash plate 12 is rotatably in operative engagement with the drive shaft 13. It is relative to

Drive shaft 13 to a normal to the drive shaft 13 aligned and the drive shaft 13 piercing

Pivoting pivot axis and so in their inclination relative to the drive shaft 13 adjustable. The resulting pivoting directions are in the figures by a

Double arrow 14 illustrates.

By changing the enclosed between the drive shaft 13 and the swash plate 12 inclination angle ß the stroke of the piston 3,4 and thus the geometric displacement can be adjusted continuously. The further the inclination angle β deviates from 90 °, d. H. the smaller the angle of inclination β becomes, the larger the delivery volume becomes, since the stroke of the pistons 3,4 becomes correspondingly larger. In alternative, not shown embodiments, the swash plate 12 may also have the shape of a pivot ring.

The compressor 2 has a compressor housing 15, which defines a crank chamber 16. In the crank chamber 16, the swash plate 12 is mounted on the guided drive shaft 13. It is in the crankcase 16 a

Crankcase pressure PK, the here described

Embodiment is adjustable. By adjusting the crank chamber pressure PK can be adjusted in a conventional manner, the inclination of the swash plate 12 and thus

accompanying the stroke and delivery volume of the compressor 2 are changed. This is done by the fact that the

Crank chamber pressure PK on the crank chamber 16 associated side of the piston 3,4 works, so that at elevated Crank chamber pressure PK of the suction movement of the piston 3.4 counteracts an increased force and consequently in the

Suction movement covered piston travel is smaller than at a low piston chamber pressure PK.

To secure the lubrication of moving in the crankcase 16 parts is in the crank chamber 16 a certain

Quantity of oil available, of which at least one

Subset at the bottom of the crank chamber 16 as the oil sump S

collects.

Further, the compressor 2 comprises a cylinder head 17, in which a suction chamber 18, which is acted upon by a suction pressure, and a pressure chamber 19 are arranged, which is acted upon by a high pressure. Via the suction chamber 18 to be compressed refrigerant via an inlet valve 20 into the cylinder chambers 5,6 of the compressor and is there compressed by the reciprocating piston 3,4.

The compressed refrigerant passes through outlet valves 21 into the pressure chamber 19, from where it is fed via an outlet, not shown here, to a heat exchanger, also not shown here, through which the atmosphere to be cooled flows.

The inclination angle ß can be adjusted in a conventional manner by adjusting the compressor pressure in the crank chamber 16. This can also be a se

known, be provided here, not shown control device. For the increase of the compressor pressure is the

Crank 16 via a compressed gas connection 22 with the Pressure chamber 19 and connected to the lowering of the pressure via a discharge connection 23 to the suction chamber 18.

In the examples described here, the

Compressed gas connection 22 be unregulated while in the

Relief connection 23 a control valve 24 is arranged. Alternatively, however, a control valve 25 in the

Compressed gas connection 22 may be provided or it may be set in addition to the control valve 24 in the compressed gas connection 22, such a control valve to both the

Pressure relief and the pressurization can be regulated separately. As an alternative to a valve, adjustable diaphragms or the like would also be conceivable, for example. The prevailing in the crank chamber 16

Crank chamber pressure is greater than or equal to the suction pressure and less than or equal to the high pressure to which the refrigerant is exposed in the pressure chamber 19 after compression.

With its end remote from the cylinder head 17, the drive shaft 13 of the compressor through an opening in the drive motor 1 associated end face 26 of

Compressor housing 15 is guided there and engages positively and non-rotatably in a receptacle of the drive shaft 27 of the drive motor 1. In this way, a rotationally fixed, but releasable connection between the drive shafts 13,27 is formed.

The sealing of the compressor housing 15 with respect to the drive motor 1 is effected on the compressor side by a stuffing box 28 arranged in the region of the end wall opening and acting against the drive shaft 13. In addition, another seal by a

Shaft seal 29 formed. To this end, the shaft seal 29 sits in an end opening formed as a receiving opening of a motor housing 30 accommodating the drive motor 1 and also acts against the associated peripheral surface of the motor housing 30 protruding

Drive shaft 13. The gland 28 and the shaft seal 29 thus form a shaft seal package. In doing so, they define between them a sealing space 31 which is delimited on the circumference by the inner peripheral surfaces of the passage opening or a holder for the shaft seal 29 inserted therein.

