U.S. patent application number 13/124786 was filed with the patent office on 2011-11-10 for switchable component for a valve drive of an internal combustion engine.
This patent application is currently assigned to SCHAEFFLER TECHNOLOGIES GMBH & CO. KG. Invention is credited to Ulrich Elgas, Robert Heinemann, Joachim Krause, Rainer Pfeufer, Jeffrey Shewell.
Application Number | 20110271924 13/124786 |
Document ID | / |
Family ID | 41258575 |
Filed Date | 2011-11-10 |
United States Patent
Application |
20110271924 |
Kind Code |
A1 |
Heinemann; Robert ; et
al. |
November 10, 2011 |
SWITCHABLE COMPONENT FOR A VALVE DRIVE OF AN INTERNAL COMBUSTION
ENGINE
Abstract
A switchable component, which has a housing with a bore and an
inner element held in the bore with a head that projects above a
rim of the housing. The housing and the inner element are loaded
away from each other by a lost-motion spring. At least one coupling
piston sits in an opening of the inner element. Sections of the
coupling piston are moveable over a ring surface to a carrier
surface of the housing. A retaining ring packet has a circular
arc-shaped outer surface that lies in a ring groove of the bore of
the housing. A ring face of the inner element sits against the
underside of the retaining ring packet in the extended state
defining relative position. The retaining ring packet, starting
from at least one of the surfaces of the retaining ring packet has
recesses for forming tab-like sections lying circumferentially
between the recesses.
Inventors: |
Heinemann; Robert;
(Weisendorf, DE) ; Krause; Joachim;
(Obermichelbach, DE) ; Elgas; Ulrich; (Uehlfeld,
DE) ; Pfeufer; Rainer; (Hagenbuechbach, DE) ;
Shewell; Jeffrey; (Clawson, MI) |
Assignee: |
SCHAEFFLER TECHNOLOGIES GMBH &
CO. KG
DE
|
Family ID: |
41258575 |
Appl. No.: |
13/124786 |
Filed: |
October 6, 2009 |
PCT Filed: |
October 6, 2009 |
PCT NO: |
PCT/EP2009/062940 |
371 Date: |
May 27, 2011 |
Current U.S.
Class: |
123/90.52 |
Current CPC
Class: |
F01L 13/0015 20130101;
F01L 1/2405 20130101; F16B 21/183 20130101; F01L 2307/00 20200501;
F01L 1/185 20130101; F01L 2303/00 20200501; F01L 13/0005 20130101;
F01L 2001/467 20130101 |
Class at
Publication: |
123/90.52 |
International
Class: |
F01L 1/14 20060101
F01L001/14 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 18, 2008 |
DE |
10 2008 052 279.1 |
Claims
1-8. (canceled)
9. A switchable component for a valve drive of an internal
combustion engine, comprising: a housing having a bore; an inner
element, which has a cutout and an annular face, held in the bore
of the housing having a head projecting beyond an edge of the
housing; a lost motion spring, which is braced in the bore of the
housing between the housing and the inner element forcing the
housing and the inner element axially away from one another; at
least one coupling piston seated in the cutout of the inner element
and axially is moveable beyond an annular surface between the inner
element and the housing and in sections, contacting a driver
surface of the housing; and a locking ring or a locking ring pack
having an inner shell and a circular-arc-shaped outer shell resting
in an annular groove of the bore of the housing, and against an
underside of the locking ring or the locking ring pack of, the
inner element, in a deployed state, bears against the locking ring
or the locking ring pack with the annular face such that a relative
position is defined, wherein the locking ring or the locking ring
pack, proceeding from a surface of at least one of the outer shell
or the inner shell, has recesses which form lobe-like sections
situated circumferentially in between the outer shell and the inner
shell.
10. The component as claimed in claim 9, wherein the locking ring
or the locking ring pack has envelope circles and between the
envelope circles, a ring is formed which two or more annular lugs
formed with a substantially constant width.
11. The component as claimed in claim 9, wherein the locking ring
or the locking ring pack has envelope circles and between the
envelope circles, a ring which has annular lugs and a greatest
width in a section situated opposite the annular lugs with a width
that decreases, as viewed from the section in a circumferential
direction toward the annular lugs, at an inner envelope circle.
12. The component as claimed in claim 9, wherein a coupling play is
set between the locking ring or the locking ring pack and the inner
ring by the locking ring or the locking ring pack.
13. The component as claimed in claim 9, wherein when only one
locking ring is used, the locking ring can have an assortment of
thicknesses.
