U.S. patent application number 13/637397 was filed with the patent office on 2013-01-24 for control valve having a curved spring band serving as a non-return valve.
This patent application is currently assigned to SCHAEFFLER TECHNOLOGIES AG & CO. KG. The applicant listed for this patent is Lars Buchmann, Jens Hoppe. Invention is credited to Lars Buchmann, Jens Hoppe.
Application Number | 20130019830 13/637397 |
Document ID | / |
Family ID | 44140688 |
Filed Date | 2013-01-24 |
United States Patent
Application |
20130019830 |
Kind Code |
A1 |
Hoppe; Jens ; et
al. |
January 24, 2013 |
CONTROL VALVE HAVING A CURVED SPRING BAND SERVING AS A NON-RETURN
VALVE
Abstract
A control valve, in particular a proportional valve for
controlling a device for adjusting the rotation angle position of a
camshaft with respect to a crankshaft of an internal combustion
engine, including a hollow-cylindrical valve housing (1), which has
a plurality of openings (2) that are arranged circumferentially in
a radial plane for connecting to a pressure medium connection (P)
and can be closed via a non-return valve (4) designed as a curved
spring band (3). According to the invention, the openings (2)
arranged in a radial plane are arranged at different angle
distances to each other, and the shape and the rotation angle
position of the curved spring band (3) serving as a non-return
valve (4) is matched thereto.
Inventors: |
Hoppe; Jens; (Erlangen,
DE) ; Buchmann; Lars; (Erlangen, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Hoppe; Jens
Buchmann; Lars |
Erlangen
Erlangen |
|
DE
DE |
|
|
Assignee: |
SCHAEFFLER TECHNOLOGIES AG &
CO. KG
Herzogenaurach
DE
|
Family ID: |
44140688 |
Appl. No.: |
13/637397 |
Filed: |
April 5, 2011 |
PCT Filed: |
April 5, 2011 |
PCT NO: |
PCT/EP2011/055231 |
371 Date: |
September 26, 2012 |
Current U.S.
Class: |
123/90.17 |
Current CPC
Class: |
F01L 1/34 20130101; F16K
15/16 20130101; F01L 1/46 20130101; F01L 2001/34426 20130101; F01L
1/344 20130101 |
Class at
Publication: |
123/90.17 |
International
Class: |
F01L 1/344 20060101
F01L001/344 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 26, 2010 |
DE |
10 2010 018 200.1 |
Claims
1. A control valve for controlling a device for adjusting a
rotational angle position of a camshaft with respect to a
crankshaft of an internal combustion engine, comprising a
hollow-cylindrical valve housing and, for connection to a pressure
medium connection (P), the housing valve has a plurality of
openings which are arranged circumferentially in a radial plane and
are closable via a non-return valve formed by a curved spring band
the openings which are arranged in the radial plane are arranged at
different angular distances from one another, and a shape and a
rotational angle position of the curved spring band serving as the
non-return valve are matched to said angular distances.
2. The control valve as claimed in claim 1, wherein the curved
spring band serving as the non-return valve has an open oval
shape.
3. The control valve as claimed in claim 1, wherein the valve
housing for receiving the curved spring band in a region of the
openings has different wall thicknesses such that an at least
partially encircling groove having a varying groove depth is formed
on an outer or inner circumferential side of the valve housing.
4. The control valve as claimed in claim 3, wherein a width of the
groove substantially corresponds to a width of the spring band.
5. The control valve as claimed in claim 1, wherein opening and
closing characteristics of the non-return valve are adjustable via
a spring strength of the curved spring band.
6. The control valve as claimed in claim 1, wherein the pressure
medium connection (P) is formed as an at least partially encircling
groove arranged on an outer circumferential side of the valve
housing.
Description
FIELD OF THE INVENTION
BACKGROUND
[0001] The invention relates to a control valve, in particular to a
proportional valve for controlling a device for adjusting the
rotational angle position of a camshaft with respect to a
crankshaft of an internal combustion engine. A control valve of
this type has a valve housing which is of hollow-cylindrical design
and is intended for receiving an axially displaceable control
piston, the axial displacement of which causes a pressure medium
connection to be connected to or disconnected from at least one
working connection. For this purpose, the outer circumferential
side of the control piston has control edges which interact with
valve housing openings arranged on the circumferential side.
[0002] Control valves of the abovementioned type are used, for
example, for controlling a device for the rotational angle position
of a camshaft with respect to a crankshaft of an internal
combustion engine. The camshaft serves to actuate the gas exchange
valves, the opening or closing time of which is to be set depending
on the current range of performance characteristics of the engine,
in particular depending on the current rotational speed or load
thereof, in order to optimize the engine efficiency. For this
purpose, the rotational angle position of the camshaft with respect
to the crankshaft is adjusted via a device which is actuatable
electrically, hydraulically or pneumatically. The control valve
provided in the present case is intended to be usable in particular
for controlling such a hydraulically actuatable adjusting
device.
