EP1662141B1 - Axial piston compressor - Google Patents

Description

The invention relates to an axial piston compressor, in particular a compressor for the air conditioning system of a motor vehicle, according to the preamble of patent claim 1.

Such compressors are for example from the DE 196 47 861 , of the EP 0 688 953 , of the EP 0 838 590 , of the EP 0 911 517 , of the US 5,704,769 , as well as the US 5,733,107 known. The above-cited references relate to compressors with a non-variable displacement, ie the tilt angle of the piston driving the swash plate is not changeable. Furthermore, such and in particular the compressor described in the cited documents often double or double-acting piston. In such constructions, usually the engine as well as a surrounding engine compartment with respect to the axial extent are arranged centrally. To this end, two cylinder blocks are usually connected on both sides, in each of which one end of the two piston ends of the piston is guided. Usually are in these constructions usually three double-acting pistons.

Considering such a double-acting piston, when the one piston end is in its associated cylinder block or the associated cylinder bore in the top dead center, the other end of the piston in its associated cylinder block or its associated cylinder bore in the bottom dead center position. As is common in all compressors of this type, the cylinder blocks, more specifically the cylinder bores, are terminated by a valve plate assembly, which typically consists of a valve plate, suction valves, pressure valves and valve stoppers.

The assembly of the valve plate in turn is followed by a cylinder head, which separates a suction chamber from a pressure gas chamber. Due to the explained compressor design cylinder block, valve plate assembly and the cylinder head are present in pairs.

In the mentioned compressors, there are only two pressure levels, namely the pressure in the intake state of the compressor (suction pressure), as well as the pressure after the compression process (compression pressure). There is no further pressure between these two pressure levels. A pressure in the engine caused by leakage gas (piston), which is greater than the suction pressure (and less than the compression pressure) is prevented by a short circuit or connection to the suction side.

By contrast, with a compressor which can be regulated above the tilt angle of the swash plate, the swash plate tilt angle is changed by varying the pressure in the engine compartment. The pressure in the engine room can be varied to pressures between the high pressure level (i.e., the compression pressure) and the low pressure level (suction pressure).

The compressors according to the prior art are usually driven by a guided out of the compressor housing shaft end. For this purpose, for example, magnetic clutches and pulleys are used, via which the compressor with the engine speed can be driven.

Since in a construction based on the concept of a double-acting piston assembly two cylinder heads must be used, the shaft must be guided out of the compressor housing through a central bore of a cylinder head. For driving, as already mentioned above, usually a magnetic coupling is used. As a shaft seal, L13 primarily uses lip seals in one to several stages. Axial slip ring seals are still under discussion, in particular with the desire to further reduce leaks for the refrigerant R134a or for the application of CO ₂ as a refrigerant. It should be noted at this point that lip seals are also under discussion in connection with CO ₂ as the refrigerant.

Typically, in compressors with a double-acting piston assembly, the shaft seal, regardless of which type it is, corresponds to the lower pressure level. This is the engine including drive shaft and shaft seal subjected to the suction pressure. The impingement of the engine (despite any existing leaks) with the suction pressure is, as stated above, achieved by a short circuit between the engine chamber and suction chamber.

In the compressors described in more detail above, the cylinder head including the shaft seal includes, in concentric arrangement, a shaft seal chamber, as well as an annular suction chamber and an annular pressure chamber.

In contrast, for example, by the series compressor "DKS-15" of the Zexel Corporation, a construction is known in which the shaft seal is integrated directly into the centrally arranged suction chamber. In other words, this means that the shaft seal chamber, which is located in the center, coincides with an annular suction chamber. As a result, the pressurized gas chamber is concentric and annularly disposed around the suction chamber.

Such an arrangement is for example also from the EP 0 838 590 known while according to the DE 196 47 861 , of the EP 0 911 517 , of the US 5,704,769 and the US 5,733,107 , as well as the EP 0 688 953 a division of the cylinder head takes place in three chambers.

Similar compressor designs with respect to a division of the cylinder head into two chambers, for example, from EP 1 164 289 , of the EP 1 233 180 , of the EP 1 239 154 and the DE 102 06 748 known. The compressors described in these publications are essentially controllable with respect to their piston stroke compressor, in which the pistons are effective on one side.

