U.S. patent application number 12/744142 was filed with the patent office on 2010-09-30 for modular construction camshaft adjuster with a chain or belt wheel.
This patent application is currently assigned to SCHAEFFLER TECHNOLOGIES GMBH & CO. KG. Invention is credited to Joachim Dietz, Andreas Strauss.
Application Number | 20100242876 12/744142 |
Document ID | / |
Family ID | 40566274 |
Filed Date | 2010-09-30 |
United States Patent
Application |
20100242876 |
Kind Code |
A1 |
Dietz; Joachim ; et
al. |
September 30, 2010 |
MODULAR CONSTRUCTION CAMSHAFT ADJUSTER WITH A CHAIN OR BELT
WHEEL
Abstract
A modular construction camshaft adjuster for the camshaft drive
of an internal combustion engine with a chain or belt wheel, which
has at least one wheel rim facing radially outwards with tooth
engagement recesses, an annular wheel plate around a central
circular opening and an essentially cylindrical wheel wall with a
wall thickness, projecting in an axial direction from the annular
wheel plate, such that the wheel wall and the wheel plate together
form a cup shape. The minimum wall thickness of the essentially
cylindrical wheel wall beneath the at least one wheel is equal to
half the tooth engagement recess and the cup-shaped chain or belt
wheel is made from a lightweight material.
Inventors: |
Dietz; Joachim; (Frensdorf,
DE) ; Strauss; Andreas; (Forchheim, DE) |
Correspondence
Address: |
LUCAS & MERCANTI, LLP
475 Park Avenue South
New York
NY
10016
US
|
Assignee: |
SCHAEFFLER TECHNOLOGIES GMBH &
CO. KG
Herzogenaurach
DE
|
Family ID: |
40566274 |
Appl. No.: |
12/744142 |
Filed: |
November 4, 2008 |
PCT Filed: |
November 4, 2008 |
PCT NO: |
PCT/EP08/64943 |
371 Date: |
May 21, 2010 |
Current U.S.
Class: |
123/90.15 |
Current CPC
Class: |
F01L 2303/00 20200501;
F01L 2301/00 20200501; F01L 1/3442 20130101 |
Class at
Publication: |
123/90.15 |
International
Class: |
F01L 1/344 20060101
F01L001/344 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 23, 2007 |
DE |
10 2007 056 550.1 |
Claims
1. A modular construction camshaft adjuster for a camshaft drive am
internal combustion engine with a chain or belt wheel, comprising:
at least one radially outwardly oriented wheel rim with a tooth
engagement depth Z; an annular wheel bed around a central circular
opening; and a substantially cylindrical wheel wall with a wall
thickness, which projects substantially in an axial direction from
the annular wheel bed, with the result that the substantially
cylindrical wheel wall and the wheel bed form a cup shape, a
minimum wall thickness of the substantially cylindrical wheel wall
beneath the at least one wheel rim being equal to half the tooth
engagement depth, wherein the cup-shaped chain or belt wheel is
manufactured from a lightweight material and is provided with
radially distributed bores in the annular wheel bed for the purpose
of coaxial mounting on a stator.
2. The camshaft adjuster of claim 1, wherein at least one
substantially radially oriented reinforcing rib extending from the
annular wheel bed to the substantially cylindrical wheel wall is
provided.
3. The camshaft adjuster of claim 1, wherein a reinforcement is
provided at the periphery, extending from the annular wheel bed the
wheel wall.
4. The camshaft adjuster of claim 1, wherein the wheel wall of the
cup-shaped chain or belt wheel projects from an outer edge of a
side of the annular wheel bed which faces away from the camshaft
adjuster.
5. The camshaft adjuster of claim 1, wherein the at least one wheel
rim is arranged in the projecting region of the wheel wall.
6. The camshaft adjuster of claim 2, wherein the reinforcing ribs
are constructed at an angle, in a stepped manner or with rounded
portions.
Description
FIELD OF THE INVENTION
[0001] The invention relates to a modular construction camshaft
adjuster with a chain or belt wheel for the camshaft drive of an
internal combustion engine, having the features of the preamble of
claim 1.
