U.S. patent application number 14/494452 was filed with the patent office on 2015-03-26 for cam phaser with eccentric lantern gear component.
The applicant listed for this patent is iwis motorsysteme GmbH & Co. KG. Invention is credited to Michael FRANK, Christoph LUNK, Reinhard MULLER, Alexander SALZSEILER.
Application Number | 20150083061 14/494452 |
Document ID | / |
Family ID | 52689831 |
Filed Date | 2015-03-26 |
United States Patent
Application |
20150083061 |
Kind Code |
A1 |
MULLER; Reinhard ; et
al. |
March 26, 2015 |
CAM PHASER WITH ECCENTRIC LANTERN GEAR COMPONENT
Abstract
A cam phaser transmission device is adjustable in rotation angle
with a drive gear and output gear arranged coaxial to a rotation
axis of the transmission device, having a revolving transmitter
element and actuating device. The transmitter element is arranged
eccentric relative to the rotation axis and formed as a lantern
element. The lantern element comprises a transmitter disk disposed
eccentric to the rotation axis and comprising pins protruding
concentrically to the transmitter disk relative to the face side of
the disk. The lantern element in sections engages with the drive
gear and output gear and is by an eccentric portion of the
actuating device movable eccentrically to the rotation axis to move
the drive gear and output gear relative to each other. In an
inverted embodiment, the drive gear and the output gear are formed
as lantern elements each engaging with a lantern toothing on the
transmitter disk.
Inventors: |
MULLER; Reinhard;
(Landsberg, DE) ; FRANK; Michael; (Otterfing,
DE) ; SALZSEILER; Alexander; (Munchen, DE) ;
LUNK; Christoph; (Munchen, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
iwis motorsysteme GmbH & Co. KG |
Munchen |
|
DE |
|
|
Family ID: |
52689831 |
Appl. No.: |
14/494452 |
Filed: |
September 23, 2014 |
Current U.S.
Class: |
123/90.15 |
Current CPC
Class: |
F01L 1/352 20130101;
F01L 2820/01 20130101; F01L 2250/02 20130101 |
Class at
Publication: |
123/90.15 |
International
Class: |
F01L 1/344 20060101
F01L001/344; F01L 1/047 20060101 F01L001/047 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 24, 2013 |
DE |
1020130158443. |
Claims
1. A cam phaser for an internal combustion engine with a
transmission device adjustable in the angle of rotation with a
drive gear and an output gear, where said drive gear and said
output gear are arranged coaxial relative to an axis of rotation of
said transmission device, and with a transmitter element revolving
eccentrically relative to said axis of rotation and an actuating
device, where said actuating device comprises an eccentric portion
acting upon said transmitter element, wherein said transmitter
element is formed as a lantern element, where said lantern element
comprises a transmitter disk being disposed eccentric relative to
said axis of rotation with a plurality of pins protruding
concentrically to said transmitter disk relative to a first face
side of said transmitter disk, where said lantern element in
sections engages with said drive gear and in sections with said
output gear, and where said lantern element is by said eccentric
portion movable eccentrically about said axis of rotation in order
to move said drive gear and said output gear relative to each
other, and wherein said actuating device comprises a power take-off
shaft on which said eccentric portion is arranged and which is
coupled to an actuating drive, where said drive gear is via a
timing assembly coupled in a fixed angle of rotation to the
crankshaft and said output gear to a camshaft.
2. The cam phaser according to claim 1, wherein said transmitter
disk also on a second face side comprises a plurality of pins
protruding concentrically to said transmitter disk relative to said
second face side.
3. The cam phaser according to claim 2, wherein said pins
protruding concentrically relative to said first face side and said
pins protruding concentrically relative to said second face side
are arranged on different radii of said transmitter disk.
4. The cam phaser according to claim 2, wherein the number of said
pins protruding concentrically relative to said first face side
differs from the number of said pins protruding concentrically
relative to said second face side.
5. The cam phaser according to claim 1, wherein said drive gear and
said output gear each comprise a lantern gear which are in sections
engaged with said lantern element.
6. The cam phaser according to claim 5, wherein said drive gear and
said output gear comprise externally-toothed lantern gears.
7. The cam phaser according to claim 5, wherein said drive gear and
said output gear are formed as hollow gears engaging with an
internal toothing with said lantern element.
8. The cam phaser according to claim 1, wherein said transmission
device is configured as a two-stage gear, said two-stage gear
comprises a first and a second lantern element disposed eccentric
relative to said axis of rotation and a transition element which in
sections engages with said first lantern element and in sections
with said second lantern element, where said drive gear in sections
engages with said first lantern element and said output gear in
sections engages with said second lantern element.