As already mentioned, the shaft seals are usually arranged in the centrally located suction chamber. In compressors whose piston stroke is adjustable, the shaft seal is usually arranged in the axial extension on the cylinder head opposite side.

An arrangement of the shaft seal, in particular a mechanical Axialgleitringdichtung in the cylinder head or in the suction chamber has the advantage that the shaft seal on the one hand comparatively well by the suction gas in the suction chamber can be cooled and on the other hand by the lowest pressure within the compressor is applied (as for compressors with uncontrolled stroke is the case).

A disadvantage of the objects of EP 1 164 289 , of the EP 1 233 180 , of the EP 1 239 154 as well as the DE 102 06 748 is that the oil supply to the shaft seal is not optimally solved in operation, the refrigerant can be comparatively little cooling effect that the shaft seal, in particular the sealing gap, are in a kind of dead space (poor oil circulation) and that at compressor standstill no oil reservoir on the sealing rings can be present (oil flows away from the sealing gap), which inevitably leads to leaks in long downtimes.

Finally, it should be added to the state of the art US 4,229,145 A which describes a double-acting axial piston compressor, wherein the sealing of the drive shaft is realized by a shaft seal positioned in a suction or inlet chamber. In such compressors, it is - as already mentioned - disadvantageous that the oil supply to the shaft seal is not optimally solved in operation and also the refrigerant can be comparatively little cooling effect. Furthermore, the shaft seal, in particular the sealing gap, in a kind of dead space, resulting in a poor oil circulation, it should also be noted that at a compressor standstill no oil reservoir can be applied to the sealing rings, as the oil flows away from the sealing gap, which inevitably leads to leaks during long downtimes.

Based on this prior art, it is an object of the present invention to provide a compressor in which the oil supply both at longer downtime and during operation of the compressor and the suction gas cooling of the shaft seal are improved.

This object is achieved by a compressor with the features of claim 1, wherein preferred developments and embodiments are described in the subclaims.

A compressor according to the invention comprises a housing, a cylinder block, at least one in the cylinder block axially reciprocating piston and a cylinder head. A suction chamber is disposed substantially in the cylinder head and the compressor further includes a suction gas inlet and a drive shaft. An essential point of a compressor according to the invention is that the drive shaft between the suction chamber and the Sauggaseintritt is sealed to the outside, through a shaft seal. This ensures that the oil supply to the shaft seal is also optimized for longer downtime and in the operation of the compressor, since the oil can not flow out of the chamber (internal sealing element or oil level protection), while the suction gas cooling of the shaft seal also reaches an optimum level.

In a preferred embodiment, the shaft seal is arranged within a separate shaft sealing chamber, whereby an assembly-and maintenance-friendly (eg when mounting the shaft seal from the outside) axial piston is formed. The shaft sealing chamber is preferably arranged between the suction chamber and the Sauggaseintritt, which ensures a constructively low cost. In a further preferred embodiment, an annular space is defined between the peripheral wall of the shaft sealing chamber and at least part of the shaft seal arranged therein, into which opening the suction gas inlet opens. The annulus communicates preferably with an axial gap between the end face of the shaft seal and the end wall facing the side wall of the shaft seal chamber. The width of the annular space and / or the axial gap is approximately between 1.5 mm and 5.0 mm. The above-mentioned embodiments represent structurally simple variants of a compressor according to the invention, wherein the fact that the mean diameter of the shaft seal chamber is not significantly greater than the mean diameter of the shaft seal itself, the advantage that the entrained in the refrigerant flow oil or the In the refrigerant flow entrained oil tends to be larger than a relatively large shaft seal chamber. Furthermore, the flow rate of the refrigerant is comparatively larger and the cooling effect by turbulence and the corresponding forced convection greater than in a compressor with a larger shaft seal chamber.

In a further preferred embodiment, the cylinder head is formed in one piece, which ensures a low production cost. An alternative embodiment is characterized in that the cylinder head is made in two parts. The components of the cylinder head may consist of the same materials, for example aluminum, or of different materials, for example of aluminum and steel. Components containing large cavities can be constructed of a solid material (this is particularly advantageous for the use of CO ₂ as a refrigerant), while the component that incorporates the shaft seal is made of a material that has good thermal conductivity. is trained. A possible material for this is aluminum, which is distinguished not only by its good thermal conductivity but also by its low weight. This ensures sufficient heat dissipation to the environment.

