U.S. patent application number 13/256072 was filed with the patent office on 2012-06-21 for hydraulic toothed wheel machine.
This patent application is currently assigned to Robert Bosch GmbH. Invention is credited to Guido Bredenfeld, Stefan Cerny, Klaus Griese, Marc Laetzel, Dietmar Schwuchow, Sebastian Tetzlaff, Michael Wilhelm.
Application Number | 20120156080 13/256072 |
Document ID | / |
Family ID | 42557931 |
Filed Date | 2012-06-21 |
United States Patent
Application |
20120156080 |
Kind Code |
A1 |
Laetzel; Marc ; et
al. |
June 21, 2012 |
Hydraulic Toothed Wheel Machine
Abstract
A toothed wheel machine including a housing for receiving two
meshing toothed wheels. The toothed wheels are axially mounted in a
sliding manner by axial surfaces between bearing bodies received in
the housing, and radially by a bearing shaft received in the
bearing bodies. Hydraulic mechanical forces are generated during
the operation of the toothed wheel machine, an axial force
component of the forces acting on each toothed wheel in the same
axial direction. In order to counteract said axial force component,
a pressure field is provided between at least one axial surface of
one of the toothed wheels in the direction of the action of the
axial force component, and the bearing body adjacent to the at
least one axial surface.
Inventors: |
Laetzel; Marc; (Stuttgart,
DE) ; Wilhelm; Michael; (Vaihingen/Enz, DE) ;
Schwuchow; Dietmar; (Stuttgart, DE) ; Bredenfeld;
Guido; (Marbach, DE) ; Cerny; Stefan;
(Ludwigsburg, DE) ; Tetzlaff; Sebastian;
(Reinsdorf, DE) ; Griese; Klaus; (Kupferzell,
DE) |
Assignee: |
Robert Bosch GmbH
Stuttgart
DE
|
Family ID: |
42557931 |
Appl. No.: |
13/256072 |
Filed: |
February 25, 2010 |
PCT Filed: |
February 25, 2010 |
PCT NO: |
PCT/EP2010/001164 |
371 Date: |
March 5, 2012 |
Current U.S.
Class: |
418/206.5 ;
418/206.7 |
Current CPC
Class: |
F04C 15/0042 20130101;
F04C 2/16 20130101; F04C 2240/54 20130101; F04C 15/0088 20130101;
F04C 15/0026 20130101 |
Class at
Publication: |
418/206.5 ;
418/206.7 |
International
Class: |
F01C 1/18 20060101
F01C001/18; F04C 2/18 20060101 F04C002/18 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 12, 2009 |
DE |
10 2009 012 916.2 |
Claims
1. A toothed wheel machine having a housing for accommodating two
intermeshing toothed wheels, which are supported in a sliding
manner axially by axial surfaces between bearing bodies
accommodated in the housing and radially by respective bearing
shafts accommodated in the bearing bodies, in which an axial force
component of a force resulting from hydraulic and mechanical forces
arising during operation of the toothed wheel machine acts on each
toothed wheel in the same axial direction, wherein at least one
pressure field is provided between at least one axial surface of a
toothed wheel, said axial surface lying in the direction of action
of the axial force component, and the bearing body adjoining the at
least one axial surface.
2. The toothed wheel machine as claimed in claim 1, wherein the
toothed wheels are helically toothed.
3. The toothed wheel machine as claimed in claim 1 , wherein a
pressure field is provided between those axial surfaces of the
toothed wheels which lie in the direction of action of the axial
force component and that sliding surface of the bearing body which
lies opposite the axial surfaces.
4. The toothed wheel machine as claimed in claim 3, wherein the
pressure fields have different effective areas in the axial
direction of the toothed wheels.
5. The toothed wheel machine as claimed in claim 2, wherein the
pressure fields are designed as pressure pockets.
6. The toothed wheel machine as claimed in claim 5, wherein the
pressure pockets are introduced as pressure grooves into the
sliding surfaces of the bearing body lying in the direction of
action of the axial force component.
7. The toothed wheel machine as claimed in claim 6, wherein the
sliding surface of the bearing body lying in the direction of
action of the axial force component has introduced into it a first
pressure groove, running concentrically around a first bearing eye,
and a second pressure groove, spanning a partial circle around a
second bearing eye.
