U.S. patent application number 12/438819 was filed with the patent office on 2009-08-13 for axial piston machine and control plate for an axial piston machine.
This patent application is currently assigned to ROBERT BOSCH GMBH. Invention is credited to Martin Zug.
Application Number | 20090199705 12/438819 |
Document ID | / |
Family ID | 39149348 |
Filed Date | 2009-08-13 |
United States Patent
Application |
20090199705 |
Kind Code |
A1 |
Zug; Martin |
August 13, 2009 |
AXIAL PISTON MACHINE AND CONTROL PLATE FOR AN AXIAL PISTON
MACHINE
Abstract
In the case of a control plate for an axial piston machine
having at least two control openings (31, 32), by means of which
cylinder bores (9) of a cylinder drum (4) rotatably mounted in a
housing (2) are alternately connected, on rotation of the cylinder
drum (4), to a high-pressure connection and a low-pressure
connection, an outwardly extending extension surface (40) is formed
on a partial region of the outer circumference of the control plate
(20), the extension surface being designed for defined bearing
against a holding element (52, 53) of the axial piston machine (1)
in order to achieve a rotation locking for the control plate
(20).
Inventors: |
Zug; Martin; (Hirrlingen,
DE) |
Correspondence
Address: |
SCULLY SCOTT MURPHY & PRESSER, PC
400 GARDEN CITY PLAZA, SUITE 300
GARDEN CITY
NY
11530
US
|
Assignee: |
ROBERT BOSCH GMBH
Stuttgart
DE
|
Family ID: |
39149348 |
Appl. No.: |
12/438819 |
Filed: |
December 10, 2007 |
PCT Filed: |
December 10, 2007 |
PCT NO: |
PCT/EP2007/010759 |
371 Date: |
February 25, 2009 |
Current U.S.
Class: |
92/13 ;
91/504 |
Current CPC
Class: |
F04B 1/205 20130101;
F04B 1/2042 20130101; F04B 1/2021 20130101 |
Class at
Publication: |
92/13 ;
91/504 |
International
Class: |
F01B 13/04 20060101
F01B013/04; F01B 3/00 20060101 F01B003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 11, 2006 |
DE |
10 2006 058 356.6 |
May 24, 2007 |
DE |
10 2007 024 174.9 |
Claims
1. Control plate for an axial piston machine having at least two
control openings, by means of which cylinder bores of a cylinder
drum rotatably mounted in a housing are alternately connected, on
rotation of the cylinder drum, to a high-pressure connection and a
low-pressure connection, wherein an outwardly extending extension
surface is formed on a partial region of the outer circumference of
the control plate, the extension surface being designed for defined
bearing against a holding element of the axial piston machine in
order to achieve a rotation locking for the control plate.
2. Control plate according to claim 1, wherein the extension
surface has a straight edge region for bearing against a plane wall
of the holding element.
3. Control plate according to claim 2, wherein the extension
surface has an edge recess.
4. Control plate according to claim 3, wherein the recess is
designed to cooperate with an oval or cylindrical holding
element.
5. Control plate according to claim 1, wherein an indentation is
formed in the edge region of the extension surface and/or in an
edge region of the control plate opposite the extension
surface.
6. Control plate according to claim 1, wherein a through-opening is
formed in the control plate, the radially inner edge of the control
plate being designed as a centring surface which centres the
control plate on a centring body on the housing.
7. Control plate according to claim 6, wherein the centring surface
is composed of a plurality of partial surfaces formed on segments
of the inner edge of the control plate which extend radially
inwardly into the through-opening and are separated from one
another by recesses.
8. Control plate according to claim 7, wherein the radial extent of
the individual recesses is of such a size that a gap results in the
region of the recesses between the control plate and the centring
body.
9. Control plate according to claim 1, wherein the outer edge
region of the control plate is reduced in the radial direction in
the region of the at least one control opening connected to the
low-pressure connection.
10. Control plate according to claim 1, wherein it is formed by a
stamping.
