U.S. patent application number 13/780889 was filed with the patent office on 2013-08-29 for rocker arm.
This patent application is currently assigned to SCHAEFFLER TECHNOLOGIES AG & CO. KG. The applicant listed for this patent is Schaeffler Technologies AG & Co. KG. Invention is credited to Michael Kress, Oliver Witter.
Application Number | 20130220254 13/780889 |
Document ID | / |
Family ID | 48950832 |
Filed Date | 2013-08-29 |
United States Patent
Application |
20130220254 |
Kind Code |
A1 |
Witter; Oliver ; et
al. |
August 29, 2013 |
ROCKER ARM
Abstract
Rocker arm for actuating at least one gas exchange valve of an
internal combustion engine having an elongated lever body (2) with
a floor (3) and with side walls (4,5) angled away therefrom,
wherein a first end section (6) of the lever body (2) has a cup (9)
for a support element formed in the floor (3), and in that a
section (7) near the center is provided with a cam engagement
surface and in that a second end section (8) of the lever body (2)
has a contact surface (12) for a valve stem end of the gas exchange
valve, wherein a crossbar (13) extends between the section (7) near
the center and the second end section (8), wherein the crossbar
(13) has a stamping 14) that is provided on the side facing away
from the section (7) near the center.
Inventors: |
Witter; Oliver; (Westhausen,
DE) ; Kress; Michael; (Lonnerstadt, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Schaeffler Technologies AG & Co. KG; |
|
|
US |
|
|
Assignee: |
SCHAEFFLER TECHNOLOGIES AG &
CO. KG
Herzogenaurach
DE
|
Family ID: |
48950832 |
Appl. No.: |
13/780889 |
Filed: |
February 28, 2013 |
Current U.S.
Class: |
123/90.44 |
Current CPC
Class: |
B21K 1/205 20130101;
F01L 1/185 20130101; F01L 1/182 20130101 |
Class at
Publication: |
123/90.44 |
International
Class: |
F01L 1/18 20060101
F01L001/18 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 29, 2012 |
DE |
102012203107.3 |
Claims
1. Rocker arm for actuating at least one gas exchange valve of an
internal combustion engine having an elongated lever body (2) with
a floor (3) and with side walls (4,5) angled away therefrom,
wherein a first end section (6) of the lever body (2) has a cup (9)
for a support element formed in the floor (3), and in that a
section (7) near the center is provided with a cam engagement
surface and in that a second end section (8) of the lever body (2)
has a contact surface (12) for a valve stem end of the gas exchange
valve, wherein a crossbar (13) extends between the section (7) near
the center and the second end section (8), characterized in that
the crossbar (13) has a stamping (14) that is provided on the side
facing away from the section near the center (7).
2. Rocker arm according to claim 1, wherein a shape of the stamping
(14) is matched to the valve stem end.
3. Rocker arm according to one of the preceding claims, wherein the
second end section (8) of the lever body (2) has a W-shaped profile
when viewed in cross-section.
4. Rocker arm according to one of the preceding claims, wherein a
distance (L1) between a longitudinal center (15) of the cup (9) and
a center of rotation (17) of the cam pickup surface is half as
large as or less than half a distance (L2) between the longitudinal
center (15) of the cup (9) and a center of a contact region (18) of
the gas exchange valve at the contact surface (12).
5. Rocker arm according to one of the preceding claims, wherein the
cam pickup surface is implemented by a cam roller, and wherein the
section near the center has a recess (11) in the floor that serves
to accommodate the cam roller.
6. Rocker arm according to one of the preceding claims, wherein the
lever body (2) is either produced by stamping and forming
techniques from a sheet metal material, or by extrusion molding.
Description
FIELD OF THE INVENTION
[0001] The invention concerns a rocker arm for actuating a gas
exchange valve of an internal combustion engine.
BACKGROUND OF THE INVENTION
[0002] In internal combustion engines, rocker arms are located in a
valve train as transmission elements between cams and the gas
exchange valves to be actuated. Rocker arms consist of a lever body
that is supported at one of its ends on a support element and with
its other end engages, through a contact surface, the gas exchange
valve to be opened. In a section of the lever body near the center,
a cam pickup surface is provided on which a cam of a camshaft runs
during operation of an internal combustion engine, causing a
pivoting motion of the rocker arm. The cam pickup surface can be
implemented as a sliding surface or as a cam roller.
[0003] A rocker arm for actuating a gas exchange valve of an
internal combustion engine is known from DE 10 2008 029,333 A1. At
one end, the rocker arm has an oval opening that encompasses a
valve stem end of the gas exchange valve. In addition, the rocker
arm provides a cam roller in a section near the center.
[0004] WO2011/157499 A1 discloses a rocker arm that has a cam
roller supported on an axle pin by means of a needle roller and
cage assembly. A contact surface for a valve stem end of the gas
exchange valve is provided at one end of the rocker arm. Side bars
are provided in the region of the contact surface to guide the
rocker arm on the valve stem end.
SUMMARY OF THE INVENTION
[0005] The object of the present invention is to provide a rocker
arm that can be manufactured economically and that ensures adequate
stiffness.
