U.S. patent application number 12/593628 was filed with the patent office on 2011-01-06 for control valve.
This patent application is currently assigned to SCHAEFFLER KG. Invention is credited to Jens Hoppe, Andreas Roehr.
Application Number | 20110000447 12/593628 |
Document ID | / |
Family ID | 39414930 |
Filed Date | 2011-01-06 |
United States Patent
Application |
20110000447 |
Kind Code |
A1 |
Hoppe; Jens ; et
al. |
January 6, 2011 |
CONTROL VALVE
Abstract
A control valve, particularly for a device for altering the
actuation periods of an internal combustion engine, which has a
valve housing that is configured with a substantially hollow
cylindrical structure, a control piston disposed inside the valve
housing and is axially displaceable therein, and a closing element.
The control piston has at least one section with a hollow structure
that ends in an opening of the control piston and the closing
element is disposed in the opening.
Inventors: |
Hoppe; Jens; (Erlangen,
DE) ; Roehr; Andreas; (Heroldsbach, DE) |
Correspondence
Address: |
LUCAS & MERCANTI, LLP
475 PARK AVENUE SOUTH, 15TH FLOOR
NEW YORK
NY
10016
US
|
Assignee: |
SCHAEFFLER KG
HERZOGENAURACH
DE
|
Family ID: |
39414930 |
Appl. No.: |
12/593628 |
Filed: |
February 14, 2008 |
PCT Filed: |
February 14, 2008 |
PCT NO: |
PCT/EP08/51775 |
371 Date: |
September 29, 2009 |
Current U.S.
Class: |
123/90.15 |
Current CPC
Class: |
F16K 11/0716 20130101;
F16K 11/07 20130101; F01L 1/3442 20130101; F01L 2001/34426
20130101 |
Class at
Publication: |
123/90.15 |
International
Class: |
F01L 1/34 20060101
F01L001/34 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 30, 2007 |
DE |
10 2007 015 333.5 |
Claims
1. A control valve for a device for varying the control times of an
internal combustion engine, comprising: an essentially
hollow-cylindrically designed valve housing; an axially
displaceable control piston arranged inside the valve housing; and
a closing element, the control piston having at least one portion
of hollow design which issues into an orifice of the control
piston, and the closing element being arranged in the orifice,
wherein the closing element has a circumferential wall which is
adapted essentially to an inner surface area of the control piston
in a region of the orifice, the circumferential wall having at
least one material receptacle of smaller outside diameter, the
material receptacle being followed in an axial direction of the
closing element by a region of larger outside diameter on a side
facing away from the orifice, and the inner surface area of the
control piston engaging into the material receptacle.
2. The control valve of claim 1, wherein the material receptacle an
annular groove proceeding in a circumferential direction of the
closing element.
3. The control valve of claim 1, wherein the material receptacle is
a pocket.
4. The control valve of claim 1, wherein the material receptacle is
a chamfer of a circumferential edge of an axial sidewall of the
closing element.
5. The control valve of claim 1, wherein the outside diameter of
the control piston is made smaller in the region of the material
receptacle than a maximum outside diameter of the control
piston.
6. The control valve of claim 1, wherein the closing element is
connected to the control piston by means of a materially integral
connection, an adhesive bond, a soldered joint or a welded
joint.
7. A control valve for a device for varying control times of an
internal combustion engine, comprising: an essentially
hollow-cylindrically designed valve housing; an axially
displaceable control piston arranged inside the valve housing; and
a closing element, the control piston having at least one portion
of hollow design which issues into an orifice of the control
piston, and the closing element being arranged in the orifice,
wherein the closing element is connected to the control piston by
means of a materially integral connection, an adhesive bond, a
soldered joint or a welded joint.
8. A method for producing a control valve for a device for varying
control times of an internal combustion engine, comprising: an
essentially hollow-cylindrically designed valve housing; an axially
displaceable control piston arranged inside the valve housing; and
a closing element, the control piston having at least one portion
of hollow design which issues into an orifice of the control
piston, having the following steps: positioning of the closing
element inside the orifice of the control piston, and displacement
of material of the control piston radially inward in the region of
the closing element.
9. The method of claim 8, wherein the material of the control
piston is displaced radially inward by means of radial embossing,
radial circumferential calking or radial segmental calking of the
control piston.