9. The cam phaser according to claim 1, wherein said actuating
drive is an electric motor.
10. The cam phaser according to claim 1, wherein a bearing seat, on
which said eccentrically revolving transmitter disk is mounted, is
provided on said eccentric portion.
11. The cam phaser for an internal combustion engine with a
transmission device adjustable in the angle of rotation with a
drive gear and an output gear, where said drive gear and said
output gear are arranged coaxial relative to an axis of rotation of
said transmission device, and with a transmitter element revolving
eccentrically relative to said axis of rotation and an actuating
device, where said actuating device comprises an eccentric portion
acting upon said transmitter element, wherein said drive gear and
said output gear are formed as lantern elements comprising a
plurality of pins disposed concentric relative to said axis of
rotation, and that said transmitter element is formed as a lantern
gear, where said lantern gear comprises a transmitter disk being
disposed eccentric relative to said axis of rotation and having a
first and a second lantern toothing which are arranged concentric
relative to said transmitter disk, where said lantern elements of
said drive gear and said output gear each in sections engage with
said first and said second lantern toothing of said transmitter
disk, and where said transmitter disk is by said the eccentric
portion movable eccentrically about said axis of rotation in order
move said drive gear and said output gear relative to each other;
and wherein said actuating device comprises a power take-off shaft
on which said eccentric portion is arranged and which is coupled to
an actuating drive, where said drive gear is via a timing assembly
coupled in a fixed angle of rotation to said crankshaft and said
output gear to a camshaft.
12. The cam phaser according to claim 11, wherein said actuating
drive is an electric motor.
13. The cam phaser according to claim 11, wherein a bearing seat,
on which said eccentrically revolving transmitter disk is mounted,
is provided on said eccentric portion.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to foreign German patent
application No. DE 102013015844.3, filed on Sep. 24, 2013, the
disclosure of which is incorporated by reference in its
entirety.
FIELD OF THE INVENTION
[0002] The present invention relates to a cam phaser transmission
device adjustable in the angle of rotation with a drive gear and an
output gear, where the drive gear and the output gear are arranged
coaxial relative to the axis of rotation of the transmission
device, and with a transmitter element revolving eccentrically
about the axis of rotation and an actuating device, where the
actuating device comprises an eccentric portion acting upon the
transmitter element.
BACKGROUND
[0003] Conventional planetary gear mechanisms are used in the art
as single or multi-stage gears for very different applications. In
this, the planetary gear mechanisms can be designed as a toothed
gear mechanism or a friction gear mechanism and can, in addition to
axes fixed to the frame not changing their position in the gear
housing, also comprise revolving axes revolving in circular orbits
in the gear mechanism. In addition to the transmission of a
rotational motion, addition and distribution gears are with a
planetary gear mechanism easily realized. Since planetary gear
mechanisms always have at least two shafts fixed to the frame and
one revolving shaft, at least one two-stage gear transmission is
always given with an overall relatively high transmission ratio in
contrast to simple single-stage stationary gear mechanisms. With
arranging an outer ring gear and an inner sun gear in one plane, a
particularly short planetary gear mechanism can be realized.
[0004] The possibility of a planetary gear mechanism in a
three-shaft operation using two shafts for driving the gear
mechanism and always using one shaft for the output enables a large
range of different applications, for example, for driving hybrid
vehicles. Transmission devices adjustable in the angle of rotation
that are used as cam phasers for increasing performance and fuel
economy in modern internal combustion engines are usually designed
as single-stage or multi-stage planetary gear mechanisms. In this,
a second drive shaft controls adjustment of the angle of rotation
between the first drive shaft and the output shaft.
[0005] Cam phasers provide adjustment of valve opening times to the
load behavior of the engine during operation of internal combustion
engines. The adjustment of overlap times of the exhaust valves and
intake valves allows not only for fuel savings as well as power and
torque gains but also for reduction in emissions, which is
important in view of the ever-increasing requirement to comply with
emission standards.
[0006] In addition to planetary gear mechanisms, a whole number of
different designs and concepts for transmission devices that are
adjustable in the angle of rotation are used as cam phasers. Most
widely spread are nowadays hydraulic cam phasers that are based on
a swing motor known from hydraulic technology and equipped with
several vanes to increase the transmittable torque. Hydraulic cam
phasers are in the internal combustion engine driven via the engine
oil circuit, which is why operation of the cam phaser depends on
the pressure and the temperature of the engine oil, and therefore
on the operating temperature and the rotational speed of the
internal combustion engine.