[0006] According to the invention this object is attained by a
rocker arm for actuating at least one gas exchange valve of an
internal combustion engine having an elongated lever body with a
floor and with side walls angled away therefrom, wherein a first
end section of the lever body has a cup for a support element
formed in the floor, and in that a section near the center is
provided with a cam engagement surface and in that a second end
section of the lever body has a contact surface for a valve stem
end of the gas exchange valve, wherein a crossbar extends between
the section near the center and the second end section and wherein
the crossbar has a stamping that is provided on the side facing
away from the section near the center.
[0007] In the rocker arm according to the invention, the crossbar
is provided with a stamping. The stamping can be an embossing, for
example. The stamping in the crossbar makes it possible to avoid
contact between the valve stem end and the lever body during
pivoting motions of the rocker arm. The necessary stiffening of the
rocker arm is ensured by the crossbar, which in turn results in
increased strength of the rocker arm.
[0008] In a preferred embodiment of the invention, the shape of the
stamping is matched to the valve stem end. This means that the
shape of the stamping is designed to be complementary to the shape
of the valve stem end. Preferably the stamping is implemented as a
cylindrical molding.
[0009] Preferably the second end section of the lever body has a
W-shaped profile when viewed in cross-section. As a result of the
W-shaped profile, the side bars known from the prior art that would
be necessary for valve guidance are eliminated. This has the
advantage that the weight of material used can be reduced, and thus
the production costs can be decreased. The W-shaped profile
preferably is open in the direction facing away from the gas
exchange valve. However, a reversed arrangement of the W-shaped
profile is also possible.
[0010] In another embodiment of the invention, a distance between a
longitudinal center of the cup and a center of rotation of the cam
pickup surface is half as large as or less than half a distance
between the longitudinal center of the cup and a center of a
contact region of the gas exchange valve at the contact surface.
Accordingly, the cam pickup surface can be positioned close to the
contact region of the gas exchange valve. This has the advantage
that the overall length of the rocker arm can be shortened to
achieve a compact component.
[0011] In one embodiment, the cam pickup surface is implemented by
a cam roller, and the section near the center has a recess in the
floor that serves to accommodate the cam roller. The recess in the
floor creates the necessary free space for the cam roller so that
rotary motion of the cam roller is possible.
[0012] Preferably, the lever body is either produced by stamping
and forming techniques from a sheet metal material, or by extrusion
molding. However, other materials and manufacturing methods are
also possible.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] An exemplary embodiment of the invention is explained below
using three figures.
[0014] They show:
[0015] FIG. 1 a rocker arm according to the invention in a
perspective view,
[0016] FIG. 2 a bottom view of the rocker arm according to the
invention, and
[0017] FIG. 3 a longitudinal cross-section through the rocker arm
according to the invention.
DETAILED DESCRIPTION OF THE DRAWINGS
[0018] FIGS. 1 and 2 each show different views of a rocker arm 1
according to the invention. The rocker arm 1 has an elongated lever
body 2, which has a floor 3 and side walls 4, 5 angled away
therefrom. The floor 3 and the side walls 4, 5 form a W-shaped
profile when viewed in cross-section. Moreover, the lever body 2,
which is made of a sheet metal material, is divided into a first
end section 6, a section 7 near the center, and a second end
section 8.
[0019] Formed in the part of the floor 3 running along the first
end section 6 is a cup 9, which rises between the side walls 4, 5.
The cup 9 provides support on a support element that is not
shown.
[0020] In the region of the section 7 near the center, each of the
side walls 4,5 has a bore 10 serving to support a cam roller that
is not shown. The cam roller that is not shown defines a cam pickup
surface. A recess 11 designed with a rectangular outer contour is
provided in the part of the floor 3 running along the section 7
near the center.
[0021] A contact surface 12 for a valve stem end, not shown, of a
gas exchange valve is provided on the part of the floor 3 running
along the second end section 8 of the lever body 2. A crossbar 13
that is provided between the side walls 4,5 extends between the
second end section 8 and the section 7 near the center. The
crossbar 13 has a stamping 14, which is implemented as a
cylindrical molding, on the side facing away from the section 7
near the center. The stamping 14 makes it possible for adequate
clearance of the contact surface relative to the gas exchange
valve, not shown, to be present during pivoting motions of the
rocker arm 1.
[0022] FIG. 3 shows a longitudinal cross-section through the rocker
arm 1 according to the invention. This illustrates the relationship
of the individual sections to one another. In the first end section
6, the cup 9 has a longitudinal center 15. Each of the bores 10 has
a center point 16 that defines a center of rotation 17 for the cam
pickup surface. The contact surface 12 defines a contact region 18
of the gas exchange valve, not shown.
[0023] A distance L1 is defined between the longitudinal center 15
of the cup 9 and the center of rotation 17 of the cam pickup
surface. A distance L2 is defined between the longitudinal center
15 of the cup 9 and a center of the contact region 18 of the gas
exchange valve. The distance L1 here is half as large as or less
than half the distance L2. This distance ratio makes possible a
short, compact lever body 2.
LIST OF REFERENCE CHARACTERS
[0024] 1 rocker arm [0025] 2 lever body [0026] 3 floor [0027] 4
side wall [0028] 5 side wall [0029] 6 first end section [0030] 7
section near the center [0031] 8 second end section [0032] 9 cup
[0033] 10 bore [0034] 11 recess [0035] 12 contact surface [0036] 13
crossbar [0037] 14 stamping [0038] 15 longitudinal center of the
cup [0039] 16 center point [0040] 17 center of rotation [0041] 18
contact region of the gas exchange valve [0042] L1 distance [0043]
L2 distance
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