EP2122175B1 - Gear wheel pump - Google Patents

Description

The invention relates to a gear pump, in particular for conveying colored paints according to the preamble of claim 1.

A generic gear pump is out of the DE 10 2005 016 670 A1 known. The known gear pump has two meshing gears, which are rotatably mounted within a pump housing by a drive shaft and a bearing pin. Together with a pump inlet and a pump outlet, the gears within the pump housing form a delivery channel system to deliver a colored lake in liquid or powder form. In order to avoid that paint residues on the gaps formed between the pump housing and the gears emerge from the conveyor channel system and spread over the gaps within the pump housing, seals are provided between the end faces of the gears and the pump housing. In addition, a Spülkanalsystem is formed within the pump housing to flush out in a color change possible paint residues from the gaps between the pump housing, the gears, the drive shaft and the bearing pin.

The known gear pump can already be seen from the combination of front side seals of the gears and downstream Spülkanalsystemen that such sealing systems are subject to increased wear due to a constant friction. In that regard, only limited tightness of the gap on the front sides of the gears relative to the stationary pump housings can be achieved. In addition, higher sealing forces in the face area of the gears would only lead to unwanted increase in drive power.

Another problem with the known in the prior art gear pump is given by the fact that in the gap between the drive shaft and the gear arranged connecting means dead spaces are created, which can be freed by rinsing insufficient paint residues. Due to the rotational movement of the drive shaft and the gearwheel, however, such color residues can unintentionally propagate, so that undesired contaminants can not be ruled out.

From the EP 1 164 293 A2 For example, a gear pump is known in which the delivery channel system and the scavenger system within the pump housing are connected solely by the gaps between the pump housing, the gears of the drive shaft and the journal. In that regard, the paint residues that have entered the column can be removed by intensive rinsing. In the known gear pump, the drive shaft is connected via a press fit with the gear, which, however, makes it difficult to disassemble and assemble easily between the drive shaft and the gear.

It is an object of the invention to develop a gear pump of the generic type such that the column in communication with the conveying channel in the pump housing are easily flushed.

Another object of the invention is to provide a gear pump of the generic type in which the assembly and disassembly options are maintained even after prolonged periods of operation.

This object is achieved in that the gap between the drive shaft and the gear is sealed by a sealant to the end faces of the gear.

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

The invention has the particular advantage that the hard to reach area for cleaning between the drive shaft and the gear is kept free of paint residues. The connecting means provided between the toothed wheel and the drive shaft can thus be made removable, without resulting in unwanted poorly flushable dead spaces. By sealing the connection point between the gear and the drive shaft, the positive connections remain in a predefined manner. Gluing the connecting means between the drive shaft and the gear due to paint residues or other media can not occur. The connection between the drive shaft and the gear can therefore be easily solved during maintenance.

In order to obtain a uniform sealing of the gap between the drive shaft and the gear towards the end faces, the sealing means is preferably formed by two spaced sealing rings on the circumference of the drive shaft, wherein the distance between the sealing rings is equal to or smaller than the width of the gear. Thus, the gap can be sealed substantially over the full width of the gear, so that essentially no or only small transition regions of the gap remain accessible.

Depending on the arrangement of the sealing rings, which can be held both in radially circumferential sealing grooves in the periphery of the drive shaft and / or in radially circumferential sealing grooves in the periphery of a bore of the gear, the sealing surfaces can be both on the circumference of the drive shaft and in the bore portions of the gear realize.

Particularly preferred is the development of the invention, in which between the drive shaft and the gear a plurality of diameter stages are formed, wherein in one of the diameter stages, the connecting means between the drive shaft and the gear is held. This allows the surfaces to Separate sealing function and the surfaces for receiving fasteners from each other. In addition, this allows simple assembly and disassembly work, which are carried out between the gear and the drive shaft, without sealing surfaces are influenced in this case.

Preferably, the sealing rings are held in the diameter steps between the drive shaft and the gear wheel, which enclose the diameter step for receiving the connecting means.

In order to obtain a rotationally fixed connection between the drive shaft and the gear, the variant of the invention is preferably used, in which the connecting means is formed by a pin which is fixedly connected to the drive shaft and which engages in a forming groove of the gear. This allows high torques to be transferred safely.

The shaping groove of the toothed wheel is preferably introduced into a bore shoulder of the toothed wheel formed between two diameters. The pin secured in the drive shaft can thus be guided by simple insertion into the forming groove, so that the assembly of the gear and the drive shaft can be executed without much effort.