[0007] In addition, electric cam phasers are known that operate
independently of oil pressure. Due to the electric actuation of the
cam phaser, they can also be adjusted in an internal combustion
engine that is not operational and additional hydraulic pumps can
be avoided in the engine oil circuit. DE 41 10 195 A1 describes an
electric cam phaser in which an electric motor effects relative
adjustment of the angle of rotation of the camshaft relative to the
camshaft gear. Either a threaded portion with a spline or a
planetary gear with a self-locking transmission ratio is used as an
actuating mechanism. EP 573 019 B1 further describes a parallel
planetary gear mechanism with internally toothed gear wheels in
which several eccentric elements driven by a shaft eccentrically
rotate a plurality of gear wheels with external toothing and in
sections make them engage with the internal toothing of the ring
gears.
[0008] The cam phaser or transmission devices adjustable in the
angle of rotation known in prior art entail various problems
depending on the design and embodiment. Whereas hydraulic swing
motors are in a negative manner dependent upon the pressure and
temperature of the engine oil, the respective cam phasers with
electric actuation have drawbacks in terms of actuating speed, the
required actuating energy, self-locking or of running smoothly, in
particular, when being embodied as eccentric gear mechanisms.
[0009] Although the designs and concepts for cam phasing known in
the art have overall proven themselves for the use in modern
internal combustion engines, there are continuous efforts to
realize optimized designs, especially with regard to the large
quantities common in the automotive industry, and to eliminate or
minimize existing problems. In view of the ongoing innovative
activity to increase efficiency of internal combustion engines,
there is furthermore generally the necessity to describe new
solutions to replace employed designs with optimized or inexpensive
concepts.
SUMMARY OF THE INVENTION
[0010] The present invention is therefore based on the object to
provide a cam phaser transmission device adjustable in the angle of
rotation to improve problems of transmission devices known in prior
art with relative adjustment of two drive components and to enable
high positioning accuracy and operational reliability at the lowest
possible production effort.
[0011] This object is solved in that the transmitter element is
formed as a lantern element, where the lantern element comprises a
transmitter disk being disposed eccentric to the axis of rotation
and having a plurality of pins that protrude concentric to the
transmitter disk on a first face side of the transmitter disk,
where the lantern element partly engages with the drive gear and
partly engages with the output gear, and where the lantern element
is by the eccentric portion movable via the transmitter disk
eccentrically about the axis of rotation in order to move the drive
gear and the output gear relative to each other. With the use of
lantern elements that on the side of the drive and output gears
engage with suitable positive-fit elements, for example, lantern
gears, gear wheels or corrugated bands, the use of precision-ground
or braced gears can in transmission devices or gear mechanisms
adjustable in the angle of rotation be dispensed with, whereby a
major cost factor in the manufacture of power-split gear mechanisms
can be saved. In this, suitable lantern elements are generally
composed of at least one disk on which a plurality of pins are
provided with regular spacing concentric to the center of the disk
and are welded or riveted into associated bores on the disk or
otherwise attached and protrude perpendicular relative to the
respective face side, i.e. in an axially parallel manner to the
disk axis. In the redirection of forces of the lantern element onto
the drive gear and the output gear, the pins are essentially
subjected to shear stress, so that the wear of the toothing of gear
components otherwise occurring can be reduced.
[0012] In conventional use, lantern elements are used for slow
drive elements in high-contamination environments, such as in
mining, where high contamination must not lead to malfunction of a
drive. In addition to the limitation to relatively only low drive
speeds, lantern elements can there also transmit only relatively
small forces, as the associated lantern gears are in conventional
applications strongly rounded at the base circle and the base of
the tooth is thereby weakened. In contrast to the conventional
application of lantern elements, the transmission device according
to the invention uses lantern elements for both high speeds as well
as for relatively high forces.
[0013] While transmission devices adjustable in the angle of
rotation common today are in the range of high transmission ratios,
in particular as cam phasers in internal combustion engines,
primarily implemented by using multi-stage planetary gears of which
the power take-off is provided with a corresponding high-revving
motor, the solution according to the invention enables a single or
multiple stage transmission device which due to the integrative
co-action of three rotating components and an actuating device
enables a direct very high reduction ratio despite requiring a
small installation space. This design according to the invention is
not a mere compilation of partially optimized components, but
rather an integral, customized, complex design of an intelligent
system for power transmission.