A rotatably connected to the drive shaft pulley preferably has flow elements which cause a rotation of the same an air flow, which are directed to the cylinder head and the shaft seal receiving component of the compressor, so for example the shaft seal chamber. The pulley is arranged on the side of the compressor facing the suction chamber. In addition to its functionality with respect to the drive of the compressor according to the invention, the pulley thus assumes a second function, namely to cool the compressor accordingly. As a result, optimal heat dissipation is achieved with low structural means. In a further preferred embodiment, the shaft sealing chamber is designed such that when a standstill of the compressor, an oil reservoir is held in the same. This ensures optimum oil supply, with an oil barrier wall and / or a labyrinth seal and / or a sealing lip is or are preferably arranged in the shaft sealing chamber for holding the oil reservoir. The seal in the region of the shaft enables optimum oil supply, the preferred embodiments are easy and inexpensive to produce with respect to the type of seal.

The oil reservoir preferably reaches at least the lower edge of a sealing gap of the shaft seal. This implies that the suction gas inlet leading into the shaft sealing chamber and the suction gas outlet leading out therefrom (toward the suction chamber) are arranged with respect to the installation position of the compressor so that they are by no means located on the underside of the shaft seal chamber or arranged so that complete emptying of the chamber is made possible, for example in compressor standstill. In an advantageous embodiment, all openings and recesses of the shaft sealing chamber, in particular the openings for the connections between the shaft sealing chamber and the Sauggaseintritt or the shaft seal chamber and the suction chamber above the lower edge of the sealing gap of the shaft seal. As a result, leakage of the oil that is to form the oil reservoir, in particular in a compressor standstill, effectively prevented. The opening in the shaft sealing chamber for the connection between the shaft sealing chamber and Sauggaseintritt is arranged such that it lies between the lower edge and the upper edge of the sealing gap. This ensures efficient cooling. Preferably, the opening for the connection between the shaft sealing chamber and suction gas inlet is located centrally between the lower edge and the upper edge of the sealing gap.

In another embodiment, the openings for the connections between the shaft seal chamber and the suction gas inlet or the shaft seal chamber and the suction chamber are also arranged at a different level in the shaft seal chamber. Also, the arrangement at different heights, the cooling function is improved. A further preferred embodiment of a compressor according to the invention promotes an optimal cooling function for the compressor: In said embodiment, the suction duct is formed such that from this emerging suction gas or the entire of this emerging suction gas flows mainly to the region of the sealing gap of the shaft seal and / or order the shaft seal is turned around. Such a construction further avoids a kind of "dead space" in terms of cooling.

As already stated above, the shaft seal in a compressor according to the invention should not only be cooled substantially by the suction gas and the entrained oil, but also by a heat dissipation to the outside, i. So a heat dissipation to the environment, which can be done directly or indirectly via the housing parts. For this purpose, in a preferred embodiment, the cylinder head is formed at least in two parts, wherein between at least two components of said cylinder head, a thermal insulation is arranged so that in the shaft seal a comparatively cool component, in particular of a thermally highly conductive material such as aluminum is made. The thermal insulation preferably comprises a steel sheet which is disposed on one or both sides, i. that is, elastomer-coated on a cylinder block facing side of the steel sheet and / or on a side facing away from the cylinder block of the steel sheet.

In a particular embodiment, the shaft seal comprises a lip seal or an axial mechanical seal. This ensures a structurally easily executable embodiment of a compressor according to the invention. Furthermore, in a further preferred embodiment, cooling fins are arranged on the cylinder head, which ensure good heat dissipation.

To increase safety, a check valve is preferably arranged in or at the connection between the suction gas inlet and the shaft sealing chamber.

Fig. 1

eine bevorzugte Ausführungsform eines erfindungsgemäßen Verdichters im Querschnitt;

Fig. 2

eine vereinfachte Darstellung der Fig. 1 mit einer vergrößerten Detailansicht einer Wellenabdichtungskammer im Querschnitt entlang einer Schnittebene I-I sowie als schematische Darstellung;

Fig. 3

wiederum eine vereinfachte Darstellung der Fig. 1 mit einer Detaildarstellung eines internen Dichtelements (a) sowie einer Detailansicht einer Lagerung (b) der Antriebswelle (jeweils in Schnittansicht); und

Fig. 4

nochmals eine vereinfachte Schnittansicht eines Verdichters gemäß der Fig. 1 mit einer Detailansicht der Wellenabdichtungskammer (im Querschnitt, entlang einer Schnittebene I-I (a)), sowie eine schematische Ansicht der Wellenabdichtung (b) .

