U.S. patent application number 13/994754 was filed with the patent office on 2014-01-30 for axial washer for a gear-type pump comprising an axial washer of this type.
This patent application is currently assigned to Robert BoschGmbH. The applicant listed for this patent is Klaus Heyer, Harald Speer. Invention is credited to Klaus Heyer, Harald Speer.
Application Number | 20140030129 13/994754 |
Document ID | / |
Family ID | 45047830 |
Filed Date | 2014-01-30 |
United States Patent
Application |
20140030129 |
Kind Code |
A1 |
Heyer; Klaus ; et
al. |
January 30, 2014 |
Axial washer for a gear-type pump comprising an axial washer of
this type
Abstract
An axial washer of a gear-type pump, in particular an internal
gear pump, includes a seal which surrounds a pressure area of the
axial washer. The seal is applied to the axial washer as a
free-flowing bonding mass that bonds with the axial washer.
Inventors: |
Heyer; Klaus; (Freiberg,
DE) ; Speer; Harald; (Freiberg, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Heyer; Klaus
Speer; Harald |
Freiberg
Freiberg |
|
DE
DE |
|
|
Assignee: |
Robert BoschGmbH
Stuttgart
DE
|
Family ID: |
45047830 |
Appl. No.: |
13/994754 |
Filed: |
November 30, 2011 |
PCT Filed: |
November 30, 2011 |
PCT NO: |
PCT/EP2011/071358 |
371 Date: |
October 1, 2013 |
Current U.S.
Class: |
418/144 ;
277/500 |
Current CPC
Class: |
F04C 2/086 20130101;
F04C 15/0019 20130101; F04C 2/102 20130101; F01C 21/108 20130101;
F01C 21/102 20130101; F04C 15/0015 20130101; F04C 27/006 20130101;
F04C 15/0026 20130101; F01C 19/005 20130101; F04C 2230/602
20130101 |
Class at
Publication: |
418/144 ;
277/500 |
International
Class: |
F04C 27/00 20060101
F04C027/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 17, 2010 |
DE |
10 2010 063 313.5 |
Claims
1. An axial washer for a gear-type pump, comprising: an axial
washer body having an outer side; and a seal surrounding a pressure
area on the outer side, the seal is being applied to the axial
washer body as a free-flowing and setting compound which, after
setting, forms the seal and is joined materially to the axial
washer body.
2. The axial washer as claimed in claim 1, wherein the axial washer
body has the pressure area.
3. The axial washer as claimed in claim 1, wherein the seal is
applied in a fillet or a groove which surrounds the pressure
area.
4. A gear-type pump, comprising: two meshing gearwheels; an axially
movable, rotationally fixed axial washer configured to laterally
seal a discharge region of a pump space between the gearwheels; a
pressure area on an outer side of the gearwheels, said outer side
facing away from the gearwheels, the pressure area communicating
with the discharge region such that, when subjected to pressure
from the outside, the axial washer is pressed against one side of
the gearwheels of the gear-type pump; and a seal surrounding the
pressure area, the seal is being applied as a free-flowing and
setting compound to the axial washer or to an inner wall of a pump
casing of the gear-type pump facing the axial washer, wherein,
after setting, the free-flowing compound forms the seal and is
joined materially to the axial washer or to the inner wall of the
pump casing.
5. The gear-type pump as claimed in claim 4, wherein the gear-type
pump is an internal gear pump.
Description
[0001] The invention relates to an axial washer for a gear-type
pump and to a gear-type pump comprising at least one axial washer
of this type in accordance with the features of the preambles of
claim 1 or 4.
PRIOR ART
[0002] Axial washers of this kind for axial sealing and for gap
compensation on both sides of the gearwheels of gear-type pumps are
known. By way of example, attention is drawn to patent DE 196 13
833 B4, which has an internal gear pump with an axial washer on
each side of the gearwheels thereof. The axial washer is held in
such a way that it can move axially and is fixed in terms of
relative rotation. On the outer side thereof, i.e. a side facing
away from the gearwheels of the gear-type pump, the axial washer is
subjected to pressure and is pressed by means of the inner side
thereof, the side facing the gearwheels, against the gearwheels in
order to seal off a discharge region of a pump space axially. The
pump space is a circumferential segment between the two gearwheels
in which the gearwheels do not mesh with one another and in which
the gearwheels pump liquid in the circumferential direction from an
intake side to a delivery side of the gear-type pump during the
operation of the gear-type pump, i.e. when the gearwheels thereof
are being driven in rotation. The discharge region is a region of
the pump space in which a higher pressure prevails than on the
intake side or in which the pressure rises to the pressure on the
delivery side during the operation of the gear-type pump, owing to
the pumping action thereof.