14. The component as claimed in claim 9, wherein when the locking
ring pack, which has two or more locking rings with lower locking
rings and uppermost locking rings, is used, the lower locking rings
have a of uniform thickness and the uppermost locking rings can
have an assortment of thicknesses.
15. The component as claimed in claim 9, wherein the inner shell of
the locking ring or the locking ring pack has a bowstring-shaped
flattening, which projects radially inward and the inner element
has a longitudinal flattening on an outer shell surface which
interacts with the bowstring-shaped flattening of the inner
shell.
16. The component as claimed in claim 9, wherein the housing has an
aperture with face wall and the locking ring or the locking ring
pack has annular lugs which are seated and bent radially outwards
in the aperture of the housing and bear with water sides against
the walls of the aperture such that the inner element is prevented
from rotating relative to the housing.
17. The component as claimed in claim 9, wherein the annular groove
in the bore of the housing is located in a region near the edge of
the housing.
18. The component as claimed in claim 9, wherein the recesses, in
conjunction with the lobe-like sections, generate a wave-like,
tooth-like or box-like profile.
19. The component as claimed in claim 9, wherein a flat or a
cylindrical counterpart surface formed on an underside of the
coupling piston, which is complementary to the driver surface.
20. The component as claimed in claim 9, wherein the cutout is a
radial bore in which two coupling pistons are situated
diametrically opposite one another.
21. The component as claimed in claim 9, wherein a flat or a
cylindrical counterpart surface formed on an underside of the
coupling piston, which is complementary to the driver surface.
22. The component as claimed in claim 9, wherein the driver surface
of the housing is a window, a bore, an annular groove, or an
annular groove segment.
Description
FIELD OF THE INVENTION
[0001] Switchable component for a valve drive of an internal
combustion engine, in particular tappet or support element, having
a housing, in the bore of which is held an inner element whose head
is situated in the region of or projects beyond an edge of the
housing, the elements being forced axially away from one another by
a lost motion spring braced between them, and at least one coupling
piston being seated in a cutout of one of the elements, which at
least one coupling piston, in an axially remote relative position
of the elements, can be moved beyond an annular surface between
said elements and in sections into a driver surface of the in each
case other element, a locking ring or a locking ring pack with a
circular-arc-shaped outer shell resting in an annular groove of the
bore of the housing, against the underside of which locking ring or
locking ring pack the inner element, in the deployed state, bears
with an annular face such that the relative position is
defined.
BACKGROUND OF THE INVENTION
[0002] Already known from the prior art are switchable components
such as roller tappets or support elements in which one locking
ring or two locking rings situated one on top of the other are
snapped into an annular groove of the housing thereof. The axially
relatively movable inner element bears with an annular step or an
annular face against an underside of said locking rings. This
serves to provide primarily a height stop for the inner element in
its deployed position, such that the at least one coupling piston
in the inner element is in alignment with the driver surface
thereof in the housing.
[0003] Furthermore, by means of locking rings provided in an
assortment of thicknesses, it is also possible to set the coupling
play (minimum required idle travel set (optimally) the same over a
wide series of similar components, which travel is covered by the
coupling means in the deployed position and, during a cam stroke,
until the driver surface thereof is directly reached). In this
regard, reference is made at this juncture to documents U.S. Pat.
No. 6,321,704 (see FIGS. 2, 3) and DE 102 04 672. Use is
conventionally made here of standardized or similar locking rings
for bores which, according to the principle of "bending beams,"
have an increasing width proceeding from the annular lugs thereof,
which width is at its greatest in a region situated opposite the
annular lugs. Said increase in width is realized at the inner shell
of the locking rings.
[0004] A disadvantage of the abovementioned embodiments is that, in
the case of a height stop against the underside of the
corresponding locking ring, on account of the increasing width
thereof, only an insufficiently large "sickle-shaped" contact
surface is available for the inner element. It has also been found
that the use of the abovementioned locking rings is problematic in
particular in the case of very small component diameters. Here,
plastic deformations or generally undesired excessive stresses may
occur in the ring material when the ring is bent together during
assembly.
OBJECT OF THE INVENTION
[0005] The invention is based on the object of providing a
component of the abovementioned type in which the stated
disadvantages are eliminated.
ACHIEVEMENT OF THE OBJECT
[0006] According to the invention, said object is achieved in that
the locking ring/locking ring pack, proceeding from at least one of
its shell surfaces [outer shell/inner shell], is formed with
recesses so as to form lobe-like portions situated
circumferentially in between.
[0007] A component is therefore provided in which the disadvantages
cited in the introduction are eliminated. The at least one locking
ring should serve primarily as a height stop for the inner element.
