U.S. patent application number 09/731652 was filed with the patent office on 2001-06-14 for chain drive of a v-engine having overhead camshafts.
This patent application is currently assigned to Bayerische Motoren Werke Aktiengesellschaft. Invention is credited to Brandl, Rudolf, Halmanseger, Leonhard.
Application Number | 20010003279 09/731652 |
Document ID | / |
Family ID | 7932151 |
Filed Date | 2001-06-14 |
United States Patent
Application |
20010003279 |
Kind Code |
A1 |
Brandl, Rudolf ; et
al. |
June 14, 2001 |
Chain drive of a V-engine having overhead camshafts
Abstract
A chain drive of a V-engine with overhead camshafts includes
chains which are driven by a crankshaft. In each case the overhead
cam shafts are driven by a separate chain. Tensioner blades
swivellably assigned to a respective slack run of the chains are
acted upon by hydraulic chain tensioners of the same type of
construction. The chain tensioners are arranged in an accessible
manner on the exterior side on the V-engine and interact with
sloped contact ramps on the tensioner blades. The chain tensioners
of the same construction are arranged transversely to one another
on the V-engine and are configured for a reliable venting in each
installed position by including two mutually independently
operating leakage devices.
Inventors: |
Brandl, Rudolf; (Muenchen,
DE) ; Halmanseger, Leonhard; (Kolbermoor,
DE) |
Correspondence
Address: |
Evenson, McKeown, Edwards & Lenahan, P.L.L.C.
Suite 700
1200 G Street, N.W.
Washington
DC
20005
US
|
Assignee: |
Bayerische Motoren Werke
Aktiengesellschaft
|
Family ID: |
7932151 |
Appl. No.: |
09/731652 |
Filed: |
December 8, 2000 |
Current U.S.
Class: |
123/90.31 ;
474/110; 474/111 |
Current CPC
Class: |
F02B 75/22 20130101;
F16H 2007/0859 20130101; F01L 1/02 20130101; F01L 1/022 20130101;
F16H 2007/0872 20130101; F16H 2007/0806 20130101; F16H 2007/0812
20130101 |
Class at
Publication: |
123/90.31 ;
474/110; 474/111 |
International
Class: |
F01L 001/02; F16H
007/08 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 10, 1999 |
DE |
DE 199 59 594.1 |
Claims
What is claimed is:
1. Chain drive of a V-engine having overhead camshafts which are
driven by a crankshaft and each of the camshafts by a separate
chain, in which tensioner blades swivellably assigned to a
respective slackrun of the separate chain are acted upon by
hydraulic chain tensioners, the hydraulic chain tensioners are of
the same construction, wherein the tensioner blades have in free
end areas contact ramps for spherically shaped end sections on
tensioning pistons of the chain tensioners, said contact ramps
being arranged in a sloped manner such that the first chain
tensioner is arranged in an area of an inlet-side longitudinal side
of a first cylinder head, and the second chain tensioner is
arranged in an area of an outlet-side longitudinal side of a second
cylinder head, wherein the chain tensioners are arranged
substantially transverse to one another with the first chain
tensioner vertically aligned to vertically sloped and the second
chain tensioner horizontally aligned to horizontally sloped,
wherein each said chain tensioner is equipped with leakage devices
in both end areas of the tensioning pistons, said leakage devices
being operable for accommodating different venting directions.
2. Chain drive according to claim 1, wherein each said tensioning
piston of the chain tensioners is inserted in a spring-loaded
slidable manner in a hollow screw-in part and bounds a hydraulic
pressure chamber to which a hydraulic medium is fed on a face by a
return valve, a first damping leakage device includes a
substantially radial channel in the screw-in part and an adjoining
circumferential gap between the screw-in part and a
cylinder-head-side screw-in bore as well as an adjoining,
penetrably designed screwed thread-type connection, a second
damping leakage device includes a drainage channel, throttled to an
amount of the leakage, in a piston bottom of the hollow tensioning
piston in the area of the spherically shaped end section, and each
of the damping leakage devices corresponding to the installed
position of the respective chain tensioner being simultaneously
used for system venting.
3. Chain drive according to claim 2, wherein on an interior side of
the hollow tensioning piston, the piston bottom has a conical shape
for joining a supporting disk with a crowned or conical shape,
against which a pressure spring arranged in the tensioning piston
and supported against the screw-in part on the return valve side,
rests on a first side of the supporting disk, and on which a
throttle pin is arranged on a second side of the supporting disk
which throttles the drainage channel in the piston bottom, the
supporting disk having overflow grooves directed to the drainage
channel.