[0003] For the application of pressure, the known internal gear
pump has a pressure area for each of the two axial washers thereof.
The pressure area is a flat, crescent-shaped depression which
extends across the discharge region of the pump space and
communicates with the discharge region of the gear-type pump. The
pressure area does not have to have exactly the shape and size of
the discharge region of the pump space: normally the pressure area
has a larger area than the discharge region of the pump space, with
the result that the application of pressure from the outside
results in a force which presses the axial washer inward against
the sides of the gearwheels of the gear-type pump. The pressure
area is sealed off by a seal which surrounds the pressure area. The
seal rests in a groove which extends along an edge of the pressure
area.
[0004] When a pressure is applied from the outside, in other words
a pressure outside the pressure area acting on the seal of the
pressure area is greater than that in the pressure area, there is
the risk that the seal will be forced into the pressure area
because the groove in which the seal rests is lower on the side of
the pressure area by a depth of the pressure area than on the outer
side, this having the effect that the seal is not as well supported
on the side of the pressure area as toward the outside.
DISCLOSURE OF THE INVENTION
[0005] On its outer side, the axial washer according to the
invention, having the features of claim 1, has a seal surrounding a
pressure area. According to the invention, the seal is applied to
the axial washer as a free-flowing and setting compound. For
example, the compound is pasty for application and is applied to
the axial washer by means of a nozzle which imparts the
cross-sectional shape of the seal to the compound.
[0006] Using a nozzle outlet, the pressure area on the axial washer
is circled, with the result that the compound, which is applied in
the form of a strand or a bead, for example, and forms the seal
after setting, surrounds the pressure area. As it emerges from the
nozzle, the compound is viscous enough to retain its shape, i.e.
both its path around the pressure area and its cross-sectional
shape. After setting, the compound applied to the axial washer
forms the seal, which surrounds the pressure area of the axial
washer. As a result of the setting process, the compound forming
the seal, and hence the seal, is joined materially, that is to say
as though adhesively bonded, to the axial washer. The compound
preferably sets so as to be rubber-elastic, thus forming a flexible
seal.
[0007] "Setting" is intended to mean solidification of the
free-flowing, e.g. pasty, compound to form the seal, irrespective
of the solidification mechanism. As stated, the seal is preferably
(rubber-)elastic after setting.
[0008] The invention has the advantage of good stability of the
seal, especially also when subjected to pressure from the outside.
Another advantage is the suitability of the seal according to the
invention for automatic production and application to the axial
washer, with the seal being applied, as described, to the axial
washer as a pasty sealing compound by means of a nozzle, wherein
the nozzle is guided over the axial washer, along the edge of the
pressure area, by a robot or some other machine or, conversely, the
axial washer is guided across the nozzle outlet. Mounting of the
seal, i.e. insertion of a sealing ring into a groove at the edge of
the pressure area, is eliminated. The risk that the seal will not
rest in the groove in the manner envisaged during the assembly of
the gear-type pump is likewise eliminated. It is also conceivable
to apply the seal to the axial washer by means of an injection
mold. The injection mold has the shape of the seal as a cavity and
is clamped to the axial washer in order to injection-mold the seal,
i.e. to apply the setting compound that forms the seal to the axial
washer, with the result that the axial washer closes (covers) the
cavity of the injection mold, and the setting compound can be
injected into the cavity.
[0009] It is possible to provide the pressure area in the outer
side of the axial washer and/or in an inner wall of a pump casing
of the gear-type pump, between which and the gearwheels of the
gear-type pump the axial washer is arranged. Claim 2 provides the
pressure area on the outer side of the axial washer.
[0010] For good stability of the seal, claim 3 envisages that the
seal is applied in a fillet or a groove which surrounds the
pressure area. The fillet or groove supports the seal against the
application of pressure parallel to the outer side of the axial
washer, although a fillet supports the seal in only one
direction.
[0011] Claim 4 relates to a gear-type pump having an axial washer
of the kind explained above. The gear-type pump preferably has
axial washers on both sides of its gearwheels. The pressure area
can be provided on the outer side of the axial washer and/or on an
inner wall of the pump casing between which and the gearwheels of
the gear-type pump the axial washer is arranged. It is likewise
possible for the free-flowing and setting compound which forms the
seal after setting to be applied to the outer side of the axial
washer and/or to the inner wall of the pump casing, there also
being the possibility of applying the seal to the axial washer and
providing the pressure area on the inner wall of the gear-type pump
or vice versa.