It is however also preferable for the one or more locking rings to
be provided in an assortment of thicknesses in the assembly
facility, such that the required coupling play can be set in the
same way by means of these.
[0008] It is also provided in a particularly expedient variant of
the invention that, by means of the at least one locking ring, the
inner element is likewise prevented from rotating relative to the
housing by means of flattenings which communicate with one
another.
[0009] On account of the proposed recesses which, in a physical
embodiment of the invention, provide the respective locking ring
with for example a wave-like or box-like profile on its
corresponding shell surface, a variant is provided which is
particularly well optimized with regard to stresses. Here, bending
stresses which occur, in particular during assembly
(bending-together and subsequent snapping into the annular groove
of the bore of the housing), are no longer distributed uniformly
over a distance according to the "bending beam" principle, but
rather are distributed between discrete zones according to the
"flexible pipe" principle. At the same time, the inner element,
when in contact with the corresponding locking ring, is provided
with an adequately large surface, such that the tilting tendency of
said inner element, or the contact pressure in said region, is
considerably reduced.
[0010] It has also been found that, when using the at least one
locking ring, the assembly forces thereof can be kept well within
limits, and plastic deformation of the locking ring in particular
in the case of very small component diameters no longer occurs.
[0011] With the integration of the proposed rotation prevention
surface, it is possible to dispense with complex separate rotation
prevention measures such as those which involve pins pressed into
the housing, or the like.
[0012] The at least one locking ring having the recesses according
to the invention may have a constant width. Said at least one
locking ring may however also be designed so as to have for example
a greatest width at its section situated opposite the annular lugs,
and a smallest (average) width in the section of the annular
lugs.
[0013] A person skilled in the art will at this juncture recognize
a multiplicity of possible designs of the shell surfaces of the
corresponding locking ring. It is of importance at this juncture
merely that the bending stress is well distributed between discrete
zones.
[0014] If, as is proposed in one refinement of the invention, a
rotation prevention means is realized by means of a flattening
which projects in radially from the inner shell of the
corresponding locking ring, then it is particularly expedient for
the annular lugs of the corresponding locking ring to project
radially outward into an aperture of the housing and to be fixed
there, by means of the outer sides thereof, on respective inner
sides of the aperture. Any occurring torque can be well absorbed in
this way.
[0015] In a further refinement of the invention, it is proposed
that the annular groove of the bore of the housing for holding the
at least one locking ring be formed directly in the region of the
edge of the housing. Assembly "from above" is made particularly
easy in this way. It is however also conceivable, and provided, for
the annular groove to be arranged at some other height section of
the bore of the housing. If appropriate, the at least one locking
ring may also run on the outer shell of the inner element and
communicate with a corresponding stop surface on the housing. Such
a design is expressly encompassed by the scope of protection of the
invention.
[0016] It is finally proposed that two diametrically opposite
coupling pistons be positioned in the radial bore of the inner
element, which coupling pistons, in the coupled state, can be moved
into a driver surface, formed for example as a window, bore,
annular groove or annular groove segment, in the housing. The
respective piston may be flattened in sections proceeding from its
radially outer face, at its "coupling side". It is however also
conceivable, and provided, for the coupling piston to be
cylindrical.
[0017] As a switchable component having the measures according to
the invention, consideration is given in particular, but not
exclusively, to a switchable support element or a switchable roller
tappet or mushroom-shaped tappet. The switchable component should
preferably be provided with a hydraulic play compensating
device.
[0018] It is therefore possible by means of the at least one
locking ring according to the invention a) to form only a height
stop, b) to realize a height stop and set a coupling play, c) to
realize a height stop and a rotation prevention means, d) to
provide only a rotation prevention means or e) to realize a height
stop and provide a rotation prevention means and at the same time
set the coupling play. Here, it is clear that the "setting the
coupling play" variant preferably encompasses the height stop.
BRIEF DESCRIPTION OF THE DRAWING
[0019] The invention will expediently be explained in more detail
on the basis of the drawing, in which:
[0020] FIG. 1 shows a component, designed as a support element, in
longitudinal section with two coupling pistons;
[0021] FIG. 2 shows the component according to FIG. 1, but rotated
by 90.degree.; and
[0022] FIGS. 3 to 8 show cross-sections through the component in
the section of the locking rings.
DETAILED DESCRIPTION OF THE DRAWING
[0023] FIGS. 1, 2 disclose a switchable component 1 designed as a
support element. Said component is composed of a pot-shaped housing
2, in the bore 3 of which an inner element 4 is held in an axially
movable manner. The latter projects with its head 5 beyond an edge
6 of the housing 2. A rocker arm may be supported at one end on
said head 5.