The drive motor 1 is described here

Embodiments connected to a speed control device 32. Of course, a stationary, unregulated operation is possible if this is sufficient for the particular application.

The conventionally constructed drive motor 1 is located with the end face of its motor housing 30 close to the associated end face 26 of the compressor housing 15 and is detachable with the compressor housing 15 in a conventional manner by means not shown here screws

connected.

The drive motor 1 is encased by a motor housing shell 33, which is laid in each case at a uniform distance around the outer peripheral surface of the motor housing 30 and also remote from the compressor 2 at a distance

Front side 34 of the motor housing 30 covers. In this way, the motor housing 30 is circumferentially and on at its End 34 wrapped by a gap 35. Of the

Motor housing jacket 33 abuts against the end face 26 of the compressor housing 15 and is connected to this tight, but also releasably connected.

Via a suction outlet 36 arranged close to the compressor 2, the gap 35 delimited by the motor housing jacket 33 is connected to a suction line 37 which leads to the suction chamber 18 of the compressor 2.

In addition, in the end face of the motor housing shell 33, a suction inlet 38 is formed, to which an outflow line 39 of the not shown here, of the respective

Compressor unit V1, V2 supplied heat exchanger

connected.

Through the discharge line 39, a refrigerant suction flow K of expanded refrigerant flows back to

Compressor 2. The refrigerant suction flow K entering the motor casing jacket 33 floods the gap 35, thereby sweeping waste heat of the drive motor 1 over the outer surfaces of the motor casing 30. Next, the refrigerant suction flow K is sent to the suction side of the compressor 2 via the discharge line 39 passed, there compacted in the manner described above and then fed back to the heat exchanger.

In this way, the heat generated during operation of the drive motor 1 is reliably removed from the motor housing shell 33 by means of the refrigerant suction flow K and ensures effective cooling of the drive motor 1 even at high ambient temperatures. If the respective compressor unit V1, V2 is operated at temperatures which are below a maximum limit, flow through the gap 35 can be dispensed with. In this case, in the compressor unit VI one of

Suction inlet 38 directly to the suction line 37 leading and thus the gap 35 bypassing line 40 provided which is opened or closed depending on the temperature.

Arrangements have been made in the compressor unit V2 to prevent the generation of overpressure in the motor housing 30 by a leakage current L unavoidably introduced into the motor housing 30 via the sealing gaps of the gland 28 and the shaft seal 29. This

Leakage flow L consists of refrigerant and oil, and in

Engine housing 30 to prevent expanding refrigerant. For this purpose, on the one hand from the seal chamber 31, a drain line 41 a is guided, which opens at the ümfangsseite of the motor housing 30 in the gap 35 near the suction outlet 36 of the motor housing shell 33. About the drain line 41a passes into the sealing chamber 31 reaching refrigerant and is taken from the flowing through the gap 35 refrigerant suction flow K before it enters the engine compartment 30 enclosed by the engine compartment.

Another outlet 41b also leads near the

Suction outlet 36 from the motor housing 30 in the gap 35. About this outlet 41 b, oil and other liquid residues, via the leakage flow L in the of

Pass motor housing 30 bounded engine compartment and collect as a result of the influence of gravity on the mounting position shown in the figures lower side, drain. Also, the so reaching into the gap 35 liquid Residues are taken from the refrigerant suction flow K and separated, for example, in a separator not shown here from the refrigerant. If necessary, the outlets 41a, 41b can each be equipped with a valve which automatically opens at the outlet 41a, 41b at a certain pressure, which is not shown here

for example, with stationary compressor unit V2

Penetration of refrigerant from the refrigerant suction flow K in the outlets 41 a, 41 b to prevent.

In spite of the outlet 41a, refrigerant passing into and expanding in the motor housing 30 can be discharged into the free environment U in a manner known per se via a relief valve 42 connected to the engine compartment 30 enclosed by the engine housing 30

automatically opens when the pressure in the motor housing 30 reaches a limit.

A bypass line 43 is also provided in the compressor unit V2 shown in FIG. 2, but in this case it is integrated in the motor housing shell 33. Through a valve combination 44, the flow through the gap 35 or the bypass line 43 of the respective

Ambient temperature load to be regulated accordingly.