8. The toothed wheel machine as claimed in claim 7, wherein the
pressure grooves are in pressure-medium communication with the high
pressure of the toothed wheel machine via connection grooves.
9. The toothed wheel machine as claimed in claim 5, wherein the
pressure pockets are introduced into those axial surfaces of the
toothed wheels which lie in the direction of action of the axial
force component.
10. The toothed wheel machine as claimed in claim 9, wherein the
pressure pockets are formed around and along a portion of the
circumference of the respective bearing shafts of the toothed
wheels.
11. The toothed wheel machine as claimed in claim 9, wherein the
pressure pockets are formed so as to run around the respective
bearing shafts of the toothed wheels.
12. The toothed wheel machine as claimed in claim 11, wherein at
least one pressure pocket is enlarged by tooth pocket sections
introduced into tooth end faces of the teeth of toothed wheel.
13. The toothed wheel machine as claimed in claim 10, wherein the
pressure pockets are supplied with pressure oil via the adjoining
bearing body.
Description
[0001] The invention relates to a hydraulic toothed wheel machine
in accordance with the preamble of patent claim 1.
[0002] EP 1 291 526 A2 shows a toothed wheel machine having a
housing in which two intermeshing toothed wheels supported in
bearing bushes or bearing bodies are arranged, the housing being
closed at the ends by a first and a second housing cover
respectively. The toothed wheels are each supported in a sliding
manner axially by two axial surfaces between the bearing bodies and
radially by respective bearing shafts accommodated in the bearing
bodies. During the operation of the toothed wheel machine,
hydraulic and mechanical forces act on the toothed wheels along the
same toothed wheel longitudinal axis in each case. To ensure that
the first bearing body, which lies in the direction of action of
the forces, is not pushed beyond the axial surfaces of the toothed
wheels, between the toothed wheels and the first housing cover, and
that only a small sliding gap occurs between the toothed wheels and
the second bearing body, a counter-force is applied to the toothed
wheels and to the first bearing body. This counter-force is larger
than the hydraulic and mechanical forces, with the result that the
first bearing body is pressed against the toothed wheels, the
toothed wheels are pressed against the second bearing body, and the
second bearing body is pressed against the second housing cover.
All the resultant forces on the bearing bodies and the toothed
wheels thus act in the direction of the second housing cover.
[0003] The counter-force on the toothed wheels is applied via
pistons acting on the bearing shafts. The pistons are accommodated
in a sliding manner, approximately coaxially with respect to the
toothed wheel longitudinal axis, in an intermediate cover arranged
between the first housing cover and the housing and rest by means
of a first piston end face against a shaft end face of the bearing
shafts which faces in the direction of the first housing cover and
are each subjected to pressure by way of a second piston end face.
The counter-force is applied to the first bearing body by way of a
pressure field formed between the bearing body and the intermediate
cover.
[0004] The disadvantage with this solution is that the entire
assembly of bearing bodies and toothed wheels is pressed onto the
second housing cover of the toothed wheel machine, with the result
that the second housing cover and the housing are subjected to very
high and uneven loads. The pressing together of the toothed wheels
and the bearing bodies results in very high wear between the axial
surfaces of the toothed wheels and the bearing bodies. Moreover,
the application of the counter-force to the bearing shafts and the
bearing bodies requires a high outlay in terms of apparatus,
involving a large number of components.
[0005] It is the object of the present invention to provide a
hydraulic toothed wheel machine which is simple in terms of the
apparatus involved and is constructed using a small number of
components and exhibits low wear.
[0006] This object is achieved by a hydraulic toothed wheel machine
in accordance with the features of patent claim 1.
[0007] According to the invention, a toothed wheel machine has a
housing for accommodating two intermeshing toothed wheels. These
are supported in a sliding manner axially by axial surfaces between
bearing bodies accommodated in the housing and radially by
respective bearing shafts accommodated in the bearing bodies.
During the operation of the toothed wheel machine, an axial force
component of a force resulting from hydraulic and mechanical forces
arising during operation acts on each toothed wheel in the same
axial direction. At least one pressure field is provided between at
least one axial surface of a toothed wheel, said axial surface
lying in the direction of action of the axial force component, and
the bearing bodies adjoining the at least one axial surface.