[0014] The key element of this transmission device adjustable in
the angle of rotation according to the invention is there the
transmitter element formed as a lantern element which in sections
engages with the drive gear and in sections with the output gear
and is positioned eccentric relative to the axis of rotation. The
lantern element, due to its special design as an embedded rigid
non-elastic wobble body, there enables a power increase when
engaged with the drive gear and the output gear in a kind of wedge
effect. Due to the eccentric arrangement of the circular
transmitter disk, a flat cylindrical disk with a concentric recess,
the radius of which is by a multiple larger than its thickness and
the main axis of which is offset in an axially parallel manner
relative to the axis of rotation of the transmission device, a
wobbling motion of the transmitter disk occurs during actuation of
the transmitter element by the eccentric portion of the actuating
device together with a change in the axis position of the disk
which rotates with the eccentricity c about the axis of
rotation.
[0015] While the wobbling transmitter disk and the pins protruding
relative to a first face side perform a radial motion relative to
the axis of rotation, a tangentially acting force results at the
drive gear and the output gear leading to a relative motion. The
design of the drive gear, the output gear and the transmitter
element is there coordinated such that the circular transmitter
disk performs an off-center wobbling circular motion with the
eccentricity .epsilon. relative to the axis of rotation. With the
design according to the invention on the basis of an eccentrically
rotating, wobbling lantern element, large reduction ratios can be
achieved depending on the design and arrangement of the elements.
In the main use case of application of transmission devices
adjustable in the angle of rotation, the use as a cam phaser, a
respective high reduction enables the use of small-sized actuators
and low backlash to the actuator by the self-locking of the high
transmission ratio.
[0016] A preferred embodiment provides that the transmitter disk
also comprises a plurality of pins on the second face side which
are arranged concentric and protrude relative to the second face
side. In contrast to a one-sided engagement of the drive or output
gear on the inner and outer side of the ring of pins, the
ring-shaped arrangement of pins on both face sides of the
transmitter disk enables independent engagement of the drive and
the output gear with freely selectable transmission ratios. It is
there advantageous if the pins protruding concentrically relative
to the first face side and the pins protruding concentrically
relative to the second face side of the transmitter disk are
arranged on different radii of the transmitter disk. The different
radii of the concentrically disposed rings of pins, i.e. the
different distance between the center of the transmitter disk and
the circular line of the pins disposed in a ring-shaped manner
increases the freedom of design for drive and output gears being in
engagement with this lantern element. For different transmission
ratios, the number of pins protruding concentrically relative to
the first face side and the number of pins protruding
concentrically relative to the second face side can there differ.
The different number of pins equally spaced at the circumference on
a circular line enables different transmission ratios irrespective
of the design of the drive gear and the output gear. The pins
protruding concentrically relative to the first and respectively
second face side of the transmitter disk wobble together with the
transmitter disk relative to the axis of rotation of the
transmission device, so that they engage only in sections with the
drive gear and the output gear.
[0017] An advantageous embodiment provides that the number of pins
protruding concentrically relative to the first face side and/or
the number of pins protruding concentrically relative to the second
face side is as large as possible, for example, is greater than 50.
With a large number of pins protruding relative to a planar side,
high transmission ratios can be achieved already with a
single-stage transmission device, i.e. a high reduction of the
power take-off via the actuating device. The number of positive-fit
elements on the drive gear and on the output gear preferably
differs by 2, in particular by 1, from the number of protruding
pins, i.e. is only slightly greater than or less than the number of
pins.
[0018] The drive gear and the output gear can advantageously
comprise lantern gears that engage in sections with the lantern
element. Unlike milled or ground gears that require high-precision
manufacturing in particular for planetary gear mechanisms, lantern
gears can be produced by simple punching. To realize the thinnest
possible transmission device, the drive gear and the output gear
can there externally toothed lantern gears that use the inner ring
space of the one ring of pins protruding from at least one face
side of the transmitter disk, where the drive gear and the output
gear each engage in sections on one face side with the protruding
pins. Alternatively, the drive gear and the output gear can be
configured as ring gears and with an internal toothing engaging
from the outside with the lantern element. The teeth of the lantern
gear can in an advantageous modification be designed as being flat
in order to avoid weakening the base of the tooth. Such flat teeth,
receiving only about half or slightly more than half of the pins,
allow high speeds during engagement of the lantern elements with
the lantern gears.
[0019] A special design of the transmission device adjustable in
the angle of rotation provides that the transmission device is
designed as a two-stage gear, the two-stage gear comprises a first
and a second lantern element disposed eccentric relative to the
axis of rotation and a transition element which in sections engages
with the first lantern element and in sections with the second
lantern element, where the drive gear in sections engages with the
first lantern element and the output gear in sections engages with
the second lantern element. The configuration of the transmission
device as a two-stage gear allows a very high reduction ratio and
very good self-locking. Depending on the manner in which the drive
gear and the output gear engage with the first and the second
lantern element, the configuration as a two-stage gear allows for a
change of the sign of the transmission, so that there can be a
subtraction of transmission rations slightly differing from each
other, whereby extremely large transmission rations can be
realized.
