EP2140142B1 - Gear pump - Google Patents

Abstract

The invention relates to a gear pump having two meshing gear wheels configured of a driven gear wheel and a gear wheel moving along with the same. A rotatably supported drive shaft is provided for driving the gear wheel, the shaft being held in the pump housing by bearing means. A sealing means is associated with the drive shaft at the circumference between the gear wheel and the bearing means, the sealing means comprising a pressure ring resting against a face of the gear wheel. In order to prevent the gear wheel in the pump housing from starting to run, a second sealing means having a second pressure ring is disposed on the opposite face of the gear wheel at the circumference of the drive shaft between a second bearing means and the gear wheel, wherein both pressure rings have a sealing shoulder opposite the gear wheel, the shoulder being pressed against the face of the gear wheel under the action of a spring means.

Description

The invention relates to a gear pump for conveying colored lakes according to the preamble of claim 1.

A generic gear pump is out of the EP 1 280 996 B1 known as the closest prior art. The known gear pump has two meshing gears, which are rotatably supported within a pump housing. One of the gears is coupled to a drive shaft which is mounted in a bearing within the pump housing. The drive shaft penetrates the bearing housing in the pump housing and is coupled outside of the pump housing with a drive. To seal the outwardly driven drive shaft, the gear wheel on the drive shaft is associated with a sealing means which seals the bearing means of the drive shaft relative to a pumping space formed on the circumference of the gear. In this case, the sealing means on a ceramic ring, which is supported under a bias on a front side of the gear.

By this one-sided support of the sealing means on the end face of the gear wheel, the gear with the opposite end face is pressed against the pump housing, so that due to the unbalanced load of the gear uneven sealing gaps are the result. Also, the assumption that takes place during operation an acting on both sides of the gear operating pressure due to the larger opposite end face of the gear, a balance of forces, is not true, since experience shows that over the length of the sealing gaps between two bodies, a pressure drop occurs. The unbalanced load of the gear remains even during operation, so that increased friction between the gear and the pump housing on the opposite side of the sealing means of the gear occur.

From the DE 10 2005 016 670 A1 is another gear pump for conveying and dosing of colored lakes is known, in which at both end faces of the driven gear sealing means are arranged in the pump housing to separate the delivery area within the pump housing from the storage area of the drive shaft. The sealant is in this case formed by a seal and a spring element, which loads the seal with a small force in the direction of the gear. In this case, although a symmetrical loading of the gear on both sides, but with the disadvantage that the seal is disposed in an outer peripheral portion of the gear, so that the seal rubs due to the large diameter with a relatively large contact surface at the end faces of the gear and therefore leads to higher signs of wear. In addition, due to the sealing grooves formed in the pump housing, only relatively small spring elements can be integrated, which according to experience can only produce small spring forces for pressing the seal. In that regard, only limited tightness of the gap between the end faces of the gear and the pump housing can be achieved. Another disadvantage of the known gear pump is given by the fact that the leaks of the sealing points lead directly to the fact that color varnishes gets into the bearing of the drive shaft, which are difficult to remove, especially when flushing.

It is an object of the invention to develop a gear pump of the generic type such that, on the one hand, a seal against the bearings of the drive shaft is achieved on the gear and on the other hand, a good flushability of the pump is maintained.

Another object of the invention is to provide a gear pump of the generic type in which the bearing friction of the drive shaft remains substantially constant during operation.

This object is achieved by a gear pump with the features of claim 1.

Advantageous developments of the invention are defined by the features and feature combinations of the respective subclaims.

The invention has the particular advantage that the driven gear is guided freely in the pump housing and forms a relatively uniform sealing gap to each end face with the pump housing. For this purpose, a second sealing means is arranged with a second pressure ring on the opposite end face of the gear on the circumference of the drive shaft between a second bearing means and the gear, both pressure rings on both faces of the gear each having a sealing shoulder and loading by a spring means on the end faces of the gear are pressed. The gear is stretched between the pressure rings and thus independent of the position of the drive shaft. A tarnishing of one of the end faces on one of the housing plates is thereby avoided and the gearwheel forms for each end face with the pump housing an equally large sealing gap. The prestressed on both sides of the pressure rings and the thus fixed position of the gear allows a high sealing effect, so that the protruding from the pumping chamber color lakes advances only in the lateral sealing gaps only to the sealing shoulders of the pressure rings. The bearing means within the pump housing remain free of color lakes, so that a flushing of the bearing points of the drive shaft is unnecessary. In the design of the storage means thus the requirements of a flushability can be neglected.