10. The method of claim 8, wherein the material of the control
piston is displaced radially inward by means of axial embossing,
axial annular calking or axial segmental calking of an axial side
face of the control piston.
11. The method of claim 8, wherein the material is displaced into
at least one material receptacle formed on a circumferential face
of the closing element.
Description
FIELD OF THE INVENTION
[0001] The invention relates to a control valve, in particular for
a device for varying the control times of an internal combustion
engine, with an essentially hollow-cylindrically designed valve
housing, an axially displaceable control piston arranged inside the
valve housing, and a closing element, the control piston having at
least one portion of hollow design which issues into an orifice of
the control piston, and the closing element being arranged in the
orifice.
[0002] The invention relates, further, to a method for producing a
control valve, in particular for a device for varying the control
times of an internal combustion engine, with an essentially
hollow-cylindrically designed valve housing, an axially
displaceable control piston arranged inside the valve housing, and
a closing element, the control piston having at least one portion
of hollow design which issues into an orifice of the control
piston.
[0003] Control valves of this type are used in order to control
pressure medium streams in hydraulic devices, for example hydraulic
devices for varying the control times of an internal combustion
engine (camshaft adjusters).
[0004] A control valve of this type and a camshaft adjuster are
known, for example, from DE 10 2004 038 252 A1. The camshaft
adjuster has two components rotatable in relation to one another
and two pressure chambers acting counter to one another, the
relative phase of the two components being capable of being
selectively varied or changed by the pressure chambers being loaded
with or relieved of pressure in a directed manner.
[0005] The control of the pressure medium streams to and from the
pressure chambers takes place by means of a control valve, in this
case a 4/3-way proportional valve. Other types of directional
valves may also be envisaged, however, in particular with different
numbers of connections and/or control positions.
[0006] The control valve consists essentially of an electromagnetic
actuating drive, of a hollow-cylindrically designed valve housing
and of a likewise essentially hollow-cylindrically designed axially
displaceable control piston arranged inside the valve housing. The
valve housing is provided in each case with a connection for the
pressure chambers (working connection), with a connection to the
pressure medium pump and with at least one connection to a
tank.
[0007] The control piston can be brought axially into any position
between two defined end positions, counter to the spring force of a
spring element, by means of an electromagnetic actuating member.
The control piston is provided, furthermore, with annular grooves
and control edges, with the result that the individual pressure
chambers can be connected selectively to the pressure medium pump
or to the tank. A position of the control piston may likewise be
provided in which the pressure medium chambers are separated both
from the pressure medium pump and from the pressure medium
tank.
[0008] The control piston can be displaced into any desired
position inside the valve housing by means of the actuating drive
which acts counter to a spring element. For this purpose, an axial
orifice of the control piston, which stands opposite the actuating
drive, is closed, tight to pressure medium, by means of a closing
element. A tappet rod movable linearly by the actuating drive, acts
on this closing element. The closing element is connected to the
control piston by means of a nonpositive connection, for example by
the closing element being pressed with oversize into the orifice of
the control piston.
[0009] In modern internal combustion engines, high alternating
moments act upon the camshafts on account of the opening and
closing movement of the gas exchange valves counter to the force of
a valve spring. These alternating moments generate in the camshaft
adjusters pressure peaks which may exceed 100 bar. These pressure
peaks are transmitted to the control valve via the hydraulic
system. There may then be the risk that, in the presence of high
alternating moments and therefore high pressure peaks, the axial
securing of the closing element in relation to the control piston
is canceled and, for example, the closing element creeps out of the
orifice.
[0010] The result of this, on the one hand, may be that the full
valve stroke of the control valve can no longer be utilized, the
consequence of this being that the performance, in particular the
adjustment speed, that camshaft adjusters is significantly
impaired.
[0011] On the other hand, the cancellation of the fixed axial
relation of the closing element to the control piston leads to a
situation where, in a specific position of the tappet rod, the
expected position of the control piston in relation to the valve
housing is not identical to the actual position, with the result
that the regulation of the camshaft adjuster is seriously
disrupted.
SUMMARY OF THE INVENTION
[0012] The object on which the invention is based, therefore, is to
avoid these outlined disadvantages and therefore to provide a
hydraulic control valve, in which, in particular, a deterioration
in the performance and regulating accuracy of the control valve
during operation is to be prevented.