[0020] In an inverted configuration of the invention, the drive
gear and the output gear are formed as lantern elements having a
plurality of pins arranged concentric relative to the axis of
rotation, and the transmitter element is formed as a lantern gear,
where the lantern gear comprises a transmitter disk disposed
eccentric relative to the axis of rotation with a first and a
second lantern toothing which are arranged concentric to the
transmitter disk, where the lantern elements of the drive gear and
the output gear each in sections engage with the first and the
second lantern toothing of the transmitter disk and where the
transmitter disk is eccentrically movable about the axis of
rotation by the eccentric portion in order to move the drive gear
and the output gear relative to each other The transmitter element
can there comprises two lantern gears of different circumference
connected to each other in a rotationally-fixed manner eccentric to
the axis of rotation which by the eccentric portion of the
actuating device engage with the pins, being arranged concentric
relative to the axis of rotation, of the lantern elements of the
drive gear and the output gear. The basic mode of operation of this
inverted configuration of a transmission device adjustable in the
angle of rotation does not differ from the embodiment described
above having an eccentrically revolving lantern element, for which
reason reference is respectively presently made to the advantages
of the invention already described above.
[0021] A main embodiment provides that the actuating device
comprises a power take-off shaft on which auxiliary shaft the
eccentric portion is arranged and which is coupled to an actuating
drive, preferably to an electric motor. Such a power take-off shaft
not only enables simple coupling of an actuator and thereby a
simple drive but also simple formation of the circular eccentric
portion. For an advantageous configuration, bearing seats can be
provided on the power take-off shaft on which the drive gear and
the output gear are mounted. This eliminates the need for any
further mounting of the transmission device and a counter bearing
by the output shaft associated with the output gear, for the cam
phaser, the associated camshaft.
[0022] For operating the adjustment of the angle of rotation as
smooth as possible via the actuating device, a bearing seat can be
provided on the eccentric portion on which the eccentrically
revolving transmitter disk is mounted. In addition to simple ball
bearings, roller bearings or sliding bearings can also be provided
between the transmitter disk wobbling about the axis of rotation
and the circular eccentric portion disposed eccentric relative to
the axis of rotation.
[0023] The present invention also relates to a cam phaser for an
internal combustion engine with a transmission device adjustable in
the angle of rotation, where the drive gear is by a timing assembly
(timing chain) coupled at a fixed angle of rotation to the
crankshaft and the output gear to a camshaft. Such a cam phaser,
despite the use of simple components, enables reliable adjustment
of the angle of rotation of the camshaft relative to the camshaft
gear of an internal combustion engine with a large reduction ratio
and good self-locking.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] An embodiment of the transmission device adjustable in the
angle of rotation shall below be explained with reference to
drawings. In the drawings:
[0025] FIG. 1 shows a cross-sectional view of a transmission device
adjustable in the angle of rotation according to the invention, in
particular for a cam phaser of an internal combustion engine;
[0026] FIG. 2 shows a side view of the transmission device of FIG.
1 from the direction of the power take-off shaft;
[0027] FIG. 3 shows perspective side view of the transmission
device of FIG. 1;
[0028] FIG. 4 shows a partially cut-away perspective side view of
the transmission device of FIG. 3; and
[0029] FIG. 5 shows a schematic view of a cam phaser according to
the invention with the transmission device of FIG. 1.
DETAILED DESCRIPTION
[0030] The sectional view in FIG. 1 shows an embodiment of a
transmission device 1 adjustable in the angle of rotation according
to the invention with an axis of rotation D that can be used as a
cam phaser 24 in an internal combustion engine. The transmission
device 1 shown in this sectional view comprises a power take-off
shaft 2 of a actuating device 6 positioned along the axis of
rotation D, and a drive gear 3 and a output gear 4 which are
rotatably mounted on the power take-off shaft 2, as well as a
transmitter element 5 enabling engagement in sections with the
drive gear 3 and the output gear 4. The power take-off shaft 2
comprises a drive bearing seat 7 and an output bearing seat 8 which
are each provided with a double ball bearing 9 on which in turn the
drive gear 3 and the output gear 4 are positioned coaxial to the
axis of rotation D and mounted rotatably relative to the power
take-off shaft 2. An eccentric portion 10 is provided on the power
take-off shaft 2 between the drive bearing seat 7 and the output
bearing seat 8. The eccentric portion 10 having a circular
configuration comprises an eccentric axis E which is concentric
relative to the eccentric portion 10, but at the same time is
arranged offset from the axis of rotation D of the power take-off
shaft 2 by the eccentricity e. With each rotational motion of the
power take-off shaft 2, the position of the axis E relative to the
axis of rotation D therefore changes, so that the eccentric axis E
of the circular eccentric portion 10 wobbles with every rotational
motion of the power take-off shaft 2 with the eccentricity .English
Pound. about the axis of rotation D. Provided on the circumference
of the circular eccentric portion 10 is an eccentric bearing seat
11 on which a ball bearing 12 is arranged, on which the transmitter
disk 13 of the transmitter element 5 is rotatably supported
relative to the eccentric portion 10. Also the circular
bending-resistant transmitter disk 13 therefore wobbles together
with the eccentric portion 10 with the eccentricity .English Pound.