Alternatively, however, it is also possible to form the connecting means by a polygonal shape of the drive shaft, which cooperates with a polygonal shape of the bore of the gear. Here, the polygonal shape is preferably introduced in the middle diameter stage of the drive shaft or the gear hole. This development of the invention is particularly suitable for applying the highest possible torques.

However, regardless of the design of the drive shaft and the gear bore, it is also possible to form the connecting means with at least one faulty latch which is held on the circumference of the drive shaft and engages in a recess of the gear bore. Both stepped and non-stepped drive shaft can be used here.

In a particularly preferred embodiment of the invention, a flushing channel system is formed by a plurality of flushing channels, through which the bearing point of the drive shaft can be flushed over its length in each case from outside to inside. The flushing fluid flowing from the outside inwards thus leads the paint residues back into the interior of the pump in order to flush them outward via the pump inlet or the pump outlet. This development is particularly suitable for gear pumps that are used in paint shops with frequent color changes. The flushing system allows fast and intensive cleaning of the gear pump without any disassembly.

In particular, to keep the forming between the gears and the pump housing gap as close as possible to tight tolerances with high sealing effect, according to a preferred embodiment of the invention, the pump housing is formed in several parts, wherein the end faces of the gears are held between two housing plates and wherein the drive shaft with at least a shaft portion is rotatably supported directly on the receiving bore of the housing plate. The plate design allows a Feinstbearbeitung of the pump housing, so that a high plane parallelism between the gears and the housing plates is adjustable.

To realize a particularly compact design, a seal housing is pressure-tight associated with the pump housing, which is penetrated by a concentric to the drive shaft recess of the drive shaft and which encloses a arranged on the circumference of the drive shaft sealant according to an advantageous embodiment of the invention. Thus, the housing plate used for supporting the drive shaft can be made narrow in accordance with the storage requirements. The sealants can get involved connect directly to the circumference of the drive shaft and are held by the seal housing sealingly on the housing plate.

As a sealant advantageously a gland packing and a tensioning means is used, which acts on the packing gland. This can be a seal against high operating pressures within the pump housing realize. In particular, this also returns the respective color paint are possible to initiate, for example, a color change. For this purpose, the drive shaft can be driven with changing direction of rotation.

In a further advantageous embodiment of the invention it is provided that is formed on a protruding outside of the pump housing coupling portion of the drive shaft, a support bearing for radial and axial support of the drive shaft, which is formed by a support ring or a rolling bearing. The support ring or the rolling bearing are preferably held between a support housing and a shaft shoulder of the drive shaft. The support housing is fixedly connected to the pump housing, wherein the seals for sealing the column caused by the drive shaft in the support housing or an upstream seal housing are arranged. This development is characterized in that both internal pressure forces and the forces acting from the outside on the drive shaft can advantageously be absorbed outside the pump housing by a separate support bearing. The axial support of the drive shaft can advantageously absorb the pressure forces acting on the drive shaft; so that the attached to the drive shaft gear can be performed at the end faces substantially wear-free to the pump housing. This increases the service life, since the wear on the gears is significantly reduced.

In order to avoid accumulations of colored lakes in annular gaps outside the pump housing with increasing operating time due to minimal leakage, according to a preferred embodiment of the invention within the support housing a shaft seal arranged on the circumference of the drive shaft and filled in the formed between the sealant and the shaft seal annulus at the periphery of the drive shaft, a barrier liquid. As a barrier liquid in this case, for example, a solvent-containing fluid is used. Here, the development of the invention is particularly advantageous, in which the annular space is connected via separate guide channels with an inlet and an outlet, wherein the inlet and the outlet are formed on the seal housing. Thus, the gaps between the drive shaft and the housing parts can be advantageously rinse after replacement of the barrier fluid.

The development of the invention, in which a circumferential pass bar is formed on the circumference of the bore of the gear or on the circumference of the drive shaft through which the gear is held without play on the drive shaft, has led in particular to improve the startup behavior of the gear to the housing plates. Thus, an additional degree of freedom for the execution of a compensating movement on the gear can be realized by the size and position of the connecting web.

The fitting web is preferably arranged in the middle region of the gear wheel and executed with a fitting length of less than one quarter of the gear width. This makes it possible to realize a pendulum movement in the axial direction of the gear, which leads via the respective end faces associated sealing rings to an automatic centering of the gear and the drive shaft. However, manufacturing tolerances can be completely compensated for this and a wear-resistant and favorable start-up behavior of the gear end face relative to the housing plates can be realized.

