U.S. patent application number 12/598322 was filed with the patent office on 2010-08-05 for gear pump.
Invention is credited to Ulrich Helbing, Arkardiusz Tomzik, Dietrich Witzler.
Application Number | 20100196186 12/598322 |
Document ID | / |
Family ID | 39665991 |
Filed Date | 2010-08-05 |
United States Patent
Application |
20100196186 |
Kind Code |
A1 |
Helbing; Ulrich ; et
al. |
August 5, 2010 |
GEAR PUMP
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.
Inventors: |
Helbing; Ulrich; (Burscheid,
DE) ; Tomzik; Arkardiusz; (Bergisch Gladbach, DE)
; Witzler; Dietrich; (Rommerskirchen, DE) |
Correspondence
Address: |
ALSTON & BIRD LLP
BANK OF AMERICA PLAZA, 101 SOUTH TRYON STREET, SUITE 4000
CHARLOTTE
NC
28280-4000
US
|
Family ID: |
39665991 |
Appl. No.: |
12/598322 |
Filed: |
April 2, 2008 |
PCT Filed: |
April 2, 2008 |
PCT NO: |
PCT/EP08/53968 |
371 Date: |
April 12, 2010 |
Current U.S.
Class: |
418/206.6 ;
418/122 |
Current CPC
Class: |
F04C 15/0026 20130101;
F04C 2/18 20130101; F04C 2220/24 20130101; F04C 15/0038
20130101 |
Class at
Publication: |
418/206.6 ;
418/122 |
International
Class: |
F01C 1/18 20060101
F01C001/18; F01C 19/02 20060101 F01C019/02 |
Foreign Application Data
Date |
Code |
Application Number |
May 3, 2007 |
DE |
10 2007 020 703.6 |
Claims
1.-15. (canceled)
16. A gear pump comprising: two meshing gears configured to convey
paints, said gears comprising a driven gear and an idling gear; and
at least one drive shaft mounted to rotate, which is splined to the
driven gear and is held by bearings in a pump housing, in which the
drive shaft can be connected to a drive and in which a seal is
assigned to the drive shaft on the periphery between the driven
gear and one bearing, which includes a pressure ring lying against
one face of driven gear, wherein a second seal with a second
pressure ring is arranged on the opposite face of gear on the
periphery of the drive shaft between a second bearing and the
driven gear and wherein both pressure rings have a sealing shoulder
opposite the driven gear, each of which is forced against the face
of the driven gear by a spring device.
17. The gear pump according to claim 16, wherein the seals each
have a sealing ring and wherein the sealing rings shield the
bearings on both sides of the driven gear relative to the pressure
rings and delimit on the periphery of the drive shaft a rinsing
space formed between the pressure ring and the sealing ring.
18. The gear pump according to claim 17, wherein each of the
rinsing spaces is connected by a rinsing channel in the pump
housing to a rinsing connection.
19. The gear pump according to claim 17, wherein the two rinsing
stations are connected to each other via several rinsing grooves
between the drive shaft and the pressure rings and between the
drive shaft and the driven gear.
20. The gear pump according to claim 16, wherein the bearings are
formed to support the drive shaft by at least two roller bearings
whose roller bodies are held in an annular chamber filled with a
lubricant.
21. The gear pump according to claim 16, wherein the idling gear is
splined to a shaft pin, which is supported on both sides of the
idling gear by several bearings and wherein a seal is arranged on
both sides of the idling gear on the periphery of the shaft pin,
each of which has a pressure ring lying against the face of the
idling gear.
22. The gear pump according to claim 21, wherein the seals each
have a sealing ring and wherein the sealing rings shield the
bearings on both sides of the idling gear relative to pressure
rings and delimit a rinsing space formed on the periphery of the
shaft pin between the pressure ring and sealing ring.
23. The gear pump according to claim 22, wherein each of the
rinsing spaces is connected via a rinsing channel in the pump
housing to a rinsing connection.
24. The gear pump according to claim 22, wherein the two rinsing
spaces are connected to each other via several rinsing grooves
between the shaft pin and the pressure rings and between the shaft
pin and the idling gear.
25. The gear pump according to claim 21, wherein the bearings are
formed to support the shaft pin through at least two roller
bearings whose roller bodies are held in an annular chamber filled
with lubricant.