about the axis of rotation D.
[0031] A plurality of pins is provided respectively on the first
face side 14 and the second face side 15 of the transmitter disk 13
and arranged concentric to the eccentric axis E with equal spacing
on a circular path. The pins 16 extend through respective bores 17
on the transmitter disk 13 in which the pins are fixedly anchored
using known joining methods of chain technology, for example
rivets. The fixed joining of the pins 16 in the bores 17 of the
transmitter disk 13 enables the production of a stable and highly
accurate lantern element 20, i.e. the revolving transmitter element
can in the transmission device 1 according to the invention
adjustable in the angle of rotation also be used during higher
speeds and higher transmission of forces. Alternatively, the pins
16 can also be disposed in the circumferential surface of the
transmitter disk 13 and protrude relative to a face side 14,
15.
[0032] The drive gear 3 is on the side facing the transmitter disk
13 provided with a lantern gear 18 which is arranged in the inner
space formed by the pins 16 protruding form the first face side 14
of the transmitter disk 13 and in sections engages with the pins 16
protruding at the first face side 14. Also on the side of the
output gear 4 facing the transmitter disk 13, a lantern gear 19 is
provided which is arranged in the inner space formed by the pins 16
protruding on the second face side 15 of the transmitter disk 13
and in sections engages with the pins 16 protruding on the second
face side 15.
[0033] Due to the eccentricity e of the transmitter disk 13
relative to the axis of rotation D, the pins 16 protruding on the
first face side 14 and the second face side 15 each only in
sections completely engage with the lantern gears 18 and 19,
respectively, of the drive gear 3 and the output gear 4, which can
be seen in FIG. 1 in the lower part of the image. On the opposite
side on which the eccentric axis E is offset by the eccentricity e
relative to the axis of rotation D, a gap S exists between the pins
16 of the lantern element 20 and the lantern gears 18, 19 of the
drive gear 3 and the output gear 4. The spacing there between the
pins 16 and the lantern gears 18, 19 is in the gap S approximately
twice as large as the eccentricity e.
[0034] The double ball bearing 9 positioned on the drive bearing
seat 7 is in the side view of the transmission device 1 in FIG. 2
visible in addition to the power take-off shaft 2 protruding
relative to the drive 3 as well as the shaft stub 21 of the power
take-off shaft 2 for attaching an actuator, e.g. an electric motor
28, for driving the actuating device 6. The drive gear 3 on the
outer side facing away from the lantern gear 18 further comprises a
circumferential annular groove 22, 26 which enables secure
attachment of a camshaft gear wheel 26 on the drive gear 3. A
circumferential annular groove 23 is similarly provided on the
outer side of the output gear 4 facilitating the attachment on a
camshaft 25.
[0035] FIGS. 3 shows a perspective side view of the transmission
device 1 according to the invention from the side of the output
gear 4 in which the circumferential groove 23 for connecting the
camshaft 25 is easily recognizable. The power take-off shaft 2
mounted in the output gear 4 by the double ball bearing 8 is
further visible in the center of the output gear 4. The transmitter
disk 13 revolving in a wobbling manner relative to the axis of
rotation D is arranged between the output gear 4 and the drive gear
3 arranged on the side facing away. On the side of the transmitter
disk 13 facing the drive gear 3, a plurality of equidistant bores
17 arranged concentric relative to the eccentric axis E are visible
in which the pins 16 protruding on the first face side 14 are
attached. The pins protruding on the second face side 15 of the
transmitter disk 13 are in the perspective view of FIG. 3 hidden
behind the output gear 4. The pins 16 protruding on the first face
side of the transmitter disk 13 in sections engage with the lantern
gear 18 of the output gear 3 which is disposed within the circle of
pins on the first face side 14.