REFERENCE NUMBERS

1 electric drive motor 1

2 compressors

3.4 piston of the compressor 2

5.6 cylinder chambers of the compressor 2

7 cylinder block

8.9 connecting rods

10,11 sliding blocks

12 swivel disc

13 drive shaft

14, the pivoting directions of the swash plate 12th

15 compressor housing

16 crankcase

17 cylinder head

18 suction room

19 pressure room

20 inlet valve

21 exhaust valves

22 compressed gas connection

23 Relief connection

24 control valve

25 control valve

26 front side

27 drive shaft

28 stuffing box

29 shaft seal

30 motor housing

31 sealing space

32 speed control device

33 Motor housing jacket

34 front side

35, a flow channel forming gap

36 suction outlet

37 suction line

38 suction inlet

39 outflow line

40 bypass line

41a, 41b drain line

42 relief valve (exhaust valve)

43 line

44 Valve combination ß inclination angle swivel disc 12

K refrigerant suction flow

L leakage current

PK crankcase pressure S oil sump

U environment

V1, V2 compressor units

Claims

PATENT APPLICATIONS

Compressor unit for compressing refrigerant, with an electric drive motor, a the

Drive motor (1) opposite the environment (U)

encapsulating motor housing (30), and having a driven by the drive motor (1) compressor (2) for compressing a refrigerant from the compressor (2) as the refrigerant suction flow (K) sucked refrigerant

At least a portion of the motor housing (30) of the drive motor (1) is at least temporarily surrounded by at least a partial flow of the refrigerant suction flow (K).

2. Compressor unit according to claim 1, d a d u r c h

You can not use one

Motor housing jacket (33), the motor housing (30) at least partially to form a with a suction port of the compressor (2)

connected flow passage (35) einhaust, through which flows in the cooling operation of the refrigerant suction flow (K).

3. Compressor unit according to claim 2, characterized in that d

Flow channel (35) along the peripheral surfaces of the motor housing (30) extends.

4. Compressor unit according to claim 2 or 3, d a d u r c h e c e n e s e s t e, s e s the

Flow channel (35) along the side facing away from the compressor (2) front side (34) of the motor housing (30).

5. compressor unit according to one of the preceding

Claims, d a d u r c h e k e n e, in which a control device for adjusting the refrigerant suction flow (K) is provided, which flows around the motor housing (30).

6. compressor unit according to one of the preceding

Claims, characterized in that the drive motor (1) with its motor housing (30) is connected tightly to an associated side (26) of a housing (15) of the compressor (2) and that the interconnected drive shafts (13,27) of the drive motor (1) and compressor (2) are aligned coaxially with each other.

7. compressor unit according to claim 6, d a d u r c h

e e n c ia n e, the s of the

Motor housing (30) bounded engine compartment and the of Housing (15) of the compressor (2) bounded crank chamber (16) against each other by means of a against the drive shaft (13) of the compressor (2) or drive motor (1) acting seal (28,29) are sealed.

8. compressor unit according to claim 7, d a d u r c h

The seal is designed as a shaft seal packet, which is formed by at least two in the axial direction of the drive shafts

(13,27) of compressor (2) and drive motor (1) with spaced-apart shaft seals (28,29) is formed, which define a sealing space between them (31).

9. Compressor unit according to claim 7 or 8, d a d u c c h e c e n e s, it s at least one outlet (41 a, 41 b, 42) for discharging a via the seal in the motor housing (30) entering

Leakage current (L) has.

10. Compressor unit according to claim 8 and 9, d a d u r c h e c e n e c e s e, an outlet (41 a) for discharging the leakage flow (L) is connected to the seal.

11. Compressor unit according to one of claims 9 or 10, d a d u r c h e k e n e z e c h e n e, s at the respective outlet an outlet valve (42) to the

Engine room is connected.

12. Compressor unit according to claim 10, wherein the respective outlet valve automatically opens when the pressure rising inside the engine compartment or within the seal chamber as a result of the expansion of entrained refrigerant exceeds a limiting pressure.

13. Compressor unit according to claim 10, wherein at least one of the respectively provided outlets (41a, 41b) discharges into the refrigerant intake flow (K).

14. Compressor unit according to claim 2 and 13, d a d u c h e c e n e c e s, d a s s of

Flow channel (35) has a bypass section (40,43) and d sa s s a control device (44) for controlling the refrigerant flow through the bypass section (40,43) is provided.

15. Commercial vehicle with a cargo space and a

Chiller for tempering in the hold

atmosphere, wherein the cooling machine comprises a compressor unit (V1, V2) designed according to one of the preceding claims.