26. The gear pump according to claim 16, wherein the pressure rings
are formed from a ceramic material and wherein the sealing rings
are each designed as a groove ring.
27. The gear pump according to claim 16, wherein the spring devices
for pressing the pressure rings are each formed from a belleville
spring stack.
28. The gear pump according to claim 16, wherein the faces of gears
are formed from a ceramic material.
29. The gear pump according to claim 16, wherein the drive shaft is
formed from a bearing shaft and a coupling shaft connected by a
releasable rotary connection to bearing shaft, wherein the bearing
shaft is connected to the driven gear within the pump housing and
is supported by the bearings and wherein the coupling shaft is
mounted to rotate outside of the pump housing in a support housing
through a support bearing and can be connected to a drive on the
free end.
30. The gear pump according to claim 29, wherein the support
housing is firmly connected to the pump housing and is penetrated
by the drive shaft in a recess.
Description
[0001] The invention concerns a gear pump for transport of paints
according to the preamble of Claim 1.
[0002] A generic gear pump is known from EP 1 280 996 B1. The known
gear pump has two meshing gears mounted to rotate within a pump
housing. One of the gears is connected to a drive shaft mounted in
a bearing site within the pump housing. The drive shaft penetrates
the pump housing in the bearing site and is connected to a drive
outside the pump housing. For sealing of the outward guided drive
shaft a sealing device is assigned to the gear on the drive shaft,
which seals the bearing device of the drive shaft relative to a
feed space formed on the periphery of the gear. Here the seal has a
ceramic ring that is supported on one face of the gear under a
bias.
[0003] Through this one-sided support of the seal on the face of
the gear the gear is forced against the pump housing with the
opposite face so that non-uniform sealing gaps are produced because
of nonsymmetric loading of the gear. The suspicion that force
balance occurs during operation with the operating force acting on
both sides of the gear because of the larger opposite face of the
gear is also not true, since, according to experience, a pressure
drop occurs over the length of the sealing gap between two bodies.
Nonsymmetric loading of the gear also persists during operation so
that increased friction occurs between the gear and the pump
housing on the face of the gear opposite the seal.
[0004] Another gear pump to convey and meter paints is known from
DE 10 2005 016 670 A1 in which seals are arranged in the pump
housing on both faces of the driven gear in order to separate the
feed area within the pump housing from the bearing area of the
drive shaft. The seal here is formed by a seal and spring element
that loads the seal with a small force in the direction toward the
gear. Symmetric loading of the gear on both sides does occur here,
but with the drawback that the seal is arranged in an outer
peripheral area of the gear so that the seal because of the
relatively large diameter rubs against the faces of the gear with
relatively large contact surface and therefore leads to higher wear
phenomena. In addition, because of the sealing grooves formed in
the pump housing only relatively small spring elements can be
integrated, which according to experience can only generate limited
friction forces for pressing the seal. Only limited sealing of the
gap between the faces of the gear and the pump housing can be
achieved in this respect. Another drawback of the known gear pump
is due to the fact that leaks of the sealing sites directly lead to
a situation in which paint reaches the bearing site of the drive
shaft, which is particularly difficult to remove especially during
rinsing.
[0005] It is now the task of the invention to modify a gear pump of
the generic type so that, on the one hand, high sealing relative to
the bearing sites of the drive shaft against the gear is achieved
and, on the other hand, good rinseability of the pump is
retained.
[0006] Another objective of the invention is to devise a gear pump
of the generic type in which bearing friction of the drive shaft
remains essentially constant during operation.
[0007] This task is solved by a gear pump with the features
according to Claim 1.
[0008] Advantageous modifications of the invention are defined by
the feature combinations of the corresponding dependent claims.
[0009] The invention has the particular advantage that the driven
gear is guided freely in the pump housing and forms a relatively
uniform sealing gap on each face with the pump housing. For this
purpose a second seal with a second sealing ring is arranged on the
opposite face of the gear on the periphery of the drive shaft
between a second bearing and the gear, in which both pressure rings
each have a sealing shoulder on both faces of the gear and are
forced against the faces of the gear by a spring device. The gear
is tightened between the pressure rings and therefore independent
of the position of the drive shaft. Run-up of one of the faces
against one of the housing plates is avoided on this account and
the gear forms an equally large sealing gap relative to each face
with the pump housing. The sealing rings biased on both sides as
well as the position of the gear fixed on this account permit a
high sealing effect so that the paint emerging from the feed space
advances essentially into the lateral sealing gap only up to the
sealing shoulders of the pressure rings. The bearings within the
pump housing remain free of paint so that rinsing of the bearing
sites of the drive shaft is unnecessary. The requirements for
rinseability can therefore be omitted in designing the
bearings.