[0002] Camshafts of internal combustion engines are generally
driven by crankshafts via a chain or a toothed belt and are
continuously adjusted within a closed control loop during this
process, with typical adjustment ranges being between 40 and
60.degree. of crank angle. Crank angles to be set are stored in
characteristic maps. Adjustments are made hydraulically, for
example, with the supply coming from the engine oil circuit via an
electrically actuated control valve, and they allow optimized valve
timings using the engine load and speed as parameters. Depending on
the engine concept and the number of adjusters, it is thus possible
to achieve a significant reduction in fuel consumption and exhaust
gas emissions and an increase in power and torque.
[0003] US 2005/0051121 A1 has disclosed a camshaft adjuster with a
chain or belt wheel for a camshaft drive of an internal combustion
engine. The housing of the camshaft adjuster, including a profiled
groove, is composed of aluminum or magnesium. The profiled groove
accommodates the chain or belt wheel, which is manufactured from
steel. The profiled groove complicates the manufacture of the
housing of the camshaft adjuster, and the mounting of the chain or
belt wheel on the housing is an involved process.
[0004] DE 103 03 991 A1 has disclosed a modular construction
camshaft adjuster for the camshaft drive of an internal combustion
engine with a chain or belt wheel, which has a radially outwardly
oriented wheel rim with a tooth engagement depth Z. The chain or
belt wheel is provided with an annular wheel bed around a central
circular opening. A substantially cylindrical wheel wall projects
with a wall thickness X in an axial direction from the annular
wheel bed, with the result that the wheel wall and the wheel bed
together form a cup shape, the wall thickness X of the
substantially cylindrical wheel wall beneath the single wheel rim
being a multiple of the tooth engagement depth Z, giving enough
room for radially distributed bores in the substantially
cylindrical wheel wall to allow coaxial mounting of the chain or
belt wheel on a stator of the camshaft adjuster (see FIG. 2, in the
place cited). The effect of the solid wall thickness X of the
cylindrical wheel wall in DE 103 03 991 A1 is to increase the
weight of the chain or belt wheels and hence to disadvantageously
increase the overall mass of the camshaft adjuster and the chain or
belt wheels.
[0005] Cup-shaped chain or belt wheels of low mass have a
correspondingly limited stability and are deformed when subjected
to high loads by driving chains or belts, something that can
compromise the camshaft drive and thus lead to engine damage.
[0006] It is an object of the invention to provide a modular
construction camshaft adjuster with a chain or belt wheel for the
camshaft drive of an internal combustion engine, having an improved
load capacity combined with a low overall mass.
[0007] The solution is provided by a modular construction camshaft
adjuster with a chain or belt wheel for the camshaft drive of an
internal combustion engine, having the features of claim 1.
Advantageous embodiments are described in the subclaims.
[0008] According to the invention, a modular construction camshaft
adjuster for a camshaft drive of an internal combustion engine has
a chain or belt wheel with an annular wheel bed around a central
circular opening for accommodating a camshaft, on which the chain
or belt wheel is mounted by means of a rotor of the camshaft
adjuster. At least one wheel rim with tooth engagement depths Z is
provided in a radially outward orientation on the chain or belt
wheel. A substantially cylindrical wheel wall with a minimum wall
thickness X projects freely in an axial direction from the annular
wheel bed, at the outer periphery of the latter, and together with
the wheel bed forms a cup shape, the minimum wall thickness X of
the wheel wall projecting from the annular wheel bed, beneath the
at least one wheel rim, being equal to half the tooth engagement
depth Z in order to ensure an adequate load capacity. At least one
wheel rim is arranged in the projecting region of the wheel wall.
According to the invention, the cup-shaped chain or belt wheel is
manufactured from a lightweight material such as aluminum in order
to ensure a low weight. Radially distributed bores in the annular
wheel bed serve to allow coaxial mounting of the chain or belt
wheel on a stator of the camshaft adjuster. This also
advantageously reduces the particularly large distortion of
cup-shaped chain or belt wheels after heat treatment.
[0009] According to an advantageous embodiment of the invention,
the cup-shaped chain or belt wheel is provided with at least one
substantially radially oriented reinforcing rib extending from the
annular wheel bed to the wheel wall to allow weight-optimized
reinforcement at the periphery of the cup-shaped chain or belt
wheel.