In order to prevent even a few paint residues passing the sealing point between the pressure rings and the gear and the pressure rings and the pump housing and reach the bearing means, the development of the invention is preferably used, in which the sealing means each have a sealing ring, which the bearing means to Shield both sides of the gear relative to the pressure rings and each define on the circumference of the drive shaft formed between the pressure ring and the sealing ring washing compartment. The sealing rings, which are arranged on the circumference of the drive shaft and sealingly act between the pump housing and the drive shaft, form a second den Pressure rings downstream seal to separate the bearings of the delivery chamber. As a result, even the residues of the colored lakes entering the washing compartment are kept away from the storage means.

Since the gear pumps used for conveying color varnishes can be flushed to perform color changes, it is provided that each of the flushing chambers is connected by a flushing channel in the pump housing with a flushing connection. Thus, the color varnishes which have entered the rinsing chamber can be rinsed out before a color change by means of a rinsing liquid supplied via the rinsing connection.

In order to be able to flush in particular the forming between the gear and the drive shaft joint gap with a detergent, it is proposed according to a development of the invention to connect the two rinsing chambers by multiple rinsing channels between the drive shaft and the pressure rings and between the drive shaft and the gear ,

Due to the high sealing effect between the bearings and the delivery area of the gear pump can be used for storage of the drive shaft all common storage media. Thus, the bearing means can be performed by bushings for sliding bearing of the drive shaft, but in the case of a bearing lubrication borrowed funds are used. In order to obtain the highest possible service life and operating periods of the gear pump, the bearing means for supporting the drive shaft are preferably formed according to an advantageous embodiment of the invention by at least two rolling bearings whose rolling elements are held in a filled with a lubricant annular chamber. As a lubricant fat fills are preferably used, so that the drive shaft can be driven with relatively low bearing friction.

When promoting color varnishes, for example in paint shops for painting car body parts for vehicles, special care must be taken to ensure that the required amount of color varnishes remains adjustable over the speed of the drive shaft and remains constant during operation when a drive speed is selected. For this It is necessary that the toothed engagement of the driven gear and the revolving gear is provided as possible with little play to avoid tolerance-related fluctuations in delivery. In that regard, the development of the invention, in which the follower gear rotatably connected to a shaft journal which is mounted on both sides of the gear by a plurality of bearing means, particularly advantageous to ensure constant flow rates. Here, a sealing means is provided on the circumference of the shaft journal on both sides of the gear, each having a voltage applied to one of the end sides of the gear pressure ring.

The bearing means of the shaft journal can also be shielded by sealing rings relative to the pressure rings in such a way that no residues of color lakes pollute the bearing means. The sealing rings form with the pressure rings on the circumference of the shaft journal to each end face of the gear each have a flushing chamber, which is connected by a flushing passage in the pump housing with a flushing port. Thus, the leaking at the follower gear through the gaps between the pump housing and the gear leakage after entering the washrooms can be removed by a purge.

To rinse the joint gap between the gear and the shaft journal is also provided that the two rinsing chambers are connected by a plurality of purge channels between the shaft journal and the pressure rings and between the shaft journal and the gear.

The bearing means for supporting the shaft journal are preferably formed identically to the bearing means of the drive shaft. So a plain bearing with bushings would be possible. However, the bearing means for supporting the shaft journal are preferably formed by at least two roller bearings whose rolling elements are held in an annular chamber filled with a lubricant.

On the one hand to minimize the wear of the sealant against the gear and on the other hand, a high sealing effect against the bearing means to obtain, according to the embodiment of the invention, the pressure rings formed of a ceramic material and the sealing rings designed as so-called Nutringc.

For the sealing effect of the sealing points formed between the pressure rings and the gears decisive is the biasing force generated by the spring means, with which a sealing shoulder of the pressure ring is held on the end face of the gear. It is essential that the generated biasing force during the operating life of the pump remains substantially constant. In that regard, has preferably proven as a spring means for Andrückung the pressure rings, the development of the invention, in which the spring means is formed by a respective plate spring assembly. In this case, high spring forces can be generated even in small spaces in the scope of the drive shaft or the shaft journal.