[0010] In order to prevent even small paint residues from passing
through the sealing site between the pressure rings and the gear
and the pressure rings and the pump housing and reaching the
bearings, the modification of the invention is preferably used in
which the seals each have a sealing ring, which shield the bearings
on both sides of the gear relative to the pressure rings and
delimit a rinsing space formed between the pressure ring and the
sealing ring on the periphery of the drive shaft. The sealing
rings, which are arranged on the periphery of the drive shaft and
have a sealing effect between the pump housing and the drive shaft
form a second seal arranged after the pressure rings in order to
separate the bearing sites from the feed space. Even residues of
paint entering the rinsing space are therefore kept away from the
bearings.
[0011] Since the gear pumps used to convey paints are rinseable to
execute a paint change it is prescribed that each of the rinsing
spaces is connected to a rinsing connection through a rinsing
channel on the pump housing. The paint that has entered the rinsing
space can therefore be flushed out before a paint change by means
of a rinse liquid fed via the rinsing connection.
[0012] In order to be able to flush the joint gap that forms
between the gear and the drive shaft with a rinsing agent it is
proposed according to a modification of the invention to connect
the two rinsing spaces by several rinsing channels between the
drive shaft and the pressure rings as well as the between the drive
shaft and the gears.
[0013] Because of a high sealing effect between the bearing sites
and the feed area of the gear pump all common gears can be used to
support the drive shaft. The bearing devices can therefore be
formed by bearing sleeves for plain bearing of the drive shaft, but
in which outside agents are used in the case of bearing
lubrication. In order to obtain the highest possible lifetimes and
operating times of the gear pump the bearings to support the drive
shaft are preferably formed according to an advantageous
modification of the invention by at least two roller bearings whose
roller bodies are held in an annular chamber filled with lubricant.
Grease fillings are preferably used here as lubricants so that the
drive shaft can be driven with relatively limited bearing
friction.
[0014] During feed of paints, for example, in painting
installations for painting of auto body parts for vehicles it must
be kept in mind in particular that the supplied amount of paint is
adjustable via the speed of the drive shaft and remains constant
during operation during selection of a drive speed. For this
purpose it is essential that tooth engagement of the driven gear
and the idling gear occur with the least possible play in order to
avoid tolerance-related feed fluctuations. To this extent the
modification in which the idling gear is connected to rotate in
unison with a shaft pin, which is supported on both sides of the
gear by several bearings, is particularly advantageous in order to
guarantee constant feed. In this case a seal is provided on the
periphery of the shaft pin on both sides of the gear, each of which
has a pressure ring lying against one of the faces of the gear.
[0015] The bearings of the shaft pin can then also be preferably
shielded by sealing rings relative to the pressure rings so that no
paint residues soil the bearings. Sealing rings form with the
pressure rings on the periphery of the shaft pin on each side of
the gear a rinsing space which is connected through a rinsing
channel and pump housing to a rinsing connection. The leakage
emerging on the idling gear through the gap between the pump
housing and the gear can also be removed by rinsing after entering
the rinsing spaces.
[0016] To rinse the joint gap between the gear and the shaft pin it
is also proposed that the two rinsing spaces be connected to each
other by several rinsing channels between the shaft pin and the
pressure rings and between the shaft pin and the gear.
[0017] The bearings to support the shaft pin are preferably
designed identical to the bearings of the drive shaft. Plain
bearing with bearing sleeves would be possible. The bearings to
support the shaft pin, however, are preferably formed by at least
two roller bearings whose roller bodies are held in an annular
chamber filled with a lubricant.
[0018] In order to minimize wear of the seals relative to the gear,
on the one hand, and to obtain a high sealing effect relative to
the bearings, on the other, according to a modification of the
invention the pressure rings are formed from a ceramic material and
the sealing rings are designed as so-called groove rings.