[0036] The perspective side view in FIG. 4, like FIG. 3, shows the
transmission device 1 according to the invention from the side of
the output gear 4, the drive gear 3 and output gear 4, however, are
omitted in this view so that essentially only the transmitter
element 5 with the actuating device 6 is shown. This representation
very nicely shows the arrangement of the pins 16 on the second face
side 15 of the transmitter disk 13 which protrude the same distance
on a concentric circle relative to the axis E of the second face
side 15. The pins 16 also on the first face side 14 of the
transmitter disk 13 protrude perpendicular to the transmitter disk
13 and axially parallel to the axis of rotation D on the first face
side 14. Accordingly, this lantern element 20 of a transmission
device 1 according to the invention on the first and the second
face sides 14, 15 comprises the pins 16 for engagement with the
associated lantern gears 18, 19.
[0037] FIG. 5 shows a partially cut-away schematic side view of a
cam phaser 24 according to the invention for an internal combustion
engine based on a transmission device 1 adjustable in the angle of
rotation. The transmission device 1 is with the ring flange formed
by the double ball bearing 9 seated in a hollow cylindrical end of
a camshaft 25 of the internal combustion engine, where the hollow
cylindrical seat of the camshaft 25 protrudes up into the groove 23
of the output gear 4. The camshaft 25 therefore revolves together
with the output gear 4 about the axis of rotation D. On the outer
circumference of the drive gear 3, a camshaft gear 26 is arranged
seated on the ring flange the drive gear 3 around the double ball
bearing 9 and protrudes into the groove 22 at the outer side of the
drive gear 3. The camshaft gear wheel 26 connected via a timing
chain 27 is in rotational angle-fixed manner to the crankshaft (not
shown) of the internal combustion engine, i.e. coupled in a
crankshaft-fixed manner. An electric motor 28 is provided on the
power take-off shaft 2 of the actuating device 6 for adjusting the
rotational angle position between the drive gear 3 and the output
gear 4 of the transmission device 1, respectively between the
crankshaft-fixed camshaft gear wheel 26 and the camshaft 25 of the
internal combustion engine. This electric motor 28 can there
co-rotate with the rotational motion of the main drive via the
camshaft gear wheel 26, so that the relative rotational motion of
the main drive is merely accelerated or decelerated by the electric
motor 28 to achieve a desired adjustment of the angle of
rotation.
[0038] In an alternative inverted embodiment, the drive gear 3 and
the output gear 4 are configured as lantern elements 20 comprising
a plurality of pins 16 arranged concentric relative to the axis of
rotation D, where the transmitter disk 13 arranged eccentric
relative to the axis of rotation D comprises a first and a second
lantern toothing being arranged concentric to the transmitter disk
13. The lantern elements 20 of the drive gear 3 and the output gear
4 each in sections engage with the first and the second lantern
toothing of the transmitter disk 13 in order to move the drive gear
3 and the output gear 4 relative to each other. The transmitter
element 5 can there comprise two lantern gears of different
circumference connected to each other in a rotationally-fixed
manner eccentric to the axis of rotation D which by the eccentric
portion 10 of the actuating device 6 engage with the pins 16, being
arranged concentric to the axis of rotation D, of the lantern
elements 20 of the drive gear 3 and the output gear 4. The basic
mode of operation of this inverted configuration of a transmission
device adjustable in the angle of rotation does not differ from the
transmission device 1 illustrated in FIGS. 1 through 5 with an
eccentrically revolving lantern element 20.
[0039] The function and the mode of operation of a transmission
device 1 adjustable in the angle of rotation, or respectively a cam
phaser 24, are illustrated in detail below.
[0040] For transmission of a rotational motion of a main drive, for
example the motion of a crankshaft (not shown) of an internal
combustion engine, the camshaft gear wheel 26 and the drive gear 3
fixedly connected thereto is during operation by use of the
transmission device 1 via the lantern element 20 in sections being
in engagement with the drive gear 3 and the output gear 4 coupled
to the output gear 4 and from there connected to the camshaft
25.
[0041] As clearly visible in FIG. 1, simultaneous engagement in
sections of the pins 16 protruding at the first and the second face
sides 14, 15 of the transmitter disk 13 with the lantern gear 18 of
the drive gear 3 and the lantern gear 19 of the output gear 4
enables direct transmission of the rotary motion of the main drive
of the drive gear 3 to the output gear 4.
[0042] For adjustment of the angle of rotation between the drive
gear 3 and the output gear 4, when used as a cam phaser 24,
respectively the adjustment of the angle of rotation between the
camshaft gear wheel 26 attached between the drive gear 3 and the
camshaft 25 arranged on the output gear 4, an additional rotational
motion is via the power take-off shaft 2 forced upon the lantern
element 20 by the eccentric portion 10. For this purpose, a
suitable drive is attached to the power take-off shaft 2, commonly
a traveling electric motor 28.