4. Chain tensioner according to claim 2, wherein each of the
screw-in parts of the chain Tensioners is mountable from outside
and comprises a screw head with a sealing ring, whereby a
circumferential groove is used for an inflow of hydraulic medium
from the respective cylinder head to the hydraulic pressure
chamber, said hydraulic pressure chamber being valve controlled,
and said circumferential groove being connected with overflow
channels and sealed off from the circumferential gap of the first
damping leakage device by an O-ring.
5. A hydraulic chain tensioner for a chain drive of an engine
acting upon a tensioner blade swivellably assigned to a slackrun of
a chain, wherein the tensioner blade has in a free end area a
contact ramp for a spherically shaped end section on a tensioning
piston of the chain tensioner, said chain tensioner being equipped
with leakage devices in both ends of the tensioning piston for
venting when positioned in respective different angular orientation
positions in use on an engine.
6. Hydraulic chain tensioner according to claim 5, wherein said
tensioning piston of the chain tensioner is inserted in a
spring-loaded slidable manner in a hollow screw-in part and bounds
a hydraulic pressure chamber to which a hydraulic medium is fed on
a face by a return valve, wherein said tension piston includes a
first damping leakage device including a substantially radial
channel in the screw-in part and an adjoining circumferential gap
between the screw-in part and a cylinder-head-side screw-in bore as
well as an adjoining, penetrably designed screwed thread-type
connection. wherein said tensioning piston includes a second
damping leakage device including a drainage channel, throttled to
an amount of leakage, in a piston bottom of the hollow tensioning
piston in an area of the spherically shaped end section, and
wherein each of the damping leakage devices, corresponding to the
installed position of the chain tensioner, being simultaneously
used for system venting.
7. Method of making a chain drive of an engine having overhead
camshafts, which are driven by a crankshaft and each of the cam
shafts by a separate chain, comprising the acts of; providing
tensioner blades swivellably assigned to a respective slackrun of
each of the separate chains, providing hydraulic chain tensioners,
each of which are of the same construction, for acting upon the
tensioner blades, arranging a first of the chain tensioners in an
area of an inlet-side longitudinal side of a first cylinder head,
and arranging a second of the chain tensioners in an area of an
outlet-side longitudinal side of a second cylinder head, wherein
the tensioner blades have in free end areas contact ramps of
spherically shaped end sections on tensioning pistons of the chain
tensioners, said contact ramps being arranged in a sloped manner,
and wherein the chain tensioners are substantially transverse to
one another with the first chain tensioner vertically aligned to
vertically sloped and the second chain tensioner horizontal aligned
to horizontal sloped, and each said chain tensioner is equipped
with leakage devices, used for venting in different directions, in
both end areas of the tensioning piston.
Description
BACKGROUND AND SUMMARY OF THE INVENTION
[0001] This application claims the priority of German Patent
Document 199 59 594.1, filed Dec. 10, 1999, the disclosure of which
is expressly incorporated by reference herein.
[0002] This invention relates to a chain drive of a V-engine having
overhead camshafts which are driven by a crankshaft, in each case,
by a separate chain, in which case tensioner blades swivellably
assigned to a respective slack run of the chains are acted upon by
hydraulic chain tensioners of the same type of construction.
[0003] A chain drive of this type for a V-engine is known, for
example, from German Patent Document DE 39 21 275 A1. The tensioner
blades acting upon the respective slack run of the respective chain
are in each case acted upon by chain tensioners which are arranged
between the slack run and the tension run of the respective chain
on the respective face of a pertaining face of a pertaining
cylinder bank and of the pertaining cylinder head. These chain
tensioners, which, because of their arrangement, have the same
construction, are therefore not easily accessible if required.
[0004] It is an object of the invention to provide, for a chain
drive of the above-mentioned type having chain tensioners
accessible from the outside, an arrangement therefor as well as a
further development for chain tensioners of the same construction
on V-engines.
[0005] This object is achieved by the tensioner blades having in
their free end areas contact ramps for spherically designed end
sections on tensioning pistons of the chain tensioners of the same
construction, which contact ramps are arranged in a sloped manner
such that the first chain tensioner is arranged in the area of an
inlet-side longitudinal side of a first cylinder head and the
second chain tensioner is arranged in the area of an outlet-side
longitudinal side of a second cylinder head, wherein the chain
tensioners which are arranged with respect to one another
essentially in a transverse direction with a vertically aligned to
vertically sloped first chain tensioner and a horizontally aligned
to horizontally sloped second chain tensioner in each case are
equipped with leakage devices used for different venting
directions, in both end areas of each tensioning piston.
[0006] By the design according to the invention of the tensioner
blades with contact ramps arranged in a sloped manner and known per
se from German Patent Document DE 42 06 071 C2, for spherically
designed end sections of the tensioning pistons, the chain
tensioners can be arranged in an advantageous manner to be
accessible from the outside or mountable relative to the housing of
the respective V-engine. According to an advantageous feature of
preferred embodiments of the invention, the chain tensioners are
arranged with respect to one another in a transverse direction and
each of the chain tensioners of the same construction has two
mutually independently operating leakage devices, for the
advantageous venting of the chain tensioners in the respective
installed position.