[0012] claim 5 envisages that the gear-type pump is an internal
gear pump.
[0013] In particular, the gear-type pump according to the invention
is provided as a hydraulic pump for delivering brake fluid in a
hydraulic, slip-controlled and/or independently powered vehicle
brake system. Although not necessarily applicable, such pumps are
often referred to as return pumps.
BRIEF DESCRIPTION OF THE DRAWING
[0014] The invention is explained in greater detail below by means
of an illustrative embodiment shown in the drawing, in which:
[0015] FIG. 1 shows a side view of a gear-type pump according to
the invention without the pump casing;
[0016] FIG. 2 shows an axial section along the line II-II in FIG.
1; and
[0017] FIG. 3 shows a view of an axial washer according to the
invention for the gear-type pump in FIGS. 1 and 2.
EMBODIMENT OF THE INVENTION
[0018] The gear-type pump 1 according to the invention, which is
shown in FIGS. 1 and 2, is an internal gear pump and is provided
for use as a hydraulic pump for producing a hydraulic brake
pressure in a hydraulic slip-controlled and/or independently
powered vehicle brake system (not shown). Although not necessarily
applicable, such hydraulic pumps for vehicle brake systems are also
referred to as return pumps. The gear-type pump 1 has two
intermeshing gearwheels 2, 3, namely an externally toothed
gearwheel, referred to here as pinion 2, and an internally toothed
annulus 3. The pinion 2 is fixed for conjoint rotation on a pump
shaft 4; it can be driven in rotation by the rotary drive of the
pump shaft 4 and, for its part, drives the annulus 3 in rotation,
said annulus being provided with sliding support for rotation in a
bearing ring 5.
[0019] The gearwheels 2, 3 delimit a crescent-shaped pump space 6
between them, in which a crescent-shaped divider 7 is arranged to
divide the pump space 6 into an intake region 8 and a discharge
region 9. A pin 10, which passes transversely through the pump
space 6, holds the divider 7, and the divider 7 is pivotable on the
pin 10. Tooth tips of teeth of the gearwheels 2, 3 rest against an
outer and an inner side of the divider 7 and slide along the outer
and the inner side of the divider 7 when the gearwheels 2 and 3 are
driven in rotation. During operation of the gear-type pump 1, i.e.
when the gearwheels 2, 3 are driven in rotation, the gearwheels 2,
3 pump brake fluid or, more generally, fluid which is enclosed in
interspaces between the teeth thereof from the intake region 8 to
the discharge region 9, i.e. from an inlet to an outlet of the
gear-type pump 1. An inlet bore 11 opens into the intake region 8,
and a pump outlet is formed by a slot 12 in an axial washer 13,
which will be explained below.
[0020] For axial sealing of the pump space 6, the gear-type pump 1,
which is designed as an internal gear pump, has an axial washer 13
on each of the two sides of the gearwheels 2, 3. Where the edges
17, 18 of the axial washers 13 are concealed by the gearwheels 2,
3, the edges 17, 18 are indicated by dashed lines in FIG. 1. FIG. 3
shows an outer side of one of the two axial washers 13. The axial
washers 13 are situated in an interspace between the gearwheels 2,
3 and the inner walls 14, 15 of a pump casing 16. The axial washers
13 cover at least the discharge region 9 of the pump space 6; in
the illustrative embodiment, the axial washers 13 have the shape of
circular segments which occupy more than the area of the semicircle
and have a recess 19 in the form of an oblique step at a transition
from a circular edge 17 to a straight edge 18 extending in the
direction of a chord. The axial washers 13 have a hole 20 for the
pump shaft 4 and a hole 21 for the pin 10 which holds the
crescent-shaped divider 7. The axial washers 13 can move in the
axial direction and are held in a manner fixed against relative
rotation by the pump shaft 4 and the pin 10. By means of their
inner sides, which face the gearwheels 2, 3, the axial washers 13
rest against the sides of the gearwheels 2, 3 and of the
crescent-shaped divider 7 and seal the pump space 6 off at the
sides.