[0008] This solution has the advantage that a counter-force acting
against the axial force component can be applied to the toothed
wheels by means of the pressure field, without additional
components. Moreover, the pressure field reduces the axial force
component acting as a contact pressure force on the toothed wheels,
thereby reducing the sliding friction between the toothed wheels
and the bearing bodies lying in the direction of action of the
axial force component and minimizing wear.
[0009] The toothed wheels are preferably helically toothed.
[0010] In a preferred embodiment, a pressure field is provided
between each of those axial surfaces of the toothed wheels which
lie in the direction of action of the axial force component and
those sliding surfaces of the bearing body which lie opposite the
axial surfaces. This has the advantage that the pressure fields can
be of different sizes, making it possible to apply different
pressure forces to each toothed wheel.
[0011] The pressure fields can simply be designed as pressure
pockets.
[0012] It is advantageous if the pressure pockets are introduced as
cheap-to-produce pressure grooves into the sliding surfaces of the
bearing body lying in the direction of action of the axial force
component.
[0013] The sliding surface of the bearing body lying in the
direction of action of the axial force component preferably has
introduced into it a first pressure groove, running concentrically
around a first bearing eye, and a second pressure groove, spanning
a partial circle around a second bearing eye, and different
effective areas of the pressure grooves are thereby obtained.
[0014] It is advantageous if the pressure grooves are in
pressure-medium communication with the high pressure of the toothed
wheel machine via connection grooves. This enables the pressure
force acting in the pressure grooves to be linked to the operating
conditions of the toothed wheel machine.
[0015] In another preferred embodiment, the pressure pockets are
introduced into those axial surfaces of the toothed wheels which
lie in the direction of action of the axial force component.
[0016] To enable them to be produced in a simple manner, the
pressure pockets are formed around and along a portion of the
circumference of the respective bearing shafts of the toothed
wheels and, as a result, the leakage gap that forms is small
too.
[0017] To enable the toothed wheels to be supplied with a uniform
pressure, it is advantageous if the pressure pockets are formed so
as to run around the respective bearing shafts of the toothed
wheels.
[0018] To increase the effective area of the pressure pockets, at
least one pressure pocket is preferably enlarged by tooth pocket
sections introduced into the tooth end faces of the teeth of the
toothed wheel.
[0019] The pressure pockets can be supplied with pressure oil via
the adjoining bearing body, the pressure pockets being in
pressure-medium communication with the high pressure of the toothed
wheel machine, for example.
[0020] Other advantageous developments of the invention form the
subject matter of further subclaims.
[0021] A number of illustrative embodiments of the invention are
explained in greater detail below with reference to schematic
drawings. In the drawings:
[0022] FIG. 1 shows a simplified illustration of a toothed wheel
machine in a longitudinal section;
[0023] FIG. 2 shows a simplified illustration of an assembly of
bearing bodies and toothed wheels of the toothed wheel machine from
FIG. 1, in a side view;
[0024] FIG. 3 shows a simplified illustration of bearing bodies and
toothed wheels of the toothed wheel machine according to a first
illustrative embodiment in a longitudinal section;
[0025] FIG. 4 shows a plan view of the bearing body from FIG. 3;
and
[0026] FIG. 5 shows a plan view of the toothed wheels of the
toothed wheel machine according to a second illustrative
embodiment.
DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENTS
[0027] FIG. 1 shows a hydraulic machine, embodied as a toothed
wheel machine 1, according to one illustrative embodiment in a
longitudinal section. This machine has a machine housing 2, which
is closed by means of two housing covers 4 and 6. Housing cover 6
of the toothed wheel machine 1, which is on the right in FIG. 1, is
penetrated by a first bearing shaft 8, on which a first toothed
wheel 10 is arranged within the machine housing 2. The first
toothed wheel 10 is in engagement with a second toothed wheel 12 by
way of helical toothing 14, toothed wheel 12 being arranged on a
second bearing shaft 16 for conjoint rotation therewith. The first
and second bearing shafts 8 and 16 are each guided in two plain
bearings 18, 20 and 22, 24 respectively. The plain bearings 20, 24
on the right in FIG. 1 are accommodated in a bearing body 26, and
the plain bearings 18, 22 on the left in FIG. 1 are accommodated in
a bearing body 28. The toothed wheels 10 and 12 are each supported
in a sliding manner in the axial direction by respective first
axial surfaces 30 and 32 on the second bearing body 26 (on the
right in FIG. 1) and by respective second axial surfaces 34 and 36
on the bearing body 28 on the left. To reduce friction, sliding
surfaces between the toothed wheels 10, 12 and the bearing bodies
26, 28 can be provided with an antifriction coating, such as
MoS.sub.2, graphite or PTFE. Respective end faces 38 and 40 of the
bearing bodies 26 and 28 face the housing covers 6 and 4.