11. Axial piston machine having a cylinder drum which is rotatably
mounted in a housing and in which are made cylinder bores, in which
pistons are axially displaceably arranged, the cylinder bores
having openings towards an end side of the cylinder drum, which are
alternately in connection, on a rotation of the cylinder drum, with
a high-pressure connection and low-pressure connection via at least
two control openings of a control plate, wherein the control plate
is designed according to claim 1.
12. Control plate according to claim 11, wherein the machine is
designed as a swash-plate machine, the holding element being formed
by a setting piston guide.
13. Axial piston machine according to claim 11, wherein a
through-opening is formed in the control plate, and in that the
cylinder drum is arranged on a shaft in a manner fixed against
relative rotation, the shaft being mounted in the housing on the
side of the control plate, and the control plate being centred on
an outer bearing race of a rolling bearing by a centring surface
formed on the inner edge of the control plate.
Description
[0001] The present invention relates to an axial piston machine and
to a control plate for such an axial piston machine.
[0002] In axial piston machines, pistons which are arranged
longitudinally displaceably in cylinder bores of a cylinder drum
perform a stroke movement on each revolution of the cylinder drum,
which movement consists of a suction stroke and a pressure stroke.
In order to ensure a rotationally synchronous connection between
the cylinder drum and the corresponding working line of the axial
piston machine, a so-called control plate is situated at the end
side of the cylinder drum, in which control plate there are
generally formed kidney-shaped control openings for connecting the
cylinder drum to a high-pressure connection and a low-pressure
connection of the axial piston machine.
[0003] A conventional control plate, as is known from the prior art
and described, by way of example in a similar form, in DE 102 51
552 B3, is illustrated in FIGS. 5 to 7. The control plate 100 has
an outside diameter which corresponds to the inside diameter of a
corresponding housing component of the axial piston machine. In the
direction of the side facing away from the cylinder drum, the
control plate 100 is supported on a housing cover, in which the
high-pressure connection and the low-pressure connection of the
axial piston machine are formed. The control plate 100 has a
plurality of control openings 101 and 102 distributed over its
circumference, which are provided for connecting the cylinder drum
to the low-pressure connection and to the high-pressure connection,
respectively. Besides these control openings 101, 102, the
so-called kidney suction opening and the so-called kidney pressure
openings, the control plate 100 furthermore has a central cutout
which is penetrated by a shaft of the axial piston machine
connected to the cylinder drum in a manner fixed against relative
rotation. Adjoining this central cutout are two lateral
indentations 103 which form a passage for leakage oil. Furthermore,
in the edge region there is formed a groove 104, as can be seen in
particular from the illustration in FIG. 7, which enables a
rotation-locked positioning of the control plate 100. According to
the illustration in FIG. 6, this groove 104 cooperates with a pin
110 mounted in the housing of the machine, ensuring that, on the
one hand, the plate 100 cannot be fitted in the axial piston
machine in a manner rotated by 180.degree. and, on the other hand,
no rotation of the plate 100 occurs during operation either.
[0004] Such control plates have proved their worth many time in the
past, but require a relatively complex working process for their
production. In this process, the plates are usually produced from
slugs or rough stampings or forgings by machining, the appropriate
parts being completely machined on all surfaces. In this working
process, in particular the kidney suction opening 101, the kidney
pressure openings, the leakage oil passages 103 and the groove 104
for the rotation locking are cut out.
[0005] The object on which the present invention is now based is to
specify a novel distributing or control plate for an axial piston
machine which, on the one hand, is at least equivalent to the known
control plates as regards its operating properties, but, on the
other hand, can be produced more simply and cost-effectively.
[0006] The object is achieved according to the invention by a
control plate for an axial piston machine having the features of
claim 1 and an axial piston machine having the features of claim
11. Advantageous developments of the invention are the
subject-matter of the dependent claims.
[0007] The solution according to the invention is based on the idea
of configuring the control plate in such a way that an outwardly
extending extension surface is formed on a partial region of the
outer circumference of the control plate, the extension surface
being designed in such a way that it enables a defined bearing
against a holding element of the axial piston machine in order to
achieve a rotation locking for the control plate. For this purpose,
the extension surface may, for example, have a straight edge region
which is suitable for bearing against a plane wall of a
corresponding holding element. Furthermore, an edge recess in the
extension surface would also be conceivable or a protuberance,
which can cooperate, for example, with an oval or cylindrically
configured holding element or with a corresponding recess in the
holding element, respectively.