[0010] According to a further advantageous embodiment of the
invention, a reinforcement is provided all the way around,
extending from the annular wheel bed to the substantially
frustoconical wheel wall, for the purpose of uniform reinforcement
at the periphery of the cup-shaped chain or belt wheel.
[0011] According to a further advantageous embodiment of the
invention, the wheel wall projects from the outer edge of that side
of the camshaft adjuster which faces away from the camshaft
adjuster.
[0012] According to a further advantageous embodiment of the
invention, the reinforcing ribs are constructed at an angle, in a
stepped manner or with rounded portions to optimize reinforcement
in the given design circumstances and load conditions.
[0013] The invention is explained below with reference to preferred
illustrative embodiments. In the drawing:
[0014] FIG. 1: shows a cup-shaped chain wheel according to the
invention;
[0015] FIG. 2: shows an alternative cup-shaped chain wheel
according to the invention; and
[0016] FIG. 3: shows a further alternative cup-shaped chain wheel
according to the invention.
[0017] FIG. 1: a cup-shaped chain wheel 1 made from a lightweight
material such as aluminum is mounted coaxially on a camshaft
adjuster 2, manufactured in modular form from steel, of an internal
combustion engine (not shown), with bolts 3 distributed uniformly
in the radial direction passing through an annular wheel bed 4 of
the cup-shaped chain wheel 1, a stator 5 and a front cover 6 of the
camshaft adjuster 2. A central circular opening 7 in the annular
wheel bed 4 serves to accommodate a camshaft (not shown), on which
the chain wheel 1 is rotatably mounted by way of the camshaft
adjuster 2. A bearing 8 for the camshaft in a rotor 9 of the
camshaft adjuster 2 has lubricant openings 10.
[0018] A wheel wall 11 of the cup-shaped chain wheel 1, said wheel
wall being substantially cylindrical from the outside, projects
substantially in an axial direction--away from the camshaft
adjuster 2--at the outer periphery of the annular wheel bed 4. Two
wheel rims 12 oriented radially outward, each with tooth engagement
depths Z, are provided in the projecting region of the wheel wall
11, which has a wall thickness X. Respective chains (not shown), by
means of which the camshaft is driven by a crankshaft (not shown),
run over each of the wheel rims 12. The wheel wall 11 of the
cup-shaped chain wheel 1 projects from the periphery of the annular
wheel bed 4 with a minimum wall thickness X which is substantially
constant over its entire axial extent and which is greater than
half the tooth engagement depth Z. The axial extent of the wheel
wall 11 is greater than the width of 2 wheel rims 12.
[0019] FIG. 2: corresponding features are indicated by the
reference signs from FIG. 1. At its free end 13, the wheel wall 11
of the cup-shaped aluminum chain wheel 1 which faces away from the
camshaft adjuster 2 has a minimum wall thickness X which is greater
than the tooth engagement depth Z and which increases in a linear
manner radially inward from the free end 13 as far as the annular
wheel bed 4 to give a substantially frustoconical reinforcement 14
for the wheel bed 4 and the wheel wall 11 all the way around the
periphery thereof, recesses being provided in the reinforcement 14
for the heads of the bolts 3.
[0020] FIG. 3: corresponding features are indicated by the
reference signs from FIGS. 1 and 2. At its free end 13, the
cylindrical wheel wall 11 of the cup-shaped aluminum chain wheel 1
has a minimum wall thickness X which is somewhat greater than the
tooth engagement depth Z. Reinforcing ribs 15, which are
distributed uniformly over the periphery and the wall thickness of
which initially increases in a quasi-linear manner over as much as
approximately 1/3 of the total axial extent of the wheel wall 11 to
about twice the tooth engagement depth Z, extend radially inward
toward the wheel bed 4 from the free end 13 of the cylindrical
wheel wall 11. The wall thickness of the reinforcing ribs 15 then
increases with a radial offset 16 to about three times the tooth
engagement depth Z as far as the annular wheel bed 4. The heads of
the bolts 3 are provided between the ribs 15.
[0021] The cylindrical wheel wall 11 with a minimum wall thickness
X projects freely in an axial direction from the annular wheel bed
4, at the outer periphery of the latter, by an amount which is more
than the width of a wheel rim 12, the width of a wheel rim 12 being
at least 5 mm.
* * * * *