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 Ansicht eines ersten Ausführungsbeispiel der erfindungsgemäßen Zahnradpumpe

Fig. 2

schematisch eine Schnittansicht des Ausführungsbeispiel der erfindungsgemäßen Zahnradpumpe nach Fig. 1

Fig. 3

schematisch eine Schnittansicht eines weiteren Ausführungsbeispiels der erfindungsgemäßen Zahnradpumpe

Fig. 4 und Fig. 5

schematisch mehrere Schnittansichten eines weiteren Ausführungsbeispiels der erfindungsgemäßen Zahnradpumpe.

Fig. 6

schematisch eine Schnittansicht eines weiteren Ausführungsbeispiels der erfindungsgemäßen Zahnradpumpe

It represents

Fig. 1

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

Fig. 2

schematically a sectional view of the embodiment of the gear pump according to the invention Fig. 1

Fig. 3

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

4 and FIG. 5

schematically several sectional views of another embodiment of the gear pump according to the invention.

Fig. 6

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

In Fig. 1 and Fig. 2 a first embodiment of the gear pump according to the invention is shown. The Fig. 1 shows a view of the gear pump and in Fig. 2 a cross-sectional view of the gear pump is shown. Unless an explicit reference is made to one of the figures, 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 plates 1.1 and 1.2 middle plate 1.3 consists. In the end faces of the housing plates 1.1 and 1.2 each have a sealing ring 1.4 and 1.5 are 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 with a pump inlet 2 formed in the housing plate 2 and with a likewise in the housing plate 1.2 trained pump outlet 3 is connected. 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 5 is rotatably mounted on a fixed bearing pin 21. The bearing pin 21 is held for this purpose in a press bore 22 in the housing plate 1.1. Between the housing plate 1.1 and the bearing pin 21, a sealing ring 1.6 is provided.

The second gear 4 is rotatably connected to a drive shaft 7. For this purpose, the gear 4 is penetrated in a central bore 12 of the drive shaft 7. Between the circumference of the drive shaft 7 and the bore 12 of the gear 4, a connecting means 9 is provided, through which a positive and rotationally fixed connection between the drive shaft 7 and the gear 4 is formed.

In this embodiment of the gear pump according to the invention, the connecting means 9 is formed by a catch 10. For this purpose, the catch 10 has at several points of the circumference of the drive shaft 7 a locking body 10.1, which is let into a shaft recess 11 and which is tensioned with a spring 10.2 acting radially outward. In the in Fig. 2 shown operating position of the locking body 10.1 is held by the spring 10.2 in a recess 13 of the bore 12 of the gear 4. The recess 13 in the bore 12 of the gear 4 is adapted to the locking body 10.1, so that upon rotation of the drive shaft 7, the gear 4 is driven. In the embodiment shown, the detent 10 is formed by two offset by 180 ° on the circumference of the drive shaft arranged detent body 10.1.

For this purpose, the drive shaft 7 has a bearing end 7.1 and a coupling end 7.2. The bearing end 7.1 of the drive shaft 7 is rotatably mounted within the pump housing. The coupling end 7.2 of the drive shaft 7 protrudes outside of Pump housing 1 for coupling to a drive, not shown here. The bearing end 7.1 of the drive shaft 7 is held with a free end in a bearing bag bore 16 on the housing plate 1.1 and forms a first bearing 8.1. On the opposite side of the gear 4, the drive shaft 7 is rotatably supported in the housing plate 1.2 in a continuous bearing bore 17 in a second bearing 8.2. To the outside of the housing plate 1.2 out a shaft seal 20 is provided outside of the bearing 8.2 between the drive shaft 7 and the housing plate 1.2, so that the free coupling end 7.2 of the drive shaft 7 is pressure-tight out to a drive. Between the bearing 8.2 and the shaft seal 20, a diameter shoulder is formed in the drive shaft 7.

Between the rotating within the pump housing 1 components such as the drive shaft 7, the gear 4 and the gear 5 and the non-rotating components such as the housing plates 1.1 and 1.2 and the bearing pin 21 gaps are each formed directly or indirectly connected to the conveyor channel system 6 are. Such gaps within the pump housing 1 allow a slight leakage of the subsidized paint, depending on the design of the gap seals, which penetrates in particular into the gaps between the gears 4 and 5 and the housing plates 1.1 and 1.2. In order to prevent ingress of leaks in the gap formed between the drive shaft 7 and the gear 4 during operation, 7 sealant 14.1 and 14.2 are provided on the circumference of the drive shaft, which seal the gap between the gear 4 and the drive shaft 7. The sealing means are in particular designed such that the connection means 9 provided between the gear 4 and the drive shaft 7 is located in a completely sealed area inside the pump housing 1. The sealing means is formed in this embodiment by two spaced-apart sealing rings 14.1 and 14.2. The sealing rings 14.1 and 14.2 are each held in sealing grooves 15.1 and 15.2, which are introduced radially circumferentially in the bore 12 of the gear 4. The sealing grooves 15.1 and 15.2 are the associated with respective end faces of the gear 4, so that the gap formed between the drive shaft 7 and the gear 4 is sealed substantially over its entire width. Basically, however, there is also the possibility that the sealing rings 14.1 and 14.2 are assigned directly to the end faces of the gear 4, so that the distance between the sealing rings 14.1 and 14.2 is substantially equal to the width of the gear 4.