[0021] On the outer sides, which face away from the gearwheels 2,
3, the axial washers 13 each have a pressure area 22. This is a
flat, crescent-shaped depression in the outer sides of the axial
washers 13 which extends from a central region of the divider 7
across the discharge region of the pump space 6. On the outside,
the pressure area 22 reaches almost as far as the circular edge 17
of the axial washer 13 and, on the inside, almost as far as the
hole 20 for the pump shaft 4. The pressure area 22 is surrounded by
a groove in which there is a seal 23. The seal 23 is applied as a
free-flowing pasty compound into the groove in the axial washer 13
surrounding the pressure area 22, being shaped in the process,
before the gear-type pump 1 is assembled. The compound is applied
by means of a nozzle (not shown), the nozzle outlet of which is
moved along the groove to apply the compound. The nozzle has a
shaping function, imparting its cross-sectional shape to the
compound insofar as the latter projects from the groove. During
application into the groove in the axial washer 13 surrounding the
pressure area 22, the compound is viscous enough to retain the
shape and cross section imparted to it by the nozzle. In the
illustrative embodiment, the compound projects in the form of a
bead with a semicircular cross section from the groove, beyond the
outer side of the axial washer 13. The groove surrounding the
pressure area 22 in the outer side of the axial washer 13 supports
the free-flowing compound and simplifies the production of the seal
by reducing the risk that the compound will flow away. The setting
process joins the seal 23 materially to the axial washer 13. After
setting and the assembly of the gear-type pump 1, the seal 23,
which, as already stated, projects in the form of a bead somewhat
above the outer side of the axial washer 13, rests against the
inner wall 14, 15 of the pump casing 16 and seals off the pressure
area 22 at the inner wall 14, 15. One inner wall 14 is formed by a
bottom of a stepped recess in the pump casing 16, into which the
gear-type pump 1 is installed. The other inner wall 15 is formed by
an inner side of a casing cover 24 which closes the pump casing
16.
[0022] Within the pressure area 22, the axial washer 13 has the
arc-shaped slot 12 already mentioned, which passes through the
axial washer 13. The slot 12 is situated in the discharge region 9
of the pump space 6, and therefore the pressure area 22
communicates with the discharge region 9 of the gear-type pump 1,
which is designed as an internal gear pump. The pressure areas 22
of the axial washers 13 are thus subjected to the pressure which
prevails in the discharge region 9 of the gear-type pump 1, i.e. to
the pressure of the pump outlet. This pressure acts on the outer
sides of the axial washers 13 and presses the inner sides thereof
into sealing contact with the gearwheels 2, 3 and the divider 7 of
the gear-type pump 1, thereby ensuring the lateral sealing of the
pump space 6 in the discharge region 9. The discharge region 9
communicates via the slot 12 in one of the two axial washers 13
with an outlet bore 25 in the pump casing 16.
[0023] By means of the shaping application of the seal 23 as an
initially pasty compound, which sets in the groove in the axial
washer 13 surrounding the pressure area 22 to form the flexible
seal 23, the seal 23 is joined materially to the axial washer 13.
The seal 23 is provided with additional stability by being applied
into the groove surrounding the pressure area 22.
[0024] In the illustrative embodiment, the pump casing 16 is part
of a hydraulic block of a slip control system (not otherwise shown)
of a hydraulic vehicle brake system. Apart from the gear-type pump
1, which forms a hydraulic pump of the slip control system,
additional hydraulic components, such as solenoid valves, are
inserted into the hydraulic block forming the pump casing 16 and
hydraulically interconnected. Hydraulic blocks of this kind are
known to a person skilled in the art, and will not be explained
specifically here. To fill the vehicle brake system, said system is
initially evacuated in order to avoid air inclusions. Brake fluid
is then introduced. During this process, the seal 23 of the
pressure area 22 may be subjected to pressure from outside, i.e.
the pressure on the outside may be higher than that in the pressure
area 22. Because the seal 23 is applied with a shaping action and,
as a result, is joined materially to the axial washer 13, it
withstands such an application of pressure from the outside. In
addition, stability is imparted to the seal 23 by the groove
surrounding the pressure area 22, in which the seal 23 is
situated.
[0025] Instead of being provided in the outer side of the axial
washers 13, the groove with the seal 23 and/or the pressure area 22
can be provided in the inner walls 14, 15 of the pump casing 16,
and the seal 23 can also be provided in the outer side of the axial
washer 13 and the pressure area 22 in the inner wall 14, 15 of the
pump casing 16 or vice versa. It is also possible to provide the
pressure area 22 and/or the seal 23 both on the outer side of the
axial washers 13 and on the inner walls 14, 15 of the pump casing
16 (not shown).
[0026] The pump shaft 4 is provided with sliding support in the
pump casing 16 and in the housing cover 24 by means of two bearing
bushes 26 on both sides of the gearwheels 2, 3, and is sealed off
in the housing cover 24 by means of a seal 27.
* * * * *