[0019] For the sealing effect of the sealing sites formed between
the pressure rings and the gears the bias force generated by the
spring device is decisive, with which a sealing shoulder of the
pressure ring is held against the face of the gear. It is essential
here that the generated bias force remains essentially constant
during the operating time of the pump. To this extent the
modification of the invention in which the spring device is formed
by a belleville spring stack has proven itself as a spring device
for pressing the pressure rings. In this case high spring forces
can be generated even in small design spaces on the periphery of
the drive shaft or shaft pin.
[0020] The advantageous modification of the invention in which the
faces of the gears are formed from a ceramic material has the
particular advantage that even with larger bias forces of the
pressure rings increased wear phenomenon cannot occur. In addition,
the friction forces generated between the faces of the gears and
the sealing shoulders of the pressure rings made from ceramic
remain relatively low.
[0021] In order to keep the gap that forms between the gears and
the pump housing within the narrowest possible tolerance with high
sealing effect, the pump housing is preferably designed in several
parts, the faces of the gears being held between two housing
plates. The plate design permits precision machining of the pump
housing so that high plane-parallelism can be set between the gears
and the housing plates.
[0022] In another advantageous modification of the invention it is
proposed to form the drive shaft from a bearing shaft and a
coupling shaft connected to the bearing shaft through a releasable
rotary connection, in which the bearing shaft is connected to the
gear within the pump housing and supported by the bearing. The
coupling shaft, on the other hand, is mounted to rotate outside of
the pump housing in a support housing through a support bearing and
can be connected to the drive on the free end. The external forces
acting on the drive shaft can also be advantageously taken up by
the support bearing.
[0023] The gear pump according to the invention is further
explained below by means of some practical examples with reference
to the accompanying figures.
[0024] In the figures
[0025] FIG. 1 schematically depicts a section view of a first
practical example of the gear pump according to the invention
[0026] FIG. 2 schematically depicts a sectional view of the shaft
pin of the practical example from FIG. 3
[0027] FIG. 3 schematically depicts a sectional view of another
practical example of the gear pump according to the invention
[0028] FIG. 4 schematically depicts a sectional view of the drive
shaft of the practical example from FIG. 1.
[0029] A first practical example of the gear pump according to the
invention is shown in a schematic sectional view in FIG. 1 and FIG.
2. FIG. 2 shows only an enlarged cutout from FIG. 1 so that the
subsequent description applies to both figures.
[0030] The gear pump has a pump housing 1, designed in several
parts and consists of housing plates 1.1 and 1.2 as well as the
center plate 1.3 held between housing plates 1.1 and 1.2. The
housing seals 1.4 and 1.5 are arranged between the faces of the
housing plates 1.1 and 1.2, through which the gap between the
center plate 1.3 and the housing plates 1.1 and 1.2 is sealed
outward. The center plate 1.3 has recesses for two meshing gears 4
and 5. In the overlapping area of gears 4 and 5 a feed channel
system 6 is formed in the housing parts, which is connected to a
pump inlet 2 formed in housing plate 1.2 and to a pump outlet 3
formed in housing plate 1.1. The feed channel system 6 is
preferably formed by holes and recesses in housing plates 1.1 and
1.2 as well as center plate 1.3.
[0031] The gear 4 is splined to a drive shaft 7. For this purpose
the gear 4 is forced through a center hole 28 of the drive shaft 7.
A connection device 29 (shown with a dashed line here) is provided
between the periphery of drive shaft 7 and the hole 28 of gear 4,
through which a shape-mated and splined connection is formed
between the drive shaft 7 and gear 4. The drive shaft 7 has a
bearing end 7.1 within pump housing 1 and a coupling end 7.2
outside of pump housing 1. For this purpose a through mounting hole
18 is provided in housing plate 1.1 and housing plate 1.2, which is
essentially penetrated coaxially by drive shaft 7. A seal 9.1 and
9.2 and a bearing 8.1 and 8.2 are arranged in the housing plate 1.1
and the housing plate 1.2 between the periphery of drive shaft 7
and the mounting hole 18 of housing plates 1.1 and 1.2. Each of the
seals 9.1 and 9.2 has a pressure ring 10.1 and 10.2. The pressure
rings 10.1 and 10.2 are axially movable in the periphery of the
drive shaft 7 and each supported with a sealing shoulder 16.1 and
16.2 on the faces of gear 4. The pressure rings 10.1 and 10.2 as
well as the faces of gear 4 are preferably formed from a ceramic
material for this purpose. The gear 4 and the pressure rings 10.1
and 10.2 can also be completely formed from a ceramic material.