In addition to the operational delivery channel system 6, an additional scavenging system is formed within the pump housing with a plurality of flushing channels in the housing plates 1.1 and 1.2 and in the drive shaft 7 and the bearing pin 21 to a supplied from the outside via a closable inlet 19 rinsing agent for rinsing the gaps between to flush the rotating and stationary components within the pump housing 1. Such a scavenging system in a gear pump is for example from the EP 1 164 293 B1 known, so that at this point express reference to the description given there can be taken.

At the in Fig. 2 illustrated embodiment, the inlet 19 opens into a recess of the bearing bag bore 16. From the bearing bag bore 16, the rinsing agent is guided directly through a groove formed as a flushing channel 18.1 to the gap formed in the bearing 8.1 between the drive shaft 7 and the housing plate 1.1. In this case, the bearing 8.1 is flowed through from the outside to the inside of the detergent. The second formed in the housing plate 1.2 8.2 bearing is connected via the flushing channels 18.2, 18.3 and 18.4 with the inlet 19. The flushing channels 18.2 and 18.3 are formed as bores within the drive shaft 7 in order to feed the flushing agent into an annular space formed between the shaft sealing ring 20 and the bearing point 8.2. The flushing channel 18.4 is formed as a groove on the circumference of the drive shaft 7 and extends over the entire bearing point 8.2, so that the rinsing agent the bearing point 8.2 from the outside flows through inside. By arranged on the circumference of the drive shaft sealing rings 14.1 and 14.2 further penetration of the detergent in the gaps is prevented. About the formed between the end faces of the gear 4 and the housing plates 1.1 and 1.2 column, the detergent is performed in the conveyor channel system 6. Thus, the outlet of the flushing agent via the pump inlet 2 and the pump outlet 3 can be realized.

For flushing the bearing gap formed between the bearing pin 21 and the gear 5 further Spülkanäle 18.5, 18.6, 18.7 and 18.8 are provided. The flushing channels 18.5, 18.6 and 18.7 are formed by bores in the housing plate 1.1 and the bearing pin 21 to connect the gap formed between the gear 5 and the bearing pin 21 with the inlet 19. The flushing channel 18.8 is formed as an axially extending groove in the gear hole of the gear 5, so that the entire bearing area of the gear 5 is flushed through.

This in Fig. 1 and 2 illustrated embodiment of the gear pump according to the invention is particularly suitable to promote in Lackieranlagen color lakes, in which frequent color changes to change the color are required. Due to the design of the column and flushing channels all areas of the gear pumps are easily accessible before a color change to flush out paint residues.

In Fig. 3 is a further embodiment of the gear pump according to the invention shown in a cross-sectional view. The embodiment according to Fig. 3 also has a multi-part pump housing 1, which is formed by the housing plates 1.1 and 1.2 and the center plate 1.3 and a seal housing 26. The seal housing 26 is pressure-tightly connected to the housing plate 1.2. Between the housing plates 1.1 and 1.2, the gears 4 and 5 are held in a recess of the center plate 1.3. The pump inlet 2 is in the housing plate 1.2 and the pump outlet 3 opposite in the housing plate 1.1 trained. Here, the conveying channel system 6 forming holes in the housing plate 1.2 and 1.1 are introduced.

The gears 4 and 5 are held between the housing plates 1.1 and 1.2. Here, the driven gear 4 is coupled directly to the bearing end 7.1 to a drive shaft 7. The drive shaft 7 and the bore 12 of the gear 4 have a plurality of diameter stages 23.1 and 23.2. In the transition region of the diameter stages 23.1 and 23.2, an axially extending forming groove 25 is provided within the bore 12, in which a pin 24 of the drive shaft 7 engages. The pin 24 is for this purpose firmly connected to the drive shaft 7 and projects beyond the circumference of the diameter step 23.1 addition. The provided in the bore 12 of the gear 4 Formnut 25 and attached to the periphery of the drive shaft 7 pin 24 in this case form the connecting means 9 in order to obtain a non-rotatable positive connection between the drive shaft 7 and the gear 4.