The invention will now be described by way of example and with reference to the accompanying drawings in view of further advantages and features. The drawings show in:

Fig. 1

a preferred embodiment of a compressor according to the invention in cross section;

Fig. 2

a simplified representation of the Fig. 1 with an enlarged detail view of a shaft seal chamber in cross section along a sectional plane II and as a schematic representation;

Fig. 3

again a simplified representation of Fig. 1 with a detailed representation of an internal sealing element (a) and a detailed view of a bearing (b) of the drive shaft (in each case in sectional view); and

Fig. 4

again a simplified sectional view of a compressor according to the Fig. 1 with a detail view of the shaft sealing chamber (in cross section, along a sectional plane II (a)), and a schematic view of the shaft seal (b).

Such as the Fig. 1 can be seen, the preferred embodiment of the compressor 1 according to the invention a housing 2, a cylinder block 3 and a cylinder head 4. In the cylinder block 3, seven pistons (not shown) are mounted axially reciprocable. A suction chamber 5 is arranged substantially in the cylinder head 4 and is in communication with a suction gas inlet 6. The compressor is driven via a pulley 12 by means of a drive shaft 7. The present compressor is a variable piston type compressor, the piston stroke being controlled by a pressure difference existing between the suction gas side and an engine chamber 7a. Depending on the size of the pressure difference, a swiveling or swash plate 7b is deflected or pivoted more or less out of its vertical position. The larger the resulting swing angle, the larger the piston stroke, and accordingly, the higher the pressure at the outlet side of the compressor (DP) is provided.

A sealing of the drive shaft to the outside by a shaft seal 8, said shaft seal 8 between the suction chamber 5 and the Sauggaseintritt 6 is disposed within a separate shaft seal chamber 9. The shaft sealing chamber 9 is arranged in its entire dimensions between the suction chamber 5 and the suction gas inlet 6. Between a peripheral wall of the shaft sealing chamber 9 and the shaft seal 8 arranged therein, an annular space 10 is delimited, into which the suction gas inlet 6 opens. The annular space 10 is provided with an axial gap 11 which is arranged between an end face of the shaft seal 8 and the side wall of the shaft seal chamber 9 facing this end face. The width of the annular space 10 and the axial gap 11 is approximately 3.0 mm, it being noted at this point that a width of about 1.5 mm and 5.0 mm can affect the flow conditions in the compressor low.

The cylinder head 4 of the present preferred embodiment is formed in two parts and is composed of two components 4a and 4b and an insulation 16 together. This ensures that parts which are subjected to a high load or are subjected to high pressure, made of a correspondingly tough material (steel) are made (part 4b), while parts which are subject to lower loads (part 4a), but for are optimized for heat dissipation, are made of a lighter, thermally highly conductive material (aluminum). The two parts are separated by the thermal insulation 16. This consists of a steel sheet which has a thickness of approximately 0.3 mm and is elastomer coated on both sides. Of course, steel sheets are conceivable, which are elastomer-coated on one side only. If both sides are mentioned, then the two sides are meant, which face the cylinder block 3 and the cylinder block 3 are facing away. As mentioned, the component 4a accommodating the shaft seal 8 is made of aluminum because of the required good heat dissipation, while the member 4b accommodating the suction chamber 5 and especially the compressed gas outlet (DP) is made of steel.

The drive shaft 7 is rotatably connected to the pulley 12, wherein the pulley 12 is disposed on the side of the compressor 1 facing the suction chamber 5. The pulley has flow elements 31 which, when rotated, impinge on the cylinder head 4, i. Thus, in particular on the component 4a of the cylinder head, which comprises the shaft seal, directed air flow (indicated by the arrows 32a and 32b) effect.

The shaft sealing chamber 9 is formed such that when a standstill of the compressor 1, an oil reservoir 14 is held in the shaft seal chamber 9 (see Fig. 2 ). From the schematic representation in Fig. 2 It can also be seen that in a connection 33 between the suction gas inlet 6 and the shaft sealing chamber 9, a check valve 15 is arranged. The connection between the shaft sealing chamber 9 and the suction chamber 5 is identified by the reference numeral 34.