[0032] A spring device 11.1 and 11.2 is arranged on the side of
each pressure ring 10.1 and 10.2 opposite sealing shoulders 16.1
and 16.2. The spring device 11.1, which is formed in this practical
example as a belleville spring stack, is tightened between a
retaining ring 17 fastened in housing plate 1.1 and the pressure
ring 10.1. The spring device 11.2 acts on the opposite side of gear
4, also being designed as a belleville spring stack, between an
additional retaining ring 17 fastened in housing plate 1.2 and
pressure ring 10.2.
[0033] The seals 9.1 and 9.2 also each have a sealing ring 12.1 and
12.2 on the side facing the bearings 8.1 and 8.2, which is held
between the periphery of drive shaft 7 and the mounting hole 18 in
the housing plates 1.1 and 1.2. The seals 12.1 and 12.2 in this
practical example are formed by groove rings which generate
radially acting pressure forces between the drive shaft 7 and the
mounting holes 18.
[0034] The sealing rings 12.1 and 12.2 are held with a spacing
relative to pressure rings 10.1 and 10.2 on the periphery of the
drive shaft 7 so that a rinsing space 13.1 and 13.2 is formed in
the intermediate space between the drive shaft 7 and the mounting
hole 18. Rinsing space 13.1 is coupled via a rinsing channel 14.1
in housing plate 1.1 to a rinsing connection 15.1. The rinsing
space 13.2 formed on the opposite side of gear 4 in seal 9.2 is
connected via rinsing channel 14.2 in housing plate 1.2 to a
rinsing connection 15.2. During operation the rinsing connections
15.1 and 15.2 are connected to a rinsing system.
[0035] The rinsing spaces 13.1 and 13.2 are connected by several
rinsing grooves 36.1 and 36.2. The rinsing grooves 36.1 here each
denote the rinsing groove that extends between the pressure ring
10.1 and the drive shaft 7 and the pressure ring 10.2 and the drive
shaft 7. The rinsing groove 36.1 can be formed here by a groove on
the periphery of the drive shaft or by a groove on the inside
diameter of the pressure ring. The rinsing groove 36.2 denotes a
connection between the faces of gear 4, in which this can be formed
by a groove in the hole 28 of gear 4 or by a groove on the
periphery of drive shaft 7.
[0036] To support the drive device the bearings 8.1 and 8.2 are
each arranged in the outer areas of housing plates 1.1 and 1.2. The
bearings 8.1 and 8.2 are formed for this purpose by roller bearings
32 having a number of roller bodies 30, which are held in closed
annular chamber 31 between an inner and outer race. The roller
bearings 32 are held in the axial direction by a retaining ring 17
fastened in the housing plates 1.1 and 1.2. A grease filling is
preferably contained as lubricant in the closed annular chamber 31,
which preferably guarantees lubrication of roller bodies during the
operating time of the gear pump.
[0037] The mounting hole 18 in housing 1.1 is closed outward by
cover 27. On the opposite drive side of pump housing 1 the coupling
end 7.2 of drive shaft 7 protrudes from the mounting hole 18 of
housing plate 1.2. The coupling end 7.2 of drive shaft 7 has a
diameter shoulder 33 in the end area on which a support ring 20
lies. The support ring 20 is designed L-shaped and held in a recess
of a support housing 19.
[0038] The support housing 19 has a recess 21, penetrated by the
drive shaft 7 completely so that the free coupling end 7.2 of drive
shaft 7 protrudes from the support housing 19 for connection of a
drive. The support housing 19 is firmly connected to pump housing
1.
[0039] The gear 4 driven by drive shaft 7 engages with gear 5,
which rotates freely between housing plates 1.1 and 1.2 and is held
in center plate 13. The gear 5 is held with its hole on a bearing
pin 34. The bearing pin 34 in this example is not mounted in the
housing plates 1.1 and 1.2 so that the gear 5 is only guided
through the housing plates 1.1 and 1.2 and through center plate 1.3
and is driven by gear 4.