The advantageous development of the invention, in which the end faces of the gears are formed of a ceramic material, has the particular advantage that even with larger biasing forces of the pressure rings no increased signs of wear can occur. In addition, the frictional forces generated between the end faces of the gears and the sealing shoulders made of ceramic pressure rings remain relatively low.

In order to obtain in particular the gap forming between the gear wheels and the pump housing as close as possible to tight tolerances with a high sealing effect, the pump housing is preferably designed in several parts, the end faces of the gear wheels being held between two housing plates. The plate design allows a Feinstbearbeitung of the pump housing, so that a high Planparallclität between the gears and the housing plates is adjustable.

In a further advantageous embodiment of the invention, it is provided to form the drive shaft of a bearing shaft and a coupling shaft connected by a releasable rotational connection with the bearing shaft, wherein the bearing shaft is connected within the pump housing with the gear and is supported by the bearing means. The clutch shaft outside of the pump housing is in contrast mounted rotatably in a support housing by a support bearing and can be coupled at the free end to the drive. Thus, also advantageous to absorb the outer forces acting on the drive shaft forces through the support bearing.

The gear pump according to the invention will be explained in more detail with reference to some embodiments with reference to the accompanying figures.

Fig. 1

schematisch eine Schnittansicht eines ersten Ausführungsbeispiel der erfindungsgemäßen Zahnradpumpe

Fig. 2

schematisch eine Schnittansicht des Wellenzapfens der Ausführungsbei- spiels aus Fig. 3

Fig. 3

schematisch eine Schnittansicht eines weiteren Ausführungsbeispiels der erfindungsgemäßen Zahnradpumpe

Fig. 4

schematisch eine Schnittansicht der Antriebswelle des Ausführungsbei- spiels aus Fig. 1

It represents

Fig. 1

schematically a sectional view of a first embodiment of the gear pump according to the invention

Fig. 2

schematically a sectional view of the shaft journal of the exemplary embodiment of game Fig. 3

Fig. 3

schematically a sectional view of another embodiment of the gear pump according to the invention

Fig. 4

schematically a sectional view of the drive shaft of the exemplary embodiment of game Fig. 1

In Fig. 1 and Fig. 2 a first embodiment of the gear pump according to the invention is shown in a schematic sectional view. Fig. 2 shows only an enlarged section of the Fig. 1 , so that the following description applies to both figures.

The gear pump has a pump housing 1, which is constructed in several parts and the housing plates 1.1 and 1.2 and held between the housing plate 1.1 and 1.2 center plate 1.3 consists. In the end faces of the housing plates 1.1 and 1.2 each have a housing seal 1.4 and 1.5 is arranged, through which the gaps between the middle plate 1.3 and the housing plates 1.1 and 1.2 are sealed to the outside. The middle plate 1.3 has recesses for two intermeshing gears 4 and 5. In the overlapping region of the gears 4 and 5, a delivery channel system 6 is formed in the housing parts, which is connected to a pump inlet 2 formed in the housing plate 1.2 and with a pump outlet 3 formed in the housing plate 1.1. The delivery channel system 6 is preferably formed by bores and recesses in the housing plates 1.1 and 1.2 and the center plate 1.3.

The gear 4 is rotatably connected to a drive shaft 7. For this purpose, the gear 4 is penetrated in a central bore 28 of the drive shaft 7. Between the circumference of the drive shaft 7 and the bore 28 of the gear 4 is a connecting means 29 (shown in phantom), through which a positive and rotationally fixed connection between the drive shaft 7 and the gear 4 is formed. The drive shaft 7 has a bearing end 7.1 within the pump housing 1 and a coupling end 7.2 outside of the pump housing 1. For this purpose, a continuous receiving bore 18 is provided in the housing plate 1.1 and in the housing plate 1.2, which is penetrated substantially coaxially by the drive shaft 7. In the housing plate 1.1 and the housing plate 1.2 is between the circumference of the drive shaft 7 and the receiving bore 18 of the housing plates 1.1 and 1.2, a sealing means 9.1 and 9.2 and a bearing means 8.1 and 8.2 arranged. Each of the sealing means 9.1 and 9.2 in each case has a pressure ring 10.1 and 10.2. The pressure rings 10.1 and 10.2 are held axially displaceable on the circumference of the drive shaft 7 and are supported, each with a sealing shoulder 16.1 and 16.2 on the end faces of the gear 4 from. The pressure rings 10.1 and 10.2 and the end faces of the gear 4 are for this purpose preferably formed of a ceramic material. For this purpose, the gear 4 and the pressure rings 10.1 and 10.2 may also be formed entirely of a ceramic material.