[0008] According to the invention, a control plate for an axial
piston machine having at least two control openings, by means of
which cylinder bores of a cylinder drum rotatably mounted in a
housing are alternately connected, on rotation of the cylinder
drum, to a high-pressure connection and a low-pressure connection,
is accordingly specified, it being provided according to the
invention that an outwardly extending extension surface is formed
on a partial region of the outer circumference of the control
plate, the extension surface being designed for defined bearing
against a holding element of the axial piston machine in order to
achieve a rotation locking for the control plate.
[0009] The advantage of the solution according to the invention is
that the known pin-and-groove connection for achieving the rotation
locking can be dispensed with. In contrast to the groove
illustrated in FIGS. 5 and 7, in the control plate according to the
invention the rotation locking is achieved by a special shaping of
the outer circumference or outer contour of the control plate,
which affords the advantage that the edge recesses provided, for
example, for this can be designed to be continuous, i.e. over the
entire thickness of the control plate. This, in turn, means that it
is possible to produce the control plate according to the invention
in a simple manner by a stamping process, during which the outer
contour, the inner contour and the kidney regions of the control
plate can be created directly. All that is then still required is a
finishing of the two plane bearing surfaces of the control plate,
which affords significant advantages in the production. As an
alternative to this, the control plate could also be produced by
laser cutting, in which case a finishing of the plane surfaces is
then unnecessary, since a high-quality input stock with the
required surface finish can be used. Both methods can be used only
to a limited extent for the control plate according to the prior
art, since the formation of the groove for the rotation locking can
only be produced by machining the plate.
[0010] Developments of the concept according to the invention
relate, in particular, to measures which can additionally reduce
the material expenditure for and the space requirement of the
control plate. In this regard, it may be provided, for example,
that the outer edge region of the control plate is reduced in the
radial direction in the region of the at least one control opening
connected to the low-pressure connection. Furthermore, the radially
inner edge of the control plate may be designed as a centring
surface which centres the control plate on a centring body on the
housing. This centring surface may be composed of a plurality of
partial surfaces formed on segments of the inner edge of the
control plate which extend radially inwardly into the
through-opening. The radial extent of the individual recesses is,
in this case, preferably of such a size that a gap results in the
region of the recesses between the control plate and the centring
body, which gap is suitable for allowing a leakage fluid which has
accumulated in the interior of the cylinder drum to pass
through.
[0011] According to the invention, an axial piston machine having a
cylinder drum which is rotatably mounted in a housing and in which
are made cylinder bores, in which pistons are axially displaceably
arranged, the cylinder bores having openings towards an end side of
the cylinder drum, which are alternately in connection, on a
rotation of the cylinder drum, with a high-pressure connection and
low-pressure connection via at least two control openings of a
control plate, is furthermore proposed, the control plate being
designed according to the above-described concept according to the
invention. Advantageously, the machine is designed as a swash-plate
machine, it then being possible for the holding element for the
rotation-locked positioning of the control plate to be formed by
the setting piston guide.
[0012] The invention will be explained in more detail below with
reference to the accompanying drawings, in which:
[0013] FIG. 1 shows a schematic illustration of an axial piston
machine configured according to the invention;
[0014] FIG. 2 shows an illustration of a first exemplary embodiment
of a control plate according to the invention;
[0015] FIG. 3 shows the arrangement of the control plate according
to the invention of FIG. 2 in the axial piston machine;
[0016] FIG. 4 shows the arrangement of an alternative embodiment of
a control plate according to the invention in an axial piston
machine, and
[0017] FIGS. 5 to 7 show the configuration and arrangement of a
control plate of an axial piston machine according to the prior
art.
[0018] The axial piston machine according to the invention which is
illustrated in FIG. 1 and provided generally with the reference
symbol 1 is configured largely identically to the axial piston
machine known from DE 102 51 552 B3. The construction and function
of the known components of the machine 1 will therefore be merely
briefly summarised in the following.