[0003] EP 1 291 563 A2 discloses a control valve of the
above-mentioned type having a non-return valve integrated in the
valve housing. The non-return valve consists of an annularly curved
spring band which serves at the same time as a closing element and
as a spring element. The curved spring band is placed into an
annular groove formed on the outer or inner circumferential side of
the valve housing such that said spring band undergoes elastic
deformation upon pressurization in the opening direction and opens
up bores formed in the valve housing or in a sleeve surrounding the
valve housing for the passage of an operating medium while said
spring band resumes the original shape thereof and closes the bores
upon pressurization in the closing direction.
[0004] The non-return valve serves to avoid the transmission of
pressure pulsations which are operationally induced to arise in the
camshaft adjuster and--without a non-return valve--could pass back
via the working and pressure oil connections of the control valve
into the pressure oil circuit. Since, as a rule, further
components, in particular secondary components, such as chain
adjusters, etc., are connected to the same pressurized oil circuit,
back flow of the operating medium may result in damage to the
further components. At the same time, the non-return valve serves
to support pressure pulsations, thus increasing the torsional
rigidity, i.e. the positional stability of the adjusting
device.
SUMMARY
[0005] It is the object of the present invention to develop a
control valve having a non-return valve in such a manner that a
defined opening and closing of the non-return valve is ensured over
the long term. In addition, the control valve is intended to be
constructed in a simple manner and to be producible
cost-effectively.
[0006] To achieve the object, a control valve having one or more of
the features of the_invention is proposed. Advantageous
developments of the invention are provided below.
[0007] For connection to a pressure medium connection P, the valve
housing, which is of hollow-cylindrical design, of the proposed
control valve has a plurality of openings which are arranged
circumferentially in a radial plane and are closable via a
non-return valve designed as a curved spring band. According to the
invention, the openings arranged in a radial plane are arranged at
different angular distances from one another, and the shape and the
rotational angle position of the curved spring band serving as the
non-return valve are matched to said angular distances. The
different angular distances between the openings formed in the
valve housing result in a non-rotationally-symmetrical arrangement
of the openings and therefore in a non-rotationally-symmetrical
design of the valve housing. In this case, an arrangement of the
openings at different angular distances from one another is also to
be understood as meaning an arrangement in which only one angular
distance is designed to be larger or smaller than the other angular
distances. For example, one angular distance can be selected to be
of a size such that a concentration of the openings occurs in a
sector extending over a certain angular range while a further
sector is optionally formed without openings. The concentration of
the openings on one side or in a certain sector region of the valve
housing predetermines a preferred flow direction of the operating
medium and therefore an orientation of the curved spring band, in
which the spring band and the openings interact in an optimum
manner. This has to apply in particular if--as provided--the shape
and the rotational angle position of the curved spring band are
furthermore matched to the asymmetrical arrangement of the
openings. A high throughflow rate and a simultaneously small
pressure drop can therefore be brought about even given a small
opening stroke of the spring band.
[0008] In order to match the shape of the spring band to the
asymmetrical arrangement of the openings in the valve housing,
provision is made, according to a preferred embodiment of the
invention, for the curved spring band serving as a non-return valve
to have an open oval shape. It is ensured by the open shape that
the spring element can be sufficiently elastically deformed in
order to produce an opening stroke. The oval shape substantially
predetermines an orientation of the spring band with respect to the
openings formed in the valve housing. Furthermore, given an
appropriate design of a spring band receptacle, the oval shape can
be used for securing the rotational angle position of the spring
band with respect to the valve housing, thus ensuring an optimum
interaction of openings and spring band even over the long
term.
[0009] Furthermore preferably, the valve housing for receiving the
curved spring band in the region of the openings has different wall
thicknesses such that an at least partially encircling groove
having a varying groove depth is formed on the outer or inner
circumferential side of the valve housing. The spring band is
preferably arranged in the interior of the valve housing. In this
case, a groove into which the spring band can be placed is
furthermore formed preferably on the inner circumferential side in
the region of the openings. The groove depth of the groove varies
such that the groove base firstly rises, then drops. The groove
depth may also peter out entirely such that the groove base
corresponds to the inner wall of the valve housing. The groove is
then not of encircling design. The valve housing preferably has an
oval shape in cross section in the region of the groove in a manner
corresponding to the shape of the spring band such that the latter
bears in an encircling manner against the groove base. In addition,
the corresponding oval shape of the spring band and groove brings
about a securing of the rotational angle position of the spring
band. The formation of a groove for receiving the spring band
furthermore has the advantage that, due to the form-fitting
connection, the axial position of the spring band is also
secured.
[0010] As an alternative, the curved spring band serving as the
non-return valve may also, however, be inserted into a groove on
the outer circumferential side of the valve housing or into a
groove on the inner circumferential side of a receiving bore of a
camshaft or of a cylinder head and interact in a corresponding
manner with the openings of the valve housing and/or with openings
of the receiving bore. In these cases too, the spring band is
preferably placed into a groove, the groove depth of which varies
in order to achieve an oval groove shape in the cross section of
the valve housing or in the receiving bore, said groove shape being
matched to the oval shape of the spring band.