[0024] The inner element 4 has, in its lower section, a cutout 8
formed as a radial bore. Two radially outwardly spring-loaded
coupling pistons 9 are situated diametrically oppositely in said
cutout 8, wherein a coupled state is illustrated here. The
respective coupling piston 9 engages with its counterpart surface
29, which is formed on the underside of said coupling piston and is
flat in sections, into a driver surface 11, which is designed as a
window, in the housing 2, and said coupling piston thereby crosses
an annular surface 10 between the housing 2 and the inner element
4.
[0025] A lost motion spring 7 is installed, in a manner known per
se, between an underside of the inner element 4 and a base of the
housing 2. Said lost motion spring 7 forces the inner element 4
axially out of the housing 2.
[0026] As can also be seen from FIGS. 1, 2, the bore 3 of the
housing 2 has, close to the edge 6 thereof, an annular groove 12. A
locking ring pack 13 comprising two locking rings situated one on
top of the other runs in said annular groove. The locking ring pack
13 projects radially inward slightly beyond the annular surface 10
between the components 2, 4. The inner element 4 abuts with an
annular face 16 against an underside 15 of the locking ring pack
13. A coupling position of the coupling piston 9 as illustrated is
thereby provided. At the same time, in the case of said variant,
the coupling play is "precisely set" (see DE 102 04 672 cited in
the introduction) by means of locking rings 13 provided in an
assortment of thicknesses (lower locking rings of uniform
thicknesses, and upper locking rings in a variety of thicknesses).
Also, coupling pistons 9 may be provided in an assortment of
thicknesses as an alternative to or in combination with locking
rings 13 in an assortment of thicknesses.
[0027] As can be seen from FIG. 2, the inner element 4 has a
longitudinal flattening 21 on the outer shell 22 at a section which
intersects the edge 6 of the housing 2. A bowstring-like flattening
20 (see also FIGS. 3 to 8) which projects radially inward from the
inner shell 16a of the respective locking ring 13 communicates with
said longitudinal flattening. Annular lugs 17, 18 of the locking
ring 13, which annular lugs are situated diametrically opposite the
longitudinal flattening 21, project radially outward and project
into an aperture 23 of the housing 2 (see FIG. 4). Said annular
lugs bear with their outer sides 25, 26 against upright face walls
27, 28 of the aperture 23 and are excellent at supporting any
torque. A simply-designed means for preventing the inner element 4
from rotating relative to the housing 2 is therefore formed, and it
is possible to dispense with separate measures, as discussed in the
introductory part of the description.
[0028] The explanations below relate to the specific design of the
at least one locking ring 13. Here, the locking ring 13 has a
constant outer diameter (envelope circle A), in the style of
standardized locking rings for bores. Recesses 16b are formed on
the outer shell 14 and/or on the inner shell 16a of the locking
ring 13 so as to form lobe-like sections 16c situated
circumferentially in between. The locking ring 13 has a wave-like
profile in FIG. 3, a grooved profile in FIG. 4, a tooth-like or
box-like profile in FIGS. 5, 6, and a wave-like profile again in
FIGS. 7, 8.
[0029] On account of the design according to the invention of the
at least one locking ring 13, the bending stresses during assembly,
in particular in the case of very small bore diameters, are
considerably minimized in relation to previous solutions, and the
risk of plastic deformation of the locking ring 13 is reduced or
eliminated.
[0030] It has also been found that, on account of the measures
according to the invention, the inner element 4, when in contact by
means of its annular face 16 with an underside 15 of the locking
ring pack 13, has an excellently-designed contact surface such that
the component loading and tilting tendency of the inner element 4
are reduced.
TABLE-US-00001 List of Reference Numerals and Symbols 1 Component 2
Housing 3 Bore 4 Inner Element 5 Head 6 Edge 7 Lost Motion Spring 8
Cutout 9 Coupling Piston 10 Annular Surface 11 Driver Surface 12
Annular Groove 13 Locking Ring, Locking Ring Pack 14 Outer Shell 15
Underside 16 Annular Face 16a) Inner Shell 16b) Recess 16c) Section
17 Annular Lug 18 Annular Lug 19 Section 20 Flattening 21
Longitudinal Flattening 22 Outer Shell Surface 23 Aperture 24 Not
Assigned 25 Outer Side 26 Outer Side 27 Face Wall 28 Face Wall 29
Counterpart Surface A Envelope Circle B Envelope Circle
* * * * *