How out Fig. 3 , in particular from the detail drawing (a) in the FIG. 3 it can be seen, a sealing lip 17 is arranged on the drive shaft 7, which seals the engine chamber against the pressurized components of the compressor. Next to the sealing lip 17 is a bearing 35 (see also Fig. 3 (b) ) Are arranged.

The oil reservoir in the shaft seal chamber 9 exceeds, as shown Fig. 2 combined with Fig. 4 (especially Fig. 4 (a) ) is visible, a lower edge 36 of a sealing gap of the shaft seal 8. In detail, the formation of said gap in Fig. 4 shown. In a simplified illustration, the seal geometry consists of a ring 38 connected to the cylinder head 4 and a ring 39 which rotates with the shaft and is biased by a spring. From the detailed drawing of the chamber 9 in Fig. 4 are the lower edge 36 of the sealing gap as well as the Upper edge 37 of the sealing gap visible. Further, the connections 33 and 34 are shown, wherein the connection 33 as already mentioned above is the one between the shaft seal chamber 9 and suction gas inlet 6, and the connection 34 is that between the shaft seal chamber 9 and the suction chamber 5. For securely holding the oil reservoir, the openings in the shaft sealing chamber 9 for the connections 33 and 34 are arranged above the lower edge 36 of the sealing gap of the shaft seal 8. The opening for the connection 33 is arranged such that it lies centrally between the lower edge 36 and upper edge 37 of the sealing gap. In order to have ideal flow conditions and an ideal cooling effect, the openings for the connections 33 and 34, which are arranged in the shaft seal chamber 9, are arranged at a different level in the shaft seal chamber 9 (cf. Fig. 4 (a) ). The suction gas channel 13 is further designed such that the suction gas, which emerges from the suction gas channel, on the one hand flows against the region of the sealing gap of the shaft seal 8 and on the other hand is deflected around the shaft seal 8. This ensures ideal flow conditions. Finally, it should be noted that 4 cooling fins 30 are arranged on the cylinder head.

Although the invention will be described with reference to an embodiment with a fixed feature combination, but it also includes the conceivable further advantageous combinations of these features, as they are given in particular, but not exhaustive, by the dependent claims. All disclosed in the application documents features are claimed as essential to the invention, as far as they are new individually or in combination over the prior art.

LIST OF REFERENCE NUMBERS

1

compressor

2

casing

3

cylinder block

4

cylinder head

4a

Component of the cylinder head 4, which includes the shaft seal

4b

Component of the cylinder head 4, which includes the suction chamber and the outlet for compressed gas (DP)

5

Sauggaskammer

6

suction gas

7

drive shaft

7a

Engine compartment

7b

swash plate

8th

shaft seal

9

Shaft seal chamber

10

annulus

11

axial gap

12

pulley

13

suction gas

14

oil receiver

15

check valve

16

insulation

17

sealing lip

30

cooling fin

31

flow elements

32a

arrow

32b

arrow

33

Connection shaft sealing chamber 9 - Sauggaseintritt 6

34

Connection shaft sealing chamber 9 - suction chamber 5

35

camp

36

Lower edge of sealing gap

37

Top edge of sealing gap

38

ring

39

ring

Claims (22)