[0040] In the gear pump depicted in FIG. 1 the gear 4 is driven by
drive shaft 7 during feed of paint. A paint fed via pump inlet 2 is
conveyed by the meshing gears 4 and 5 into the feed channel system
6 under pressure to the pump outlet 3. The leakage emerging from
the feed channel 6 through the gap between the faces of gears 4 and
5 and housing 1.1 and 1.2 is held by pressure rings 10.1 and 10.2
against the faces of gear 4 under a bias so that the joint gap
between gear 4 and the drive shaft 7 remains essentially free of
leaks.
[0041] The leaks that might emerge through the gap between pressure
ring 10.1 and 10.2 and housing plates 1.1 and 1.2 are taken up by
the tolerances 13.1 and 13.2. Hermetic sealing relative to bearings
8.1 and 8.2 occurs through the sealing rings 12.1 and 12.2 assigned
to the pressure rings 10.1 and 10.2 so that no leaks can enter the
bearings 8.1 and 8.2.
[0042] In order to eliminate the leaks with paint residues from the
rinsing spaces 13.1 and 13.2 and the gaps between the gear 4 and
drive shaft 7 during a paint change, a rinse liquid is introduced
to the pump housing through rinse connections 15.1 and 15.2 and
flushes the intermediate spaces between the drive shaft 7, the
housing plates 1.1 and 1.2 and gear 4. The feed channel system 6
within the pump housing is then also flushed by means of a rinse
liquid via pump inlet 2 and pump outlet 3 so that the gaps between
the gears 4 and housing plates 1.1 and 1.2 and center plate 1.3 can
also be flushed.
[0043] Another practical example of the gear pump according to the
invention is schematically depicted in FIGS. 3 and 4 in a
cross-sectional view. The practical example is essentially
identical in design of the gear pair of gears 4 and 5 and pump
housing 1 to the practical example according to FIG. 1 so that
reference is made to the aforementioned description and only the
differences are explained. The components with the same functions
received identical reference numbers for this purpose. In addition,
FIG. 4 shows only an enlarged view of a cutout of FIG. 3 so that
the following description applies for both figures.
[0044] The drive shaft 7 splined with gear 4 is formed in this
practical example by a bearing shaft 25 and a coupling shaft 26,
which are connected to each other by a rotary connection 24. The
bearing shaft 25 is mounted to rotate via bearings 8.1 and 8.2 in
the mounting holes 18 of housing plates 1.1 and 1.2. The seals 9.1
and 9.2 assigned to the bearings 8.1 and 8.2 are formed on the
periphery of bearing shaft 25 and bearings 8.1 and 8.2 identical to
the previous practical example so that reference can be made to the
preceding description.
[0045] The bearing shaft 25 essentially extends over the width of
housing plates 1.1 and 1.2, the bearing shaft 25 being coupled to
the coupling shaft 26 on the drive side. For this purpose moldings
are made on the ends of bearing shaft 25 and coupling shaft 26,
which represent the rotary connection 24.
[0046] The coupling shaft 26 is mounted to rotate via a support
bearing 22 in a support housing 19. The coupling shaft 26 is then
held both in the actual direction and in the radial direction by
the support bearing 22 in support housing 19. The coupling shaft 26
has a free end protruding from support housing 19, which can be
connected to a drive (not shown here).
[0047] The idling gear 5 is connected on the periphery of a shaft
pin 23 to rotate in unison with it. The shaft pin 23 for this
purpose penetrates the hole in gear 5 and is mounted on both sides
of the gear 5 in mounting holes 35 of housing plate 1.1 and housing
plate 1.2. On the periphery of shaft pin 23 on both sides of gear 5
the bearings 8.3 and 8.4 are provided. The bearings 8.3 and 8.4 are
formed by roller bearings 32 which are identical in design to the
roller bearing 32 to support the drive shaft 7. To this extent each
of the roller bearings 32 has several roller bodies 30, which are
held in a closed annular chamber 31 with a grease filling.
[0048] For sealing of bearing 8.3 and 8.4 seals 9.3 and 9.4 are
provided on the periphery of shaft pin 23 between gear 5 and
bearings 8.3 and 8.4. The seals 9.3 and 9.4 are designed identical,
each of the seals 9.3 and 9.4 having a pressure ring 10.3 and 10.4.
The pressure rings 10.3 and 10.4 are held via spring devices 11.3
and 11.4 against the ends of gear 5 under bias. For this purpose
each pressure ring 10.3 and 10.4 has a sealing shoulder 16.3 and
16.4, which is supported on the faces of gear 5.