At the opposite to the sealing shoulder 16.1 and 16.2 side of the pressure rings 10.1 and 10.2 each have a spring means 11.1 and 11.2 is arranged. The spring means 11.1, which is formed in this embodiment as a plate spring package, is stretched between a fixed in the housing plate 1.1 retaining ring 17 and the pressure ring 10.1. On the opposite side of the gear 4, the spring means 11.2, which is also designed as a disc spring assembly, between a further fixed in the housing plate 1.2 retaining ring 17 and the pressure ring 10.2 acts.

Furthermore, the sealing means 9.1 and 9.2 on the side facing the bearing means 8.1 and 8.2 side a sealing ring 12.1 and 12.2, which is held between the periphery of the drive shaft 7 and the receiving bore 18 in the housing plate 1.1 and 1.2. The sealing rings 12.1 and 12.2 are formed in this embodiment by grooved rings that generate radially acting sealing forces between the drive shaft 7 and the receiving holes 18.

The sealing rings 12.1 and 12.2 are held at a distance from the pressure rings 10.1 and 10.2 on the circumference of the drive shaft 7, so that in the space between the drive shaft 7 and the receiving bore 18, a washing compartment 13.1 and 13.2 is formed. The washing compartment 13.1 is coupled via a flushing channel 14.1 in the housing plate 1.1 with a flushing connection 15.1. The trained on the opposite side of the gear 4 in the sealing means 9.2 Spülkammer 13.2 is connected via a flushing passage 14.2 in the housing plate 1.2 with a flushing port 15.2. In operation, the flushing connections 15.1 and 15.2 are connected to a flushing system.

The rinsing rooms 13.1 and 13.2 are connected to one another by a plurality of rinsing grooves 36.1 and 36.2. The flushing grooves 36.1 here each denote the flushing groove, which extend between the pressure ring 10.1 and the drive shaft 7 and the pressure rings 10.2 and the drive shaft 7. Here, the flushing groove 36.1 may be formed by a groove on the circumference of the drive shaft or by a groove on the inner diameter of the pressure ring. The flushing groove 36.2 denotes a connection between the end faces of the gear 4, wherein this through a groove in the bore 28th of the gear 4 or by a groove on the circumference of the drive shaft 7 may be executed.

For storage of the drive means, the bearing means 8.1 and 8.2 respectively in the outer regions of the housing plates 1.1 and 1.2 are arranged. The bearing means 8.1 and 8.2 are each formed by rolling bearings 32, which has a plurality of rolling elements 30 which are held in a closed annular chamber 31 between an inner and an outer race. For this purpose, the roller bearings 32 are held in the axial direction by a respective retaining ring 17 fixed in the housing plate 1.1 and 1.2. As a lubricant, the closed annular chamber 31 is preferably a grease filling, which preferably ensures the lubrication of the rolling elements during the service life of the gear pump.

The receiving bore 18 in the housing plate 1.1 is closed to the outside by a cover 27. On the opposite drive side of the pump housing 1, the coupling end 7.2 of the drive shaft 7 protrudes from the receiving bore 18 of the housing plate 1.2 out. The coupling end 7.2 of the drive shaft 7 has in the end region a diameter shoulder 33 on which a support ring 20 rests. The support ring 20 is L-shaped and is held in a recess of a support housing 19.

The support housing 19 has a recess 21, which is completely penetrated by the drive shaft 7, so that the free coupling end 7.2 of the drive shaft 7 protrudes to connect a drive from the support housing 19. The support housing 19 is fixedly connected to the pump housing 1.

The driven by the drive shaft 7 gear 4 is in engagement with the gear 5, which is held freely rotatably between the housing plates 1.1 and 1.2 in the middle plate 13. The gear 5 is held with its bore on a bearing journal 34. The bearing pin 34 is not supported in the housing plates 1.1 and 1.2 in this example, so that the gear 5 only through the housing plates 1.1 and 1.2 and guided by the center plate 1.3 and is driven by the gear 4.