[0019] The axial piston machine 1 has a shaft 3 which is rotatably
mounted in a housing 2 and on which a cylinder drum 4 is arranged,
the cylinder drum 4 and the shaft 3 being connected to one another
in a manner fixed against relative rotation. The shaft 3 penetrates
the cylinder drum 4 and is mounted on both sides of the cylinder
drum 4 with the aid of a rolling bearing 5 and 6, respectively, the
lower rolling bearing 6 having in particular an outer bearing race
7 which is inserted into a corresponding recess of a housing cover
8 of the axial piston machine 1.
[0020] A plurality of cylinder bores 9 are formed in the cylinder
drum 4 in a manner distributed over the circumference, the centre
axes of the cylinder bores 9 running parallel or obliquely to the
centre axis of the shaft 3. Inserted axially displaceably in these
bores 9 are pistons 10 having, on the side facing away from the
housing cover 8, a spherical head 11 which cooperates with a
corresponding recess of a slide shoe 12 to form a knuckle joint.
The piston 10 is supported on a swash plate 13 by means of the
slide shoe 12, so that on one revolution of the cylinder drum 4,
the pistons 10 accordingly perform an alternating stroke movement.
The length of stroke is predetermined here by the position of the
swash plate 13, which can be adjusted about a tilting axis running
perpendicularly to the longitudinal axis of the shaft 3. For this
purpose, there is provided an adjusting device 14 with a piston 50
which cooperates at its two ends with the swash plate 13 on the one
hand and with a setting piston guide 51 on the other hand. The
configuration in particular of this cylinder-like or pot-like
setting piston guide 51 will be explained in more detail at a later
time.
[0021] The cylinder drum 4 has a central opening 15, in which there
is arranged a compression spring 16 which is clamped between a
first spring bearing 17 and a second spring bearing 18. The first
spring bearing 17 is fixed here in the axial direction on the shaft
3, whereas the second spring bearing 18, in contrast, is formed by
a Seeger circlip ring inserted into a groove of the cylinder drum
4. Through the force of the compression spring 16, the cylinder
drum 4 is displaced in the axial direction to such an extent that
its end face 19 bears sealingly on the control plate 20.
[0022] The control openings, not evident in the sectional
illustration according to FIG. 1, of the control plate 20 are, on
each side facing away from the cylinder drum, in permanent contact
with at least one high-pressure connection and one low-pressure
connection of the axial piston machine 1. The cylinder bores 9 of
the drum 4 are open towards the end face 19 of the cylinder drum 4
via corresponding openings 21, these openings 21, on rotation of
the drum 4, passing over the control plate and thereby being
alternately connected to the control openings for the high-pressure
connection and the low-pressure connection, respectively.
[0023] The position of the control plate 20 is fixed with respect
to the shaft 3 firstly by a centring surface 29, the configuration
of which will be explained in more detail below. A through-opening
of the control plate 20 has, for this purpose, a radial extent
corresponding to the outer radial extent of a centring body which
is connected to a housing component. In the exemplary embodiment
illustrated, the centring body is formed by the outer bearing race
7 of the rolling bearing 6. In the axial direction, the control
plate 20 is supported on the housing cover 8, and, to avoid
leakage, the control plate 20 has a sealing surrounding area 28
which is formed on the side of the control plate 20 facing away
from the cylinder drum 4 and cooperates sealingly with the surface
of the housing cover 8.
[0024] For a correct operation of the axial piston machine 1,
besides a centred arrangement of the control plate 20 an
appropriate orientation is also required, it being necessary to
ensure that no rotation of the control plate 20 takes place during
the operation of the machine 1 either. While the pin-and-groove
connection described in the introduction is used for this purpose
in the prior art, according to the invention it is now proposed to
configure the control plate 20 in a special way, so that a
rotation-locked arrangement is again achieved, but the
pin-and-groove connection can be dispensed with and accordingly the
production of the control plate 20 can be simplified. A first
exemplary embodiment of an appropriately configured control plate
will now be explained with reference to FIGS. 2 and 3.