For sealing the gaps formed between the drive shaft 7 and the gear 5, two spaced sealing rings 14.1 and 14.2 are provided. The sealing ring 14.1 is held in this case in the diameter stage 23.1 in a circumferential groove 12 in the bore 15.1. By contrast, the sealing ring 14.2 is held in the diameter step 23.2 in a sealing groove 15.2 on the circumference of the drive shaft 7.

The drive shaft 7 penetrates the housing plate 1.2 in a bearing bore 17 and forms a bearing 8 of the drive shaft 7. In the course of the drive shaft 7 penetrates the seal housing 26. Within the seal housing 26 is concentric with the bearing bore 17 at the periphery of the drive shaft 7, a shaft seal in shape a gland packing 27 arranged. The gland packing 27 is biased on one side by a clamping means 28 in the axial direction and pressed against the housing plate 1.2. The clamping means 28 in the form of a spring is a clamping sleeve 29 on the circumference of the drive shaft 7 held and fixed relative to the sealing housing 26. The coupling end 7.2 of the drive shaft 7 is shown cantilevered. At the end of the clamping bush 28, a shaft seal 39 is provided.

The meshing with the driven gear 4 gear 5 is held on the journal 21. The bearing pin 21 has a smaller width in relation to the gear 5 and is firmly pressed into the bore of the gear 5, so that the gear 5 is guided only through the housing plates 1.1 and 1.2 and through the center plate 1.3 and driven by the gear 4 becomes.

At the in Fig. 3 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 housing plates 1.1 and 1.2 leakage is held by the arranged between the drive shaft 7 and the gear 4 sealant 14.1 and 14.2, so that the gaps between the gear 4th and the drive shaft 7 in particular in the region of the connecting means 9 remains free of leaks.

In order to free the gaps in the pump housing from paint residues during a color change, it is also possible to use the in Fig. 3 illustrated gear pump with a scavenging system run. In this case, in particular, the gap formed in the bearing 8 between the drive shaft 7 and the housing plate 1.2 and the gaps formed between the end faces of the gears 4 and 5 and the housing plates 1.1 and 1.2 would be flushed through by a rinsing agent. Preferably, the scavenging system would be connected via a separate inlet and flushing channels with the conveyor channel system.

In Fig. 4 and Fig. 5 is shown a further embodiment of the gear pump according to the invention. The following description applies to both figures, insofar as no explicit reference is made to one of the figures. In Fig. 4 the gear pump is shown schematically in a cross-sectional view. Fig. 5 shows a section of the cross-sectional view of the connection between the gear and the drive shaft.

The embodiment is in the structure 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 and 2 , so that reference is made to the above description at this point and only the differences will be explained.

The drive shaft 7 is rotatably supported via bearing bushes 31.1 and 31.2 in the bearing bag bore 16 of the housing plate 1.1 and in the bearing bore 17 of the housing plate 1.2. Between the housing plates 1.1 and 1.2, the driven gear 4 is connected to one another at the bearing end 7.1 of the drive shaft 7 via a connecting means 9. The housing plate 1.1, the center plate 1.3 and the housing plate 1.2 are pressure-tightly connected to each other, wherein on the housing plate 1.2 a pump inlet 2 and the housing plate 1.1 a pump outlet (not shown here) are formed, which are interconnected within the pump housing 1 via a conveyor channel system 6 are.

The follower gear 5 is mounted on the bearing bush 31.3 on the circumference of the journal 21. The bearing pin 21 is held in the press bore 22 of the housing plate 1.1.

The connecting means 9 between the drive shaft 7 and the gear 4 is formed by a polygonal shape 30. For this purpose, the bore 12 of the gear 4 and the circumference of the drive shaft 7 is stepped in several diameter steps. A first extending from the bearing end 7.1 diameter stage 23.1 is designed as a sealing surface, wherein a circumferential sealing groove 15.1 on the circumference of the drive shaft 7 cooperates with a corresponding sealing surface on the bore 12 of the gear 4.

In a mean diameter stage 23.2, a polygonal shape 30 is formed on the circumference of the drive shaft 7 and in the bore 12. The polygonal shape 30 is in Fig. 5 shown schematically. Here, the polygonal shape 30 is exemplified by a hexagon.

As in Fig. 4 is shown, a second sealing surface between the gear 4 and the drive shaft 7 is formed in a diameter larger diameter stage 23.3. For this purpose, the sealing groove 15.2 is formed on the circumference of the drive shaft 7, in which the sealing ring 14.2 is held. The sealing ring 14.2 is supported on an opposite sealing surface of the bore 12.

At the drive side of the pump housing 1, the coupling end 7.2 of the drive shaft 7 projects out of the pump housing 1. The coupling end 7.2 of the drive shaft 7 has a diameter shoulder 40 in the end region, against which a support ring 34 rests. The support ring 34 is L-shaped and is held in a recess of a support housing 33.