At the in Fig. 1 illustrated gear pump, the gear 4 is driven by the drive shaft 7 in promoting a paint color. A paint supplied via the pump inlet 2 is conveyed to the pump outlet 3 under pressure by the meshing gears 4 and 5 in the delivery channel system 6. The leaking from the delivery channel 6 via the gaps between the end faces of the gears 4 and 5 and the Gchäuseplatten 1.1 and 1.2 leakage is held at the end faces of the gear 4 under bias pressure rings 10.1 and 10.2, so that the joint gap between the gear 4 and the drive shaft 7 remains substantially free of leaks.

The leaking possibly through gaps between the pressure ring 10.1 and 10.2 and the housing plates 1.1 and 1.2 is absorbed by the clearances 13.1 and 13.2. By the pressure rings 10.1 and 10.2 associated sealing rings 12.1 and 12.2 is a hermetic seal against the bearing means 8.1 and 8.2, so that no leakage can occur in the bearing means 8.1 and 8.2.

In order to free the leakages with paint residues from the washing rooms 13.1 and 13.2 and the gaps between the gear 4 and the drive shaft 7 in a color change, a rinsing liquid is introduced into the pump housing via the flushing connections 15.1 and 15.2 and the spaces between the drive shaft 7. den Housing plates 1.1 and 1.2 and rinsed in the gear 4. The delivery channel system 6 within the pump housing is also flushed by means of a flushing liquid through the pump inlet 2 and the pump outlet 3, so that the gaps between the gears 4 and the housing plates 1.1 and 1.2 and the center plate 1.3 can be flushed.

In Fig. 3 and Fig. 4 is a further embodiment of the gear pump according to the invention shown schematically in a cross-sectional view. The embodiment is in the construction of the gear pair of the gears 4 and 5 and the pump housing 1 is substantially identical to the embodiment according to Fig. 1 , so that reference is made to the above description at this point and only the differences will be explained. The components with the same functions have been given identical reference numerals. It also provides Fig. 4 only an enlarged view of a section of Fig. 3 so that the following description applies to both figures.

The rotatably connected to the gear 4 drive shaft 7 is formed in this embodiment by a bearing shaft 25 and a coupling shaft 26 which are interconnected by a rotary joint 24. The bearing shaft 25 is rotatably supported by the bearing means 8.1 and 8.2 in the receiving bores 18 of the housing plates 1.1 and 1.2. The bearing means 8.1 and 8.2 associated sealing means 9.1 and 9.2 on the circumference of the bearing shaft 25 and the bearing means 8.1 and 8.2 are identical to the previous embodiment, so that reference can be made to the preceding description.

The bearing shaft 25 extends substantially over the width of the housing plates 1.1 and 1.2, wherein on the drive side, the bearing shaft 25 is coupled to the coupling shaft 26. For this purpose, 26 projections are formed at the ends of the bearing shaft 25 and the coupling shaft, which constitute the rotary joint 24.

The coupling shaft 26 is rotatably supported by a support bearing 22 in a support housing 19. The coupling shaft 26 is held in the support housing 19 both in the axial direction and in the radial direction by the support bearing 22. The coupling shaft 26 has a free protruding from the support housing 19 end, which is coupled with a drive (not shown here).

The follower gear 5 is rotatably connected to the circumference of a shaft journal 23 with this. The shaft journal 23 penetrates the bore of the Gear 5 and is held supported on both sides of the gear 5 in receiving bores 35 of the housing plate 1.1 and the housing plate 1.2. At the periphery of the shaft journal 23, the bearing means 8.3 and 8.4 are provided on both sides of the gear 5 for this purpose. The bearing means 8.3 and 8.4 are formed by roller bearings 32, which is identical in construction to the rolling bearings 32 which support the drive shaft 7. In that regard, each of the bearings 32 has a plurality of rolling elements 30, which are held in a closed annular chamber 31, each with a grease filling.

To seal the bearing means 8.3 and 8.4, the sealing means 9.3 and 9.4 are provided on the circumference of the shaft journal 23 between the gear 5 and the bearing means 8.3 and 8.4. The sealing means 9.3 and 9.4 are identical in their construction, wherein each of the sealing means 9.3 and 9.4 each have a pressure ring 10.3 and 10.4. The pressure rings 10.3 and 10.4 are held by spring means 11.3 and 11.4 under bias on the end faces of the gear 5. For this purpose, each pressure ring 10.3 and 10.4 each have a sealing shoulder 16.3 and 16.4, which are supported on the end faces of the gear 5.