[0028] The housing covers 4, 6 are aligned on the machine housing 2
by means of centering pins 42. A housing seal 44 is arranged
between the housing covers 4 and 6 and the machine housing 2.
Respective axial field seals 46 are furthermore inserted into the
end faces 38 and 40 of the bearing bodies 26 and 28 to separate a
high-pressure zone from a low-pressure zone of the toothed wheel
machine 1. A shaft seal ring 48 seals off the first bearing shaft 8
where it passes through the housing cover 6 on the right in FIG.
1.
[0029] Hydraulic and mechanical forces arise during the operation
of the toothed wheel machine 1, this being illustrated
schematically in detail in FIG. 2 below.
[0030] FIG. 2 shows a simplified illustration, in side view, of the
assembly of toothed wheels 10 and 12 and bearing bodies 26 and 28
in order to illustrate the hydraulic forces that arise during
operation and the mechanical forces that essentially act due to the
helical toothing in the toothed wheel machine 1 from FIG. 1. A
force component of a hydraulic force acts in the same axial
direction on both toothed wheels 10, 12, toward the left in FIG. 2.
In addition, a driving toothed wheel, which is the upper toothed
wheel 10 in FIG. 2, is acted upon by a mechanical force component
of a mechanical force in the direction of action of the hydraulic
force component, and a driven toothed wheel, which is the lower
toothed wheel 12 in FIG. 2, is acted upon by a mechanical force
component counter to the direction of action of the hydraulic force
component. The hydraulic and mechanical force components each
produce a resultant axial force component 47, 49 in the same
direction (to the left in FIG. 2) on both toothed wheels 10, 12,
although there is a difference in magnitude.
[0031] The toothed wheels 10 and 12 subjected to axial force
components 47, 49 are each supported by axial surfaces 34 and 36,
respectively, on the bearing body 28 on the left in FIG. 2. The
right-hand bearing body 26 is not subject to the axial force
components acting on the toothed wheels 10, 12. To reduce wear
between the toothed wheels 10, 12 and the bearing body 28 on the
left in FIG. 2, a counter-force is applied to the toothed wheels,
this being indicated by dashed arrows in FIG. 2.
[0032] FIG. 3 shows a simplified illustration of the bearing bodies
26, 28 and the toothed wheels 10, 12 according to a first
illustrative embodiment of the toothed wheel machine 1 from FIG. 1
in a longitudinal section. To apply the counter-force to the
toothed wheels 10, 12, a pressure field is provided between those
axial surfaces 34, 36 of the toothed wheels 10, 12 which lie in the
direction of action of the axial force components 47, and those
sliding surfaces 50, 52 of the bearing body 28 which lie opposite
the axial surfaces 34, 36. The bearing bodies 26, 28 can be of
two-part construction, as illustrated in FIG. 3. The pressure field
is delimited by pressure grooves 54 and 56, respectively,
introduced into the sliding surfaces 50 and 52 and by the
respective axial surfaces 34 and 36. Pressure forces 58, 60 acting
on bearing body 28 and the toothed wheels 10, 12 by virtue of the
pressure field are illustrated in simplified form by double arrows
in FIG. 3, with bearing body 28 having been moved to the left to
enable the pressure forces 58, 60 to be illustrated more clearly.
The design of the pressure grooves 54, 56 can be seen in the
following figure, FIG. 4.
[0033] FIG. 4 discloses the sliding surfaces 50, 52 of the
spectacle-shaped bearing body 28 from FIG. 3 in a plan view. The
first pressure groove 54 is introduced into the sliding surface so
as to run around a bearing eye 62 at the top in FIG. 4. The second
pressure groove 56 is formed substantially in the high pressure
zone of the toothed wheel machine 1 from FIG. 1, spanning a partial
circle around a lower bearing eye 64. The pressure grooves 54, 56
are in pressure-medium communication with the high pressure of the
toothed wheel machine 1 via radial grooves 66.