[0011] Furthermore preferably, the width of the groove, which is
provided for receiving the spring band, in the valve housing
substantially corresponds to the width of the spring band. As a
result, the axial position of the spring band is fixed. However,
this may also mean that the groove width is optionally selected to
be slightly larger in order to facilitate the insertion of the
spring band.
[0012] When the non-return valve is designed as a curved spring
band, the spring band serves at the same time as a closing element
and as a spring element. The spring band therefore combines the
functions of closing element and spring element in one component.
Furthermore, the opening and closing characteristics of the
non-return valve are adjustable via the spring strength of the
curved spring band. The spring strength is predetermined in
particular by the hinge strength of the spring band. The hinge
strength may also be varied, for example, over the circumference of
the curved spring band.
[0013] The pressure medium connection P is advantageously designed
as an at least partially encircling groove arranged on the outer
circumferential side of the valve housing. For the sake of
simplicity, the groove may be designed as an annular groove. In a
corresponding manner, further annular grooves may be arranged on
the outer circumferential side of the valve housing, said annular
grooves forming further connections, for example the working
connections A and B.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] A preferred embodiment of the invention is described in more
detail below with reference to the drawings, in which:
[0015] FIG. 1 shows a side view and a top view of a curved spring
band of a control valve according to the invention,
[0016] FIG. 2 shows a longitudinal section and a cross section
through a valve housing of a control valve according to the
invention,
[0017] FIG. 3 shows a longitudinal section through the valve
housing of FIG. 2 with the spring band inserted upon pressurization
in the opening direction, and
[0018] FIG. 4 shows a longitudinal section through the valve
housing of FIG. 2 with the spring band inserted upon pressurization
in the closing direction.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0019] FIGS. 1 and 2 show the essential elements of a control valve
according to the invention, namely a spring band 3 usable as a
non-return valve 4, and a valve housing 1, each in an individual
illustration. In the exemplary embodiment of FIGS. 3 and 4, the
spring band 3 is inserted into a groove 5 formed on the inner
circumferential side of the valve housing 1 such that the spring
band 3 bears against the groove base of the groove 5 under a
certain radial prestress.
[0020] As can be gathered from FIG. 1, the spring band 3 usable as
the non-return valve 4 is curved to form an oval shape such that
the ends of the spring band 3 are spaced apart from each other. The
distance between the ends or the opening of the oval shape ensures
that the spring band 3 is elastically deformable within the groove
5. The width of the spring band 3 is constant and is matched to the
width of the groove 5.
[0021] As FIG. 2 shows, an ovally shaped groove 5 is formed in a
manner corresponding to the oval shape of the spring element 3 on
the inner circumferential side of the valve housing 1 (see cross
section of the valve housing) in the region of openings 2 which
serve to hydraulically connect a pressure medium connection P,
which is designed as an encircling groove 6, to working connections
A and B. In this case, the openings 2 are arranged
circumferentially at different angular distances from one another
in such a manner that the groove 5 does not have any openings 2
over a certain angular range. A main flow direction of the
operating medium is therefore predetermined, said flow direction,
together with the shape of the groove 5, predetermining a certain
orientation of the spring band 3. This ensures optimum interaction
of openings 2 and spring band 3. In addition, the groove 5 secures
the installed position of the spring band 3 against axial
displacement and against rotation.
[0022] The functioning of the non-return valve 4 is as follows:
[0023] Upon pressurization of the spring band 3 in the opening
direction (see FIG. 3) by operating medium being supplied via the
pressure medium connection P, the spring band 3 is pressed radially
inward, wherein said spring band undergoes elastic deformation and
opens up the openings 2. Even at a small opening stroke of the
spring band 3, a high throughflow rate can be obtained with little
pressure drop, i.e. low losses, since the arrangement of the
openings 2 is concentrated on the region about the pressure medium
connection or the port P. Depending on the axial position of a
control piston (not illustrated), the operating medium passes via
the opened-up openings 2 to further openings 7 which serve for the
hydraulic connection to a working connection A or B, said working
connections being designed as an annular groove corresponding to
the pressure medium connection P.
[0024] However, if the pressure ratios are such that the spring
band 3 is acted upon in the closing direction by a pressure force
which is greater than the prevailing operating pressure, for
example due to pressure pulsations, the operating medium can flow
back via the working connections A or B, and the spring band 3 is
placed against the base of the groove 5 again and thereby closes
the openings 2 formed in the groove 5.
LIST OF REFERENCE NUMERALS
[0025] 1 Valve housing [0026] 2 Openings [0027] 3 Spring band
[0028] 4 Non-return valve [0029] 5 Groove [0030] 6 Groove [0031] 7
Openings
* * * * *