The spring means 11.3 and 11.4 are formed in this embodiment by Tel-lerfederpakete which are fixed by retaining rings 17 in the receiving bore 35.

At a distance from the pressure rings 10.1 and 10.2, the sealing rings 12.3 and 12.4 are assigned to the bearing means 8.3 and 8.4 at the periphery of the shaft journal 23, wherein the sealing rings 12.3 and 12.4 are formed as grooved rings, the annular space between the shaft journal 23 and the receiving bore 35 after Seal the outside. Between the pressure ring 10.3 and the sealing ring 12.3 and between the pressure ring 10.4 and the sealing ring 12.4, a flushing space 13.3 and 13.4 is formed in each case on the circumference of the shaft journal 23. The rinsing chambers 13.3 and 13.4 are in each case by a flushing passage 14.3 in the housing plate 1.1 and a flushing passage 14.4 in the housing plate 1.2 with a flushing port 15.3 the housing plate 1.1 and a flushing port 15.4 connected to the housing plate 1.2.

The receiving bore 35 is closed in the housing plate 1.1 and in the housing plate 1.2 each outwardly by a cover 27.

At the in Fig. 3 and 4 illustrated embodiment takes place during operation, the sealing of the bearing points of the shaft journal 23 in the pump housing 1 analogous to the drive shaft according to the embodiment according to Fig. 1 , Thus, the follower gear 5 is also stretched between two pressure rings 10.3 and 10.4, wherein the pressure rings 10.3 and 10.4 are also preferably formed of a ceramic material and wherein at least the frontal region of the gear 5, against which the sealing shoulders 16.3 and 16.4 with bias, also are formed of a ceramic material. Preferably, in the in Fig. 3 illustrated embodiment, the gears 4 and 5 made of a full ceramic or ceramic-coated side edges. As a result, ceramic material pairings can be used to make on the end faces of the gears 4 and 5, the sealing points generated by the pressure rings 10.1 to 10.4.

The in the FIGS. 1 to 4 illustrated embodiments are exemplary in construction and arrangement of the bearing means for supporting the drive shaft and the shaft journal. In principle, the rolling bearings can alternatively be replaced by plain bearings or other common storage means. Likewise, the purge channels and flushing connections shown are optional. So rinses on the gear pumps can also be performed on the existing pump connections and the existing gaps between shafts, gears and housing parts. In that case, no additional purge channels would be required.

LIST OF REFERENCE NUMBERS

1

pump housing

1.1

housing plate

1.2

housing plate

1.3

center plate

1.4

housing seal

1.5

housing seal

2

pump inlet

3

pump outlet

4

Gear (driven)

5

Gear (running)

6

Feed channel system

7

drive shaft

7.1

bearing end

7.2

coupling end

8.1, 8.2, 8.3, 8.4

bearing means

9.1, 9.2, 9.3, 9.4

sealant

10.1, 10.2, 10.3, 10.4

pressure ring

11.1, 11.2, 11.3, 11.4

spring means

12.1, 12.2, 12.3, 12.4

seal

13.1, 13.2, 13.3, 13.4

Wash cabinet

14.1, 14.2, 14.4, 14.5

irrigation channel

15.1, 15.2, 15.3, 15.4

flushing connection

16.1, 16.2, 16.3, 16.4

sealing switch

18

location hole

19

support housing

20

support ring

21

recess

22

storage support

23

shaft journal

24

pressure connection

25

bearing shaft

26

clutch shaft

27

cover

28

drilling

29

connecting means

30

rolling elements

31

annular chamber

32

roller bearing

33

Diameter paragraph

34

pivot

35

location hole

36.1, 36.2

scavenging groove

Claims (15)