1. Axial piston compressor (1) having a housing (2), a cylinder block (3), at least one piston movable back and forth axially in the cylinder block (3), a cylinder head (4), an intake gas chamber (5) arranged substantially in the cylinder head (4), which intake gas chamber is connected to an intake gas inlet (6) into the compressor, and having a drive shaft (7),
   characterized in that
   the drive shaft (7) is sealed towards the outside between the intake gas chamber (5) and the intake gas inlet (6) by a shaft seal (8), the shaft seal (8) being arranged inside a separate shaft seal chamber (9), and between the peripheral wall of the shaft seal chamber (9) and at least a portion of the shaft seal (8) arranged therein there is defined an annular space (10) into which the intake gas inlet (6) opens.
2. Compressor (1) according to claim 1,
   characterized in that
   the shaft seal chamber (9) is arranged between the intake gas chamber (5) and the intake gas inlet (6).
3. Compressor (1) according to claim 1 or 2,
   characterized in that
   the shaft seal chamber (9) and the intake gas chamber (5) are arranged one after the other, i.e. side by side, in the axial extent of the compressor longitudinal axis.
4. Compressor (1) according to any one of the preceding claims,
   characterized in that
   the or an annular space (10) communicates with an axial gap (11) between an end face of the shaft seal (8) and the side wall of the shaft seal chamber (9) facing that end face.
5. Compressor (1) according to claim 3 or 4,
   characterized in that
   the width of the annular space (10) and/or the axial gap (11) is about from 1.5 mm to 5.0 mm.
6. Compressor (1) according to any one of the preceding claims,
   characterized in that
   the cylinder head (4) is of one-piece construction.
7. Compressor (1) according to any one of claims 1 to 5,
   characterized in that
   the cylinder head (4) is of multi-part, especially two-part, construction.
8. Compressor (1) according to claim 7,
   characterized in that
   the component which surrounds or accommodates the shaft seal (8) is made of a material having good thermal conductivity, especially of aluminium.
9. Compressor (1) according to any one of the preceding claims,
   characterized by
   a belt pulley (12) is connected to the drive shaft (7) so as to rotate therewith, which belt pulley is arranged on the side of the compressor (1) facing the intake gas chamber (5) and has flow elements (31) which, on rotation of the belt pulley (12), effect a flow of air (32a, 32b) directed towards the cylinder head (4) and the component of the compressor (1) accommodating the shaft seal (8).
10. Compressor (1) according to any one of the preceding claims,
    characterized in that
    the shaft seal chamber (9) is constructed in such a way that when the compressor (1) is at a standstill an oil pool (14) is retained in the shaft seal chamber (9).
11. Compressor (1) according to claim 10,
    characterized in that
    the shaft seal chamber (9) has an oil barrier wall and/or a labyrinth seal and/or a sealing lip (17) for retaining the oil pool (14).
12. Compressor (1) according to claim 10 or 11,
    characterized in that
    the oil pool (14) reaches at least the lower edge (36) of a sealing gap of the shaft seal (8).
13. Compressor (1) according to any one of the preceding claims, especially according to claim 12,
    characterized in that
    all openings and recesses of the shaft seal chamber (9), especially the openings for the connections (33, 34) between shaft seal chamber (9) and intake gas inlet (6) and between shaft seal chamber (9) and intake gas chamber (5), are arranged above the lower edge (36) of the or a sealing gap of the shaft seal (8).
14. Compressor (1) according to any one of the preceding claims,
    characterized in that
    the opening for the connection (33) between shaft seal chamber (9) and intake gas inlet (6) is arranged in the shaft seal chamber in such a way that it is located between lower edge (36) and upper edge (37) of the sealing gap.
15. Compressor (1) according to claim 14,
    characterized in that
    the opening for the connection (33) is located centrally between lower edge (36) and upper edge (37) of the sealing gap.
16. Compressor (1) according to any one of the preceding claims,
    characterized in that
    the openings for the connections (33, 34) between shaft seal chamber (9) and intake gas inlet (6) and between shaft seal chamber (9) and intake gas chamber (5) are arranged at different levels in the shaft seal chamber (9).
17. Compressor (1) according to any one of the preceding claims,
    characterized in that
    the intake gas channel (13) is constructed in such a way that the flow of intake gas emerging therefrom acts chiefly on the/a region of the/a sealing gap of the shaft seal (8) and/or is diverted around the shaft seal (8).
18. Compressor (1) according to any one of claims 7 to 17,
    characterized in that
    a thermal insulator (16) is arranged between at least two components of the cylinder head (4).
19. Compressor (1) according to claim 18,
    characterized in that
    the thermal insulator (16) comprises a steel sheet which is elastomer-coated on one or both sides, that is to say on a side facing the cylinder block (4) and/or on a side remote from the cylinder block (3).
20. Compressor (1) according to any one of the preceding claims,
    characterized in that
    the shaft seal (8) comprises a lip seal or an axial slide ring seal.
21. Compressor (1) according to any one of the preceding claims,
    characterized in that
    cooling fins (30) are arranged on the cylinder head (4).
22. Compressor (1) according to any one of the preceding claims,
    characterized in that
    a non-return valve (15) is arranged in or at the connection (33) of intake gas inlet (6) and shaft seal chamber (9).

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