[0007] Advantageous features of preferred embodiments of the
invention are described in the claims.
[0008] The invention will be described by an embodiment illustrated
in the drawing.
[0009] Other objects, advantages and novel features of the present
invention will become apparent from the following detailed
description of the invention when considered in conjunction with
the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a part sectional schematic view of chain drives
for overhead camshafts of a V-engine illustrated in a front view
with chain tensioner assemblies and preferred embodiments
constructed according to the present invention with chain
tensioner;
[0011] FIG. 2 is an enlarged longitudinal sectional view of a chain
tensioner assembly constructed according to preferred embodiments
of the invention.
DETAILED DESCRIPTION OF THE DRAWINGS
[0012] In the case of a chain drive 1, as shown in FIG. 1, of a
V-engine 2 with overhead camshafts 3, 4, these camshafts are driven
by a crankshaft 5 in each case by a separate chain 6, 7, in which
case tensioner blades 8 swivellably assigned to a respective slack
run 6', 7' of the chains 6, 7 are acted upon by hydraulic chain
tensioners 9, 9' of the same type of construction.
[0013] According to the invention, the tensioner blades 8 have in
their free end areas 8' contact ramps 10 for spherically designed
end sections 11 on tensioning pistons 12 of the chain tensioners 9,
9'. The contact ramps 10 are arranged in a sloped manner and such
that the first chain tensioner 9 is arranged in the area of an
inlet-side longitudinal side 14' of a first cylinder head 14 of the
V-engine 2, and the second chain tensioner 9' is arranged in the
area of an outlet-side longitudinal side 15 of a second cylinder
head 16 of the V-engine 2. Further, for the ideal venting of the
hydraulic system of the chain tensioners 9, 9', it is provided
according to the invention that the chain tensioners 9, 9' are
arranged with respect to one another essentially in a transverse
direction. A vertically sloped first chain tensioner 9 and a
horizontally sloped second chain tensioner 9' are equipped with
leakage devices 17, 18 used for different venting directions,
disposed in both end areas of each tensioning piston 12.
[0014] As also indicated in detail in FIG. 2, each tensioning
piston 12 of the chain tensioners 9, 9' is inserted in a
spring-loaded slidable manner in a hollow screw-in part 19 and
bounds a hydraulic pressure chamber 20 to which a hydraulic medium
is fed on the face by way of a return valve 21. For a first damping
leakage 17 used for venting in the case of the vertically aligned
first chain tensioner 9, an essentially radial channel 22 in the
screw-in part 19 and an adjoining circumferential gap 23 between
the screw-in part 19 and a cylinder-head-side screw-in bore 24 as
well as an adjoining, penetrably designed screwed thread-type
connection 25 are provided. For a better penetrability of the
screwed thread-type connection 25, the latter can be constructed
with a narrow groove 26.
[0015] For a second damping leakage 18 used for the venting in the
case of the chain tensioner 9' extending horizontally, a drainage
channel 28, which is throttled to the amount of the leakage, is
provided in a piston bottom 27 of the hollow tensioning piston 12
which carries the spherically designed end section 11.
[0016] In addition, at a normal chain tension, both damping
leakages 17 and 18 of each chain tensioner 9, 9' can cause a
parallel damping, as known, for example, per se from German Patent
Document DE 40 35 823 C1.
[0017] Furthermore, it is illustrated particularly in FIG. 2 that,
on the interior side of the hollow tensioning piston 12, the piston
bottom 27 has a conical design for the joining of a supporting disk
29 constructed in a crowned or conical shape, against which a
pressure spring 30 arranged in the tensioning piston 12 and
supported against the screw-in part 19 on the return valve side
rests on the one side and on which a throttle pin 31 is arranged on
the other side which throttles the drainage channel 28 in the
piston bottom 27, the supporting disk 29 having overflow grooves 32
directed to the drainage channel 28.
[0018] Finally, each screw-in part 19 of the chain tensioners 9,
9', which can be mounted from the outside, comprises a screw head
33 with a sealing ring 34 which, on one side, seals off a
circumferential groove 36 which is used for the inflow of hydraulic
medium from the respective cylinder head 14, 16 to the
valve-controlled pressure chamber 20, which is connected with
overflow channels 35 and is sealed off with respect to the
circumferential gap 23 of the first damping leakage 17 by of an
O-ring 37.
[0019] The foregoing disclosure has been set forth merely to
illustrate the invention and is not intended to be limiting. Since
modifications of the disclosed embodiments incorporating the spirit
and substance of the invention may occur to persons skilled in the
art, the invention should be construed to include everything within
the scope of the appended claims and equivalents thereof.
* * * * *