The support housing 33 is penetrated by the drive shaft 7 and projects with the free coupling end 7.2 for connecting a drive from the support housing 33 out. For the removal of the protruding from the support housing 33 coupling end 7.2 of the drive shaft 7, a shaft seal 39 is disposed within the support housing 33 on the circumference of the drive shaft. The support housing 33 is pressure-tightly connected via a seal housing 26 to the pump housing 1. For this purpose, between the pump housing 1 and the seal housing 26, a first housing seal 32.1 is arranged concentrically with the bearing bore 10 and between the seal housing 26 and the support housing 34, a second housing seal 32.2. The seal housing 26 has a recess formed concentrically to the drive shaft 7, which serves for receiving a stuffing box 27 arranged on the circumference of the drive shaft 7. The gland packing 27 is supported on the pump housing 1 facing the end of the Seal housing 26 directly on the housing plate 1.2 from. At the opposite end of the gland packing 27, a clamping means 28 is provided in the seal housing 26.

The tensioning means 28 is formed by a spring, which is held in the seal housing via a clamping bush 29.

Between the stuffing box 27 and the shaft seal 39 an annular space 35 is formed. The annular space 35 is connected via two channels 36. 1 and 36. 2 respectively to an inlet 37 and an outlet 38 in the sealing housing 26. The inlet 37 and the outlet 38 are designed to be closable, so that in the operating state a barrier liquid is introduced into the seal housing 26, through which the annular space 35 is filled. In this case, preferably a solvent-containing fluid is used as barrier liquid in order to dissolve the paint particles possibly leaving through gap leaks within the annular space 35, so that hardening in the gap is prevented. In particular, taking into account an adjustment of the spring tension, the mobility of the gland packing 27 is ensured. In addition, a flushing of the annular space 35 via the channels 36.1 and 36.2 can be carried out in a simple manner during maintenance and replacement of the barrier liquid.

This in Fig. 4 and 5 illustrated embodiment of the gear pump according to the invention is particularly suitable to carry out the metering of paint colors with high operating pressures. In particular, when using such gear pumps in painting robots, a return of the gear pump is set in a color change to initiate a color change. In addition, the forces acting from the outside on the drive shaft 7 can be absorbed by the support bearing of the support ring in the support housing 33, so that the gears in the interior of the pump housing 1 are free of axial forces. This is particularly the signs of wear on the driven gear 4 reduce. The support ring 34 can thus also be replaced by a conventional rolling bearing.

The scavenging system 18 formed within the pump housing is identical to the embodiment according to FIG Fig. 1 and 2 executed, so that at this point no further explanation is done. The non-sealed gaps between the housing plates 1.1 and 1.2, the drive shaft 7 and the gears 4 and 5 can thus advantageously flush through a detergent.

In the Fig. 6 is a further embodiment of a gear pump according to the invention shown schematically in a cross-sectional view. The exemplary embodiment is essentially identical to the exemplary embodiment according to FIG Fig. 3 , so that only the differences will be explained below and otherwise reference is made to the above description.

At the in Fig. 6 illustrated gear pump, the drive shaft 7 is mounted within the formed by the housing plates 1.1, 1.2 and 1.3 pump housing 1 in the bearings 8.1 and 8.2. The bearing 8.1 is formed in the housing plate 1.1, which has a storage bag bore 16 for this purpose. The second bearing 8.2 is formed by the bearing bore 17 of the housing plate 1.2.

The gears 4 and 5 are held between the housing plates 1.1 and 1.2. The driven gear 4 is connected via a stepped bore 12 with the drive shaft 7. For this purpose, the drive shaft 7 has two diameter stages 23.1 and 23.2. In the transition region of the diameter stages 23.1 and 23.2, an axially extending mold groove 25 is provided within the bore 12, in which purely pin 24 of the drive shaft 7 engages. For a rotationally fixed positive connection between the drive shaft 7 and the gear 4 is formed.

In the diameter portion of the diameter stage 23.1 of the drive shaft 7, a circumferential pass bar 42 is arranged. The pass bar 42 is located in the central region of the gear 4 and is fitted without play in the bore 12 of the gear 4. In the areas outside the fitting web 42, a small gap is provided between the diameter section of the diameter step 23. 1 and the bore 12 of the gear 4. Likewise, a clearance fit between the diameter portion of the diameter stage 23.2 and the bore 12 of the gear 4 is also formed, so that the gear around the fitting web 42 can perform a pendulum movement in the axial direction. The pendulum movement of the gear 4 is intercepted on both sides of the fitting web 42 by a respective sealing ring 14.1 and 14.2. The sealing rings 14.1 and 14.2 are arranged for this purpose on the circumference of the drive shaft in the respective sections of the diameter stages 23.1 and 23.2. This allows complete tolerances such as the parallelism of the housing plates 1.1 and 1.2 with respect to the gear end faces of the gear 4 completely compensate. The gear 4 can be particularly wear-resistant between the housing plates 1.1 and 1.2.