[0013] In a first embodiment, this object is achieved, according to
the invention, in that the closing element has a circumferential
wall which is adapted essentially to an inner surface area of the
control piston in the region of the orifice, the circumferential
wall having at least one material receptacle of smaller outside
diameter, the material receptacle being followed in the axial
direction of the closing element by a region of larger outside
diameter on the side facing away from the orifice, and the inner
surface area of the control piston engaging into the material
receptacle.
[0014] In this case, there may be provision for the material
receptacle to be designed as an annular groove proceeding in the
circumferential direction of the closing element. Alternatively,
the material receptacle may be designed as a pocket. Embodiments
may likewise be envisaged in which the material receptacle is
designed as a chamfer of a circumferential edge of an axial
sidewall of the closing element.
[0015] In a development of the invention, there is provision for
the outside diameter of the control piston to be made smaller in
the region of the material receptacle than a maximum outside
diameter of the control piston.
[0016] In addition, there may be provision for connecting the
closing element (37b) to the control piston (37) by means of a
materially integral connection, an adhesive bond, a soldered joint
or a welded joint.
[0017] In a further embodiment, the object is achieved, according
to the invention, in that the closing element is connected to the
control piston by means of a materially integral connection, an
adhesive bond, a soldered joint or a welded joint.
[0018] The object is by means of a method according to the
invention having the following steps: [0019] positioning of the
closing element inside the orifice of the control piston, [0020]
displacement of material of the control piston radially inward in
the region of the closing element, [0021] solved.
[0022] In this case, there may be provision for the material of the
control piston to be displaced radially inward by means of radial
embossing, radial circumferential calking or radial segmental
calking of the control piston.
[0023] Alternatively, there may be provision for the material of
the control piston to be displaced radially inward by means of
axial embossing, axial annular calking or axial segmental calking
of an axial side face of the control piston.
[0024] In a development of the method according to the invention,
there may be provision for the material to be displaced into at
least one material receptacle formed on a circumferential face of
the closing element.
[0025] In a control valve of this type, a control piston is
arranged axially displaceably inside an essentially
hollow-cylindrically designed valve housing. The control piston is
of hollow design at least in one portion, this portion ending in an
orifice of the control piston. In this case, there may be provision
for the orifice to be formed on an axial side face of the control
piston.
[0026] In addition to this orifice, further orifices, in particular
radial bores, may be provided, via which the portion of hollow
design of the control piston communicates, for example, with a
pressure medium pump or with working connections or, via these,
with a consumer.
[0027] The control piston may, for example, be designed as an
essentially hollow-cylindrical structural element or may have a
U-shaped design in longitudinal section.
[0028] A closing element is arranged inside the orifice. The
closing element may, for example, be of cylindrical or pot-shaped
design and serve, for example, for closing the orifice tight to
pressure medium. Furthermore, there may be provision for the
closing element to serve as a bearing element for a tappet rod, via
which an actuating movement of an actuating member can be
transmitted to the control piston.
[0029] In this case, there is provision for the radially outer
circumferential wall of the closing element to be adapted to an
inner surface area of the control piston in the region of the
orifice.
[0030] In order to increase the press-out forces of the closing
element, there may be provision, on the one hand, for making a
nonpositive connection between the closing element and the control
element. This may be implemented, for example, by pressing the
closing element designed with oversize into the orifice. In order
to increase the nonpositive connection, there may be provision for
displacing material of the control piston radially inward after the
positioning of the closing element inside the orifice. This may be
implemented, for example, by means of the radial embossing, radial
circumferential calking or radial segmental calking or by means of
the axial embossing, axial annular calking or axial segmental
calking of an axial side face of the control piston radially
inward.
[0031] Additionally or alternatively to this, there may be
provision for the circumferential wall of the closing element to
have at least one material receptacle of smaller outside diameter,
the inner surface area of the control piston engaging into the
material receptacle. In this case, the material receptacle may be
followed in the axial direction by a region of the closing element,
the outside diameter of which is designed to be larger than the
outside diameter in the region of the material receptacle. Thus, a
positive connection is achieved, and the closing element is
effectively prevented from creeping. In the event that the material
receptacle is followed by the region of enlarged diameter on the
side facing away from the orifice, this prevents the closing
element from creeping out of the control piston. With an opposite
configuration, a creeping of the closing element into the control
piston, for example due to the action of force by a tappet rod
acting on the closing element, can be prevented. It is likewise
conceivable that the material receptacle is followed on both sides
by regions of enlarged diameter, with the result that the closing
element is secured in position by means of a positive
connection.