[0049] The spring devices 11.3 and 11.4 in this practical example
are formed by belleville spring stacks that are fastened in the
mounting hole 35 by retaining ring 17.
[0050] With a spacing to pressure rings 10.1 and 10.2 the seal
rings 12.3 and 12.4 are assigned to the bearings 8.3 and 8.4 and
the periphery of the shaft pin 23, the sealing rings 12.3 and 12.4
being designed as groove rings that seal the annular space between
the shaft pin 23 and the mounting hole 35 outward. A rinsing space
13.3 and 13.4 is formed on the periphery of shaft pin 23 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. The rinsing spaces
13.3 and 13.4 are each connected through a rinsing channel 14.3 in
housing plate 1.1 and a rinsing channel 14.4 in housing plate 1.2
to a rinsing connection 15.3 on housing plate 1.1 and a rinsing
connection 15.4 on housing plate 1.2.
[0051] The mounting hole 35 is closed outward in housing plate 1.1
and housing plate 1.2 by a cover 27.
[0052] In the practical example depicted in FIGS. 3 and 4 during
operation sealing of the bearing sites of shaft pin 23 and pump
housing 1 occurs in similar fashion to the drive shaft according to
the practical example of FIG. 1. The idling gear 5 is therefore
also tightened between two pressure rings 10.3 and 10.4, the
pressure rings 10.3 and 10.4 also preferably being formed from a
ceramic material and at least the front area of the gear 5, against
which the sealing shoulders 16.3 and 16.4 lie with bias, also being
formed from a ceramic material. In the practical example depicted
in FIG. 3 the gears 4 and 5 are preferably made from a solid
ceramic or side flanks coated with ceramic. Because of this ceramic
material pairs can be used in order to form the sealing sites
produced on the faces of gears 4 and 5 to the sealing rings 10.1 to
10.4.
[0053] Practical examples depicted in FIGS. 1 to 4 are examples of
design and arrangement of bearings to support the drive shaft and
the shaft pin. In principle, the roller bearings can be replaced as
an alternative by plain bearings or other common bearings. The
depicted rinsing channels and rinsing connections are also
considered optional. Thus, rinsing in the gear pump can also be
carried out via the existing pump connections and the existing gaps
between shafts, gears and housing parts. In this case no additional
rinsing channels would be necessary.
LIST OF REFERENCE NUMBERS
[0054] 1 Pump housing
[0055] 1.1 Housing plate
[0056] 1.2 Housing plate
[0057] 1.3 Center plate
[0058] 1.4 Housing seal
[0059] 1.5 Housing seal
[0060] 2 Pump inlet
[0061] 3 Pump outlet
[0062] 4 Gear (driven)
[0063] 5 Gear (idler)
[0064] 6 Feed channel system
[0065] 7 Drive shaft
[0066] 7.1 Bearing end
[0067] 7.2 Coupling end
[0068] 8.1, 8.2, 8.3, 8.4 Bearing
[0069] 9.1, 9.2, 9.3, 9.4 Seal
[0070] 10.1, 10.2, 10.3, 10.4 Pressure ring
[0071] 11.1, 11.2, 11.3, 11.4 Spring device
[0072] 12.1, 12.2, 12.3, 12.4 Sealing ring
[0073] 13.1, 13.2, 13.3, 13.4 Rinsing space
[0074] 14.1, 14.2, 14.4, 14.5 Rinsing channel
[0075] 15.1, 15.2, 15.3, 15.4 Rinsing connection
[0076] 16.1, 16.2, 16.3, 16.4 Sealing shoulder
[0077] 18 Mounting hole
[0078] 19 Support housing
[0079] 20 Support ring
[0080] 21 Recess
[0081] 22 Support bearing
[0082] 23 Shaft pin
[0083] 24 Pressure connection
[0084] 25 Bearing shaft
[0085] 26 Coupling shaft
[0086] 27 Cover
[0087] 28 Hole
[0088] 29 Connection device
[0089] 30 Roller body
[0090] 31 Annular chamber
[0091] 32 Roller bearing
[0092] 33 Diameter shoulder
[0093] 34 Bearing pin
[0094] 35 Mounting hole
[0095] 36.1, 36.2 Rinsing groove
* * * * *