The drive shaft penetrates the housing plate 1.2 and a pressure-tight manner connected to the housing plate 1.2 seal housing 26, so that a coupling end 7.2 of the drive shaft 7 is cantilevered held for connecting a drive. In the transition region between the housing plate 1.2 and the seal housing 26, a seal is provided, for example, as a stuffing box 27, which is arranged on the circumference of the drive shaft 7 and between the grooves of the housing plate 1.2 and the density housing 26 is tensioned.

Within the seal housing 26, an additional support bearing of the drive shaft 7 is formed. For this purpose, a rolling bearing 41 is disposed between the seal housing 26 and the drive shaft 7. The rolling bearing 4.1 is supported on a shaft shoulder 40 of the drive shaft. For sealing the bearing area, the rolling bearing 41 is associated with a shaft sealing ring 39, which is arranged downstream of the first sealing means 27 on the circumference of the drive shaft 7 to the drive side.

This in Fig. 6 illustrated embodiment is thus particularly suitable to absorb external forces acting on the drive shaft 7 forces by the rolling bearing 41 immediately outside of the pump housing 1. Thus, the driven gear 4 can be guided within the pump housing 1 free of axial forces. Due to the additional pendulum mobility of the gear 4, a wear-gentle guidance of the gear 4 is possible. In order to realize a sufficient pendulum mobility of the gear on the circumference of the drive shaft 1, the fitting web 42 is preferably arranged in the central region of the gear 4 and executed with a fitting length which is smaller than one quarter of the gear width. The fitting web 42 can alternatively be formed on the circumference of the bore 12 of the gear 4. In the remaining areas between the drive shaft 7 and the gear 4 Passungsspiele are provided in order to obtain sufficient mobility of the gear 4.

All not further described in detail components of the embodiment according to Fig. 6 are essentially identical to the embodiment according to Fig. 3 educated. To avoid repetition, therefore, no further explanation will be given. In principle, however, it should be noted that the bearing pin 21 of the gear 5 may alternatively be supported in the housing plates 1.1 and 1.2 stored. Likewise, the gear pump has a Spülkanalsystem not explained in detail here and shown in order to perform a fast and safe color change when promoting paints can.

The in the FIGS. 1 to 6 illustrated embodiments of the gear pump according to the invention are exemplary in their structure and design of the individual components. In particular, the selected between the drive shaft 7 and the gear 4 examples of the connecting means 9 can be replaced by other constructive solutions. Essential here, however, is; in that the one or more gaps forming between the toothed wheel and the drive shaft are respectively sealed off towards the front sides of the toothed wheel, so that no leakage occurs from the outside can get between the drive shaft and the gear.

LIST OF REFERENCE NUMBERS

1

pump housing

1.1

housing plate

1.2

housing plate

1.3

center plate

1.4

seal

1.5

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, 8.1, 8.2

depository

9

connecting means

10

notch

10.1

latching body

10.2

feather

11

wave recess

12

drilling

13

recess

14.1, 14.2

sealing ring

15.1, 15.2

seal groove

16

Bearing blind hole

17

bearing bore

18

Coils duct system

18.1, 18.2, 18.3

irrigation channel

19

Intake

20

shaft seal

21

pivot

22

Press bore

23.1, 23.2, 23.3

Durchmesserstrufen

24

pen

25

forming groove

26

seal housing

27

gland packing

28

clamping means

29

clamping bush

30

polygonal shape

31.1, 31.2

bearing bush

32.1, 32.2

housing seal

33

support housing

34

support ring

35

annulus

36.1, 36.2

channel

37

inlet

38

outlet

39

Shaft seal

40

shaft shoulder

41

roller bearing

42

Passungssteg

Claims (18)