[0032] Additionally or alternatively to the abovementioned
solutions, a materially integral connection, an adhesive bond, a
soldered joint or a welded joint may be provided between the
closing element and the control piston.
[0033] While the material displacement is being carried out on the
control piston, material build-ups may occur on the outer surface
area of the control piston due to the engagement of tools. These
build-ups, if they project beyond the maximum outside diameter of
the control piston, may lead to a jamming of the control piston
inside the valve housing. This is effectively counteracted by the
control piston being designed in the region of the material
receptacle with a smaller outside diameter than the maximum outside
diameter of the control piston. Furthermore, the annular wall
portion generated thereby at the interface between the regions of
different outside diameter may be utilized as a stop for the
material displacement tool.
[0034] The material displacements may take place along the entire
circumference of the control piston or only segmentally.
BRIEF DESCRIPTION OF THE DRAWINGS
[0035] Further features of the invention may be gathered from the
following description and from the drawings which illustrate
exemplary embodiments of the invention in a simplified form and in
which:
[0036] FIG. 1 shows a longitudinal section through a device for
varying the control times of an internal combustion engine,
together with a pressure medium circuit;
[0037] FIG. 2 shows a cross section through the device illustrated
in FIG. 1;
[0038] FIG. 3 shows a longitudinal section through a control valve
according to the invention;
[0039] FIG. 4a shows a longitudinal section through a first
embodiment of a control piston of a control valve according to the
invention;
[0040] FIG. 4b shows a perspective view of the control piston from
FIG. 4a;
[0041] FIG. 5a shows a cross section through a second embodiment of
a control piston of a control valve according to the invention;
and
[0042] FIG. 5b shows a longitudinal section through the control
piston from FIG. 5a along the line A-A.
DETAILED DESCRIPTION OF THE DRAWING
[0043] FIGS. 1 and 2 show a device 1 for varying the control times
of an internal combustion engine. The device 1 consists essentially
of a stator 2 and of a rotor 3 arranged concentrically thereto. A
drive wheel 4 is connected fixedly in terms of rotation to the
stator 2 and, in the embodiment illustrated, is designed as a chain
wheel. The stator 2 is mounted rotatably on the rotor 3, in the
embodiment illustrated five recesses 5 spaced apart in the
circumferential direction being provided on the inner surface area
of the stator 2. The recesses 5 are delimited in the radial
direction by the stator 2 and the rotor 3, in the circumferential
direction by two sidewalls 6 of the stator 2 and in the axial
direction by a first and a second side cover 7, 8. Each of the
recesses 5 is closed, pressure-tight, in this way.
[0044] Vane grooves 10 proceeding axially are formed on the outer
surface area of the rotor 3, a radially extending vane 11 being
arranged in each vane groove 10. A vane 11 extends into each recess
5, the vanes 11 bearing in the radial direction against the stator
2 and in the axial direction against the side covers 7, 8. Each
vane 11 subdivides a recess 5 into two pressure chambers 12, 13
acting counter to one another.
[0045] By means of first and second pressure medium lines 16, 17,
the first and second pressure chambers 12, 13 can be connected via
a control valve 18 to a pressure medium pump 19 or to a tank 20. An
actuating drive is thereby formed which allows a relative rotation
of the stator 2 with respect to the rotor 3. When the first
pressure chambers 12 are connected to the pressure medium pump 19
and the second pressure chambers 13 to the tank 20, the first
pressure chambers 12 expand at the expense of the second pressure
chambers 13. This results in a displacement of the vanes 11 in a
circumferential direction, in the direction illustrated by the
arrow 21. As a result of the displacement of the vanes 11, the
rotor 3 is rotated with respect to the stator 2.