1. Gear pump with two meshing gears (4, 5) to convey paints, which are formed from a driven gear (4) and an idling gear (5), with at least one drive shaft (7) mounted to rotate, which is splined to the driven gear (4) and is held by bearings (8.2) in pump housing (1), in which the drive shaft (7) can be connected to a drive and in which a seal (9.2) is assigned to drive shaft (7) on the periphery between gear (4) and bearing (8.2), which includes a pressure ring (10.2) lying against one face of gear (4), characterized by the fact that a second seal (9.1) with a second pressure ring (10.1) is arranged on the opposite face of gear (4) on the periphery of the drive shaft (7) between a second bearing (8.1) and the gear (4) and that both pressure rings (10.1, 10.2) have a sealing shoulder (16.1, 16.2) opposite gear (4), each of which is forced against the face of gear (4) by a spring device (11.1, 11.2).
2. Gear pump according to Claim 1, characterized by the fact that the seals (9.1, 9.2) each have a sealing ring (12.1, 12.2) and that the sealing rings (12.1, 12.2) shield the bearings (8.1, 8.2) on both sides of gear (4) relative to pressure rings (10.1, 10.2) and delimit on the periphery of drive shaft (7) a rinsing space (13.1, 13.2) formed between the pressure ring (10.1, 10.2) and the sealing ring (12.1, 12.2).
3. Gear pump according to Claim 2, characterized by the fact that each of the rinsing spaces (13.1, 13.2) is connected by a rinsing channel (14.1, 14.2) in the pump housing (1) to a rinsing connection (15.1, 15.2).
4. Gear pump according to Claim 2 or 3, characterized by the fact that the two rinsing stations (13.1, 13.2) are connected to each other via several rinsing grooves (36.1, 36.2) between drive shaft (7) and pressure rings (12.1, 12.2) and between drive shaft (7) and gear (4).
5. Gear pump according to one of Claims 1 to 4, characterized by the fact that the bearings (8.1, 8.2) are formed to support the drive shaft (7) by at least two roller bearings (32) whose roller bodies (30) are held in an annular chamber (31) filled with a lubricant.
6. Gear pump according to one of Claims 1 to 5, characterized by the fact that the idling gear (5) is splined to a shaft pin (23), which is supported on both sides of gear (5) by several bearings (8.3, 8.4) and that a seal (9.3, 9.4) is arranged on both sides of gear (5) on the periphery of shaft pin (23), each of which has a pressure ring (10.3, 10.4) lying against the face of gear (5).
7. Gear pump according to Claim 6, characterized by the fact that the seals (9.3, 9.4) each have a sealing ring (12.3, 12.4) and that the sealing rings (12.3, 12.4) shield the bearings (8.3, 8.4) on both sides of gear (5) relative to pressure rings (10.3, 10.4) and delimit a rinsing space (13.3, 13.4) formed on the periphery of shaft pin (23) between the pressure ring and sealing ring (10.3, 10.4).
8. Gear pump according to Claim 7, characterized by the fact that each of the rinsing spaces (13.3, 13.4) is connected via a rinsing channel (14.3, 14.4) in pump housing (1) to a rinsing connection (15.3, 15.4).
9. Gear pump according to Claim 7 or 8, characterized by the fact that the two rinsing spaces (13.3, 13.4) are connected to each other via several rinsing grooves (36.1, 36.2) between the shaft pin (23) and the pressure rings (10.3, 10.4) and between the shaft pin (23) and gear (5).
10. Gear pump according to one of Claims 6 to 9, characterized by the fact that the bearings (8.3, 8.4) are formed to support the shaft pin (23) through at least two roller bearings (23) whose roller bodies (30) are held in annular chamber (31) filled with lubricant.
11. Gear pump according to one of the aforementioned claims, characterized by the fact that the pressure rings (10.1-10.4) are formed from a ceramic material and that sealing rings (12.1-12.4) are each designed as a groove ring.
12. Gear pump according to one of the aforementioned claims, characterized by the fact that the spring devices (11.1-11.4) for pressing the pressure rings (10.1-10.4) are each formed from a belleville spring stack.
13. Gear pump according to one of Claims 1 to 12, characterized by the fact that the faces of gears (4, 5) are formed from a ceramic material.
14. Gear pump according to one of Claims 1 to 13, characterized by the fact that the drive shaft (7) is formed from a bearing shaft (25) and a coupling shaft (26) connected by a releasable rotary connection (24) to bearing shaft (25), that the bearing shaft (25) is connected to gear (4) within pump housing (1) and is supported by the bearings (8.1, 8.2) and that the coupling shaft (26) is mounted to rotate outside of pump housing (1) in a support housing (19) through a support bearing (22) and can be connected to a drive on the free end.
15. Gear pump according to Claim 14, characterized by the fact that the support housing (19) is firmly connected to pump housing (1) and is penetrated by the drive shaft in a recess (21).

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