[0025] First of all, in FIG. 2 the control plate 20 with the
central opening 30 and the control opening 31 for the low-pressure
connection and three control openings 32 for the high-pressure
connection can be seen. The central through-opening 30 has in this
case a diameter corresponding to the outer circumference of the
bearing race 7 of the rolling bearing 6. The inner edge 33 of the
through-opening 30 accordingly forms the above-mentioned centring
surface 29. The through-opening 30 is furthermore widened by two
recesses 34 and 35, between each of which segments are formed, so
that the centring surface 29 is ultimately formed by the partial
surface 29.1 and 29.2 on the segments. As a result of the recesses
34 and 35, a gap 22 (see FIG. 1) is formed partially at the
circumference of the outer bearing race 7, through which gap a
leakage fluid can pass.
[0026] The special feature, according to the invention, of the
control plate 20 consists in an outwardly extending extension
surface 40 in the upper region of the outer circumference. This
extension surface 40 is configured in a special way in its edge
region 41, in order to enable a defined bearing relative to a
holding element of the axial piston machine. This enables a
rotation-locked arrangement of the control plate 20, despite
dispensing with the pin-and-groove connection.
[0027] In the exemplary embodiment of FIGS. 2 and 3, the extension
surface 40 has a straight edge region 41, which can accordingly
cooperate with a plane wall of a holding element. According to the
illustration in FIG. 3, provision is preferably made, for this
purpose, for the setting piston guide 51 already mentioned above to
be used as the holding element. This setting piston guide has a
cylinder 52, the lower end of which rests on a disc 53. This disc
53 is in this case likewise cut off straight in its edge region 54,
so that the edge region 41 of the extension 40 of the control plate
20 can bear in a plane manner against the edge region of the disc
54, as illustrated in FIG. 3. This prevents in an effective way a
rotation of the control plate 20 during the operation of the axial
piston machine 1.
[0028] The advantage of the configuration, according to the
invention, of the control plate 20 is that the corresponding
configuration of the edge region 41 of the extension 40 can extend
over the entire height or thickness of the control plate 20. This
enables production of the control plate 20 in a relatively simple
and cost-effective manner. For example, a simple stamping-out of
the control plate 20 would be conceivable, during which the outer
contour, the inner contour and the kidney regions could be created
at the same time. In this case, all that would still be required is
a finishing on the two plane bearing surfaces of the control plate
20. As an alternative to this, however, an appropriately shaped
blank could also be machined by laser cutting, in which case a
finishing of the plane surfaces is then no longer required, since a
high-quality input stock with the necessary surface finish can
already be used. Both variants are significantly simpler to carry
out than the machining of slugs or rough stampings or forgings
which has been required hitherto for the production of control
plates. At the same time, however, the functionality of the control
plate is fully preserved, since the appropriate configuration of
the edge region 41 of the extension 40 means that the desired
rotation locking is achieved as before.
[0029] Further measures concerning the shaping of the control plate
20 which additionally optimise the material expenditure and the
space requirement can be gathered from FIGS. 2 and 3. Thus, on the
one hand, provision may be made for the outer region 42 of the
control plate to be reduced in the radial direction in the region
of the low-pressure control opening 31. As a result, on the one
hand the space requirement and on the other hand the material
expenditure is thus reduced. Furthermore, openings are formed by
appropriate indentations 43 and 44 in the edge region 41 of the
extension surface and/or in an edge region of the control plate 20
opposite the extension surface 40, which openings serve to carry
off the pumping leakage oil without loss.
[0030] FIG. 4 shows an alternative embodiment of a control plate 20
according to the invention which differs in the configuration of
the edge region of the extension surface 40. In this case, the
control piston guide 51 is designed merely as an upwardly extending
cylinder 52, the edge region 41 of the extension surface 40 then
having an edge recess 45 which cooperates with the cylindrical
outer contour of the cylinder 52. Again, a rotation of the control
plate 20 during the operation of the axial piston machine is
precluded by this configuration. Furthermore, it would be
conceivable to configure the extension surface, in the edge region,
with a protuberance or projection which then cooperates with a
corresponding depression or recess in the holding element.
[0031] Overall, therefore, the present invention opens up the
possibility of simpler and more cost-effective production of
control plates for axial piston machines. At the same time,
however, an exact arrangement and orientation of the control plate
in the axial piston machine is ensured as before.
* * * * *