[0046] The relative rotation of the rotor 3 with respect to the
stator 2 results in a phase displacement between the camshaft and
crankshaft as a consequence of the supply or discharge of pressure
medium to or from the pressure chambers 12, 13. By pressure medium
being introduced into or discharged from the pressure chambers 12,
13 in a directed manner, the control times of the gas exchange
valves of the internal combustion engine can thus be varied or
selectively held in a directed way.
[0047] In the embodiment illustrated, the pressure medium lines 16,
17 are designed as essentially radially arranged bores which extend
from a central bore 22 of the rotor 3 to the outer surface area of
the latter. Inside the central bore 22, a central valve, not
illustrated, may be arranged, via which the pressure chambers 12,
13 can be connected to the pressure medium pump 19 or to the tank
20 in a directed manner. A further possibility is to arrange inside
the central bore 22 a pressure medium distributor which connects
the pressure medium lines 16, 17 to the connections of an
externally mounted control valve 18 via pressure medium ducts and
annular grooves.
[0048] FIG. 3 illustrates a control valve 18 according to the
invention in longitudinal section. An essentially
hollow-cylindrically designed valve housing 34 is designed with a
radial pressure medium connection P, with a radial tank connection
T.sub.1, with two working connections A, B and with an axial tank
connection T.sub.2. The radial connections P, T.sub.1, A, B are
designed as first annular grooves 35 which are spaced axially apart
from one another and which are formed on the outer surface area of
the valve housing 34. The first annular grooves 35 are provided
with a plurality of first bores 36 which issue into the interior of
the valve housing 34.
[0049] A likewise essentially hollow-cylindrically designed control
piston 37 is arranged axially displaceably inside the valve housing
34. One axial end of the control piston 37 is delimited,
pressure-tight, by means of a wall portion 37a. A closing element
39 is arranged in an orifice 37b, lying opposite the wall portion
37a, of the control piston 37. The closing element 39 is designed
in such a way that it closes the orifice 37b pressure-tight.
[0050] By means of an actuating member 32, the control piston 37
can be brought into and held in any desired position within two
extreme values, counter to the spring force of a spring element 33,
by means of a tappet rod 32a. For this purpose, the tappet rod 32a
of the actuating member 32 bears against the closing element 39.
Linear actuating movements of the actuating member 32 are thus
transmitted via the tappet rod 32a to the closing element 39 and
therefore to the control piston 37.
[0051] The outer surface area of the control piston 37 is provided
with three axially spaced-apart second annular grooves 38. The two
outer annular grooves 38 communicate via second bores 41 with the
interior of the control piston 37. Via the annular grooves 38, the
second bores 41 and the interior of the control piston 37, pressure
medium can be conducted from the pressure medium connection P to
the first or second working connections A, B as a function of the
position of the control piston 37 inside the valve housing 34, the
interior of the control piston 37 being connected to the pressure
medium connection P in any position. Likewise, in the case of
specific positions of the control piston 37 in relation to the
valve housing 34, pressure medium can pass from the second working
connection B via the middle annular groove 38 to the radial tank
connection T.sub.1 and from the first working connection A to the
axial tank connection T.sub.2.
[0052] Thus, by the position of the control piston 37 inside the
valve housing 34 being influenced in a directed manner, pressure
medium can be conducted to specific pressure chambers 12, 13 and be
discharged from the other pressure chambers 12, 13, thus leading to
a relative change in the phase position between the rotor 3 and
stator 2 and, consequently, between the crankshaft and
camshaft.
[0053] Due to the pressure prevailing inside the control piston 37,
there may be the risk that the closing element 39 creeps in the
axial direction. This risk is due, above all, to the alternating
moments acting on the camshaft and caused by the gas exchange valve
springs, with the result that pressures above 100 bar may be
induced in the hydraulic system. In order to prevent the closing
element 39 from creeping, in the embodiments according to the
invention of a control valve 18, the connection between the control
piston 37 and the closing element 39 is to be strengthened. This
may be achieved, for example, by means of a positive and/or
materially integral connection and/or a strengthening of the
nonpositive connection. Adhesive bonds or combinations of these
types of connection may likewise be envisaged.
[0054] FIGS. 4a and 4b show a first embodiment according to the
invention of a control piston 37.