1. Gear pump with two intermeshing gears (4, 5), which are mounted to rotate within a pump housing (1) through a driveshaft (7) and a journal (21) and form a feed channel system (6) between a pump inlet (2) and a pump outlet (3), and with several gaps formed between the pump housing (1), gears (4, 5), driveshaft (7) and journal (21), in which one of the gaps is formed between the driveshaft (7) and one of the gears (4), and in which a connection device (9) is arranged in the gap for splined connection of the driveshaft (7) to gear (4),
   characterized by the fact that
   the gap between driveshaft (7) and gear (4) is sealed to the front ends of gear (4) by a packing (14.1, 14.2).
2. Gear pump according to Claim 1,
   characterized by the fact that
   the packings are formed by at least two sealing rings (14.1, 14.2) arranged at a spacing from each other on the periphery of driveshaft (7), the spacing between sealing rings (14.1, 14.2) being equal to or less than the width of gear (4).
3. Gear pump according to Claim 2
   characterized by the fact that
   sealing rings (14.1, 142.) are held in radially peripheral sealing grooves (15.1, 15.2) in the periphery of driveshaft (7) and/or in radially peripheral sealing grooves (15.1, 15.2) in the periphery of a hole (12) of gear (4).
4. Gear pump according to one of the Claims 1 to 3,
   characterized by the fact that
   several diameter steps (23.1, 23.2) are formed between the driveshaft (7) and gear (4), in which the connection device (9) between driveshaft (7) and gear (4) is held in one of the diameter steps (23.2).
5. Gear pump according to Claim 4,
   characterized by the fact that
   the sealing rings (14.1, 14.2) are held in the diameter steps (23.1, 23.2) between driveshaft (7) and gear (4), which enclose the diameter step (23.2) for accommodation of the connection device (9).
6. Gear pump according to Claim 4 or 5,
   characterized by the fact that
   the connection device (9) is formed by a pin (24), which is firmly connected to driveshaft (7) and engages in the shaped groove (25) of gear (4).
7. Gear pump according to Claim 6,
   characterized by the fact that
   the shaped groove (25) of gear (4) is introduced axially to a hole offset formed between two diameter steps (23.2, 23.3).
8. Gear pump according to Claim 4 or 5,
   characterized by the fact that
   the connection device (9) is formed by a polygonal shape (30) of driveshaft (7), which cooperates with a polygonal shape (30) of hole (12) of gear (4).
9. Gear pump according to one of the Claims 1 to 5,
   characterized by the fact that
   the connection device (9) is formed by at least one spring-loaded detent (10), which is held on the periphery of driveshaft (7) and engages in a recess (13) of gear hole (12).
10. Gear pump according to one of the Claims 1 to 9,
    characterized by the fact that
    a flushing channel system (18) for flushing the gaps within the pump housing (1) is provided, through which a separate feed (19) is connected to the feed channel system.
11. Gear pump according to Claim 10,
    characterized by the fact that
    the flushing channel system (18) has several flushing channels (18.1, 18.8), through which several bearing positions (8.1, 8.2) of driveshaft (7) can be flushed from the outside in over their length.
12. Gear pump according to one of the Claims 1 to 11,
    characterized by the fact that
    the pump housing (1) is designed in several parts, in which the front ends of gears (4, 5) are held between two housing plates (1.1, 1.2), and in which the driveshaft (7) is held rotatable in the bearing positions (8.1, 8.2), each with a shaft section directly in receiving hole (16, 17) of the housing plates.
13. Gear pump according to one of the Claims 1 to 12,
    characterized by the fact that
    a sealing housing (26) is arranged pressure-tight on pump housing (1), which is penetrated by the driveshaft (7) in a recess made concentric to driveshaft (7), and which encloses packing (27) arranged on the periphery of driveshaft (7).
14. Gear pump according to one of the Claims 1 to 13,
    characterized by the fact that
    a support bearing (34, 33, 26, 41) for radial and axial support of the driveshaft (7) is formed on a coupling section of driveshaft (7) protruding outside pump housing (1), which is formed by a support ring (34) or a roller bearing (41).
15. Gear pump according to Claim 14,
    characterized by the fact that
    a shaft sealing ring (39) is arranged within support housing (33) on the periphery of driveshaft (7), and that the annular space (35) formed between the packing (27) and the shaft sealing ring (39) is filled with a blocking fluid on the periphery of driveshaft (7).
16. Gear pump according to Claim 15,
    characterized by the fact that
    the annular space (35) is connected via separate channels (36.1, 36.2) to an inlet (37) and an outlet (38), and that the inlet (37) and outlet (38) are formed on the sealing housing (26).
17. Gear pump according to one of the Claims 1 to 16,
    characterized by the fact that

    - a peripheral alignment land (42) is formed on the periphery of hole (12) of gear (4) or on the periphery of driveshaft (7), through which the gear (4) is held free of play against driveshaft (7).
18. Gear pump according to Claim 17,
    characterized by the fact that
    the alignment land (42) is arranged in the middle area of gear (4) and has an alignment length less than one-fourth the gear width.

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