[0034] The pressure forces 58, 60 are applied to the toothed wheels
10, 12 and bearing body 28 by means of the respective pressure
grooves 54 and 56 introduced into the sliding surfaces 50 and 52 in
FIGS. 3 and 4. The pressure forces 58, 60 counteract the axial
force components 47, 49, thereby reducing the sliding friction and
wear between the toothed wheels 10, 12 and bearing body 28. The
size of the pressure grooves 54, 56 is designed in such a way that
the axial force components 47, 49 applied to the toothed wheels 10,
12 are thus substantially compensated for by the pressure forces
58, 60, and the toothed wheels 10, 12 are thus supported
approximately hydrostatically. The axial force component 47 at the
top in FIG. 3 is larger than the lower axial force component 49,
for which reason the upper pressure groove 54 from FIG. 4 is
designed with a larger area than the lower pressure groove 56.
[0035] FIG. 5 shows a plan view of the axial surfaces 34, 36 of the
toothed wheels 10, 12 in accordance with a second illustrative
embodiment of the toothed wheel machine 1 from FIG. 1. Here, the
pressure field is not delimited by pressure grooves 54, 56
introduced into bearing body 28 as in FIG. 3 but by respective
pressure pockets 68 and 70 introduced into the axial surfaces 34
and 36 of the toothed wheels 10 and 12. The pressure pocket 70 in
toothed wheel 12, said pocket being at the bottom in FIG. 5, is
designed as an annular groove which is introduced around the axial
surface 36 between tooth end faces 72 of teeth 74 of toothed wheel
12 and an outer circumferential surface of bearing shaft 16. In
addition to an annular groove corresponding to pressure pocket 70,
the pressure pocket 68 in toothed wheel 10, said pocket being at
the top in FIG. 5, has tooth pocket sections 76 introduced into the
tooth end faces 72, pressure pocket 68 thus being introduced into
the axial surface 34 over a large area. Pressure pocket 68 is then
delimited radially by a wall 78 running around the periphery of
toothed wheel 10. The pressure pockets 68, 70 are in
pressure-medium communication with the high pressure of the toothed
wheel machine 1 from FIG. 1 via connection grooves in the adjoining
bearing body 28 (see FIG. 1), for example.
[0036] By virtue of the pressure pockets 68, 70 in the toothed
wheels 10, 12, the pressure forces 58, 60 from FIG. 3 are
introduced in the area of action on bearing body 28 of the toothed
wheels 10, 12 subjected to axial force components 47, 49. Since the
pressure pocket 68 at the top in FIG. 4 has a larger axial pressure
application area than the lower pressure pocket 70, the pressure
force acting on the upper toothed wheel 10 is greater.
[0037] As an alternative, it is conceivable for the pressure
pockets 68, 70 from FIG. 4 to be introduced into the toothed wheels
10, 12 in such a way that they do not run around but merely span a
partial circle and have a larger radial width. This would be a way,
for example, of simplifying manufacture and reducing the size of a
leakage gap, which would result in smaller hydraulic losses.
[0038] The operation of the axial-gap and axial-force compensation
explained above is independent of the construction of the bearing
elements used and can therefore be employed for all components
suitable for axial sealing of toothed wheel machines. The same
applies also to the type of toothing and the parameters thereof.
Such axial-gap and axial-force compensation can be employed both in
external and internal toothed wheel machines.
[0039] The toothed wheel machine can be used as a gear pump or
motor.
[0040] The disclosure is of a toothed wheel machine having a
housing for accommodating two intermeshing toothed wheels. These
are supported in a sliding manner axially by axial surfaces between
bearing bodies accommodated in the housing and radially by
respective bearing shafts accommodated in the bearing bodies.
Hydraulic and mechanical forces arise during the operation of the
toothed wheel machine, and an axial force component of these forces
acts in the same axial direction on each toothed wheel. To
counteract this axial force component, a pressure field is provided
between at least one axial surface of a toothed wheel, said axial
surface lying in the direction of action of the axial force
component, and the bearing body adjoining the at least one axial
surface.
* * * * *