[0055] In this embodiment, the closing element 39 is of pot-shaped
design, a cylindrical circumferential wall 39a of the closing
element 39 coming to bear against the inner surface area 37d of the
orifice 37b. After the operation of pressing the closing element 39
into the orifice 37b of the control piston 37, material 37c of the
control piston 37 is displaced radially inward in the region of the
cylindrical circumferential wall 39a. This may take place, for
example, by means of radial embossing or calking. In this case, the
material displacement may take place along the entire circumference
of the control piston 37 in the form of an annular groove or
segmentally, as illustrated in the embodiment. This leads to a
reinforcement of the nonpositive connection between the control
piston 37 and closing element 39.
[0056] Additionally, so that the flowing material can be received
on the inner surface area 37d of the control piston 37, there may
be provision for forming on the closing element 39 one or more
material receptacles 40, for example circumferential grooves or
pockets, into which the material 37c can be displaced. This gives
rise to a positive connection between the control piston 37 and the
closing element 39, with the result that the press-out forces are
increased significantly.
[0057] During the material displacement operation, the outside
diameter of the control piston 37 may become slightly larger at the
margins of the pressure-loaded region. In order to prevent this
enlargement in diameter from leading to a jamming of the control
piston 37 inside the valve housing 34, there is provision for
making the outside diameter of the control piston 37 smaller in the
region of the material displacement than the maximum outside
diameter of the control piston 37, in particular smaller than the
inside diameter of the valve housing 34.
[0058] FIGS. 5a and 5b show a second embodiment according to the
invention of a control piston 37. In this exemplary embodiment,
too, after the closing element 39 has been positioned inside the
control piston 37, for example by means of an operation to press
the closing element 39 with oversize into the orifice 37b of the
control piston 37, material 37c of the control piston 37 is
displaced radially inward. In contrast to the first embodiment,
this takes place by axial embossing by means of annular or
segmental calking. In this case, the tool is pressed into the axial
side face (annular wall 37e) of the control piston 37. As a result,
the nonpositive connection between the closing element 39 and the
control piston 37 is increased, and a positive connection occurs in
the creeping direction, and therefore the relative position of the
closing element 39 with respect to the control piston 37 is
secured.
[0059] In order to absorb the material build-up which occurs,
material receptacles 40 may be provided here, too. In the exemplary
embodiment, the material receptacle 40 is implemented by means of a
suitably dimensioned phase 40a or a suitably dimensioned radius of
the orifice-side bottom of the closing element 39. In this case,
both the chamfer 40a and the material displacement may extend over
the entire outer circumference of the bottom or may be formed only
segmentally.
[0060] Alternatively to the pot-shaped embodiment of the closing
element 39, as illustrated, other embodiments, for example a
cylindrical closing element 39, may be provided.
[0061] Alternatively, there may be provision for connecting the
closing element 39 to the control piston 37 by means of an adhesive
bond or a soldered or welded joint. Combinations of the first and
the second embodiment with an adhesive bond or soldered or welded
joint may likewise be envisaged.
REFERENCE SYMBOLS
[0062] 1 Device [0063] 2 Stator [0064] 3 Rotor [0065] 4 Drive wheel
[0066] 5 Recesses [0067] 6 Sidewall [0068] 7 First side cover
[0069] 8 Second side cover [0070] 10 Vane groove [0071] 11 Vane
[0072] 12 First pressure chamber [0073] 13 Second pressure chamber
[0074] 16 First pressure medium line [0075] 17 Second pressure
medium line [0076] 18 Control valve [0077] 19 Pressure medium pump
[0078] 20 Tank [0079] 21 Arrow [0080] 22 Central bore [0081] 31
Pressure medium circuit [0082] 32 Actuating member [0083] 32a
Tappet rod [0084] 33 Spring element [0085] 34 Valve housing [0086]
35 First annular groove [0087] 36 First bores [0088] 37 Control
piston [0089] 37a Wall portion [0090] 37b Orifice [0091] 37c
Material [0092] 37d Inner surface area [0093] 37e Annular wall
[0094] 38 Second annular groove [0095] 39 Closing element [0096]
39a Circumferential wall [0097] 40 Material receptacle [0098] 40a
Chamfer [0099] 41 Second bore [0100] P Pressure medium connection
[0101] T.sub.1 Radial tank connection [0102] T.sub.2 Axial tank
connection [0103] A First working connection
* * * * *