[0043] The transmitter disk 13 of the lantern element 20 mounted
eccentric relative to the gear axis D on a ball bearing 12 is via
the rotational motion of the circular eccentric portion 10 being
eccentric relative to the axis of rotation D of the power take-off
shaft 2 also activated to perform a wobbling motion about the gear
axis of rotation D.
[0044] The ball bearing 12 positioned between the eccentric portion
10 and the transmitter disk 13 on the eccentric bearing seat 11
there allows a low-friction relative motion between the lantern
element 20 and the eccentric portion 10. The eccentrically arranged
region of the circular eccentric portion 10 via the ball bearing 12
presses the transmitter disk 13 or the pins 16 protruding at the
first and the second face side 14, 15, respectively, into the
toothing of the lantern gears 18, 19 of the drive gear 3 and the
output gear 4, so that, with a revolution of the eccentric portion
10, the lantern element 20 rolls over the entire circumference on
the lantern gears 18 and 19. In this, the drive gear 3 and the
output gear 4 move relative to the lantern element 20 each offset
by the difference between the number of pins 16 on the first and
the second face side 14, 15 of the transmitter disk 13 and the
number of the tooth gaps of the associated lantern gears 18, 19.
While on the one side, see Fig. below 1, the pins 16 protruding
from the first and the second face side 14, 15 are in engagement
with the associated lantern gears 18, 19 of the drive gear 3 or the
output gear 4, respectively, a gap S amounting to approximately
twice the eccentricity e arises between the pin 16 and the Lantern
gears 18, 19 on the opposite side of the transmitter disk 13 being
spaced by the eccentricity e from the axis of rotation D. Gap S
prevents overlap of the pins 16 with the protruding teeth of the
lantern gears 18, 19, thereby allowing eccentric revolution of the
lantern element 20 between the drive gear 3 and the output gear
4.
[0045] When adjusting the angle of rotation between the drive gear
3 and the output gear 4 of the transmission device 1, respectively
adjustment of the angle of rotation between the camshaft gear wheel
26 and the camshaft 25 of the cam phaser 24, the co-rotating rotor
of the electric motor 28, in the event of use of a co-rotating
electric motor 28, arranged on the power take-off shaft 2 is
accelerated or decelerated so that the position of the eccentric
portion 10 and thereby of the transmitter disk 13 changes relative
to the drive gear 3 and the output gear 4. During mere transmission
of the main drive to the drive gear 3, i.e. during mere
transmission of the rotational motion of the crankshaft-fixed
camshaft gear wheel 26 to the camshaft 25 on the other hand, the
relative position of the drive gear 3 and the output gear 4
relative to each other does not change.
[0046] When adjusting the angle between of rotation between the
drive gear 3 and the output gear 4 of the transmission device 1,
respectively adjustment of the angle of rotation between the
camshaft gear wheel 26 and the camshaft 25 of the cam phaser 24,
the co-rotating rotor of the electric motor 28, in the event of use
of a co-rotating electric motor 28, arranged on the power take-off
shaft 2 is accelerated or decelerated so that the position of the
eccentric portion 10 and thereby of the transmitter disk 13 changes
relative to the drive gear 3 and the output gear 4. During mere
transmission of the main drive to the drive gear 3, i.e. during the
mere transmission of the rotational motion of the crankshaft-fixed
camshaft gear wheel 26 to the camshaft 25 on the other hand, the
relative position of the drive gear 3 and the output gear 4
relative to each other does not change. During a motion of the
transmitter disk 13, the pins 16 of the lantern element 20 roll
around the lantern gears 18, 19, whereby the drive gear 3 and the
output gear 4 move relative to each other. The reduction ratio of
the lantern element 20 from the lantern gear 18 of the drive gear 3
to the lantern gear 19 of the output gear 4 results from the
different rolling distance of the lantern element 20 on the lantern
gear 18 as compared to the lantern gear 19.
[0047] The transmission device 1 according to the invention shown
in the embodiments in FIGS. 1 through 5 comprises, for example, 60
pins 16 on the eccentrically revolving lantern element 20 on the
first face side 14, and slightly less on the second face side 15,
namely 56 pins 16. The lantern gears 18, 19 associated with these
rows of pins 16 and disposed in the inner spaces formed by the pins
arranged in a circular manner concentric relative to the eccentric
axis E comprise a number of teeth which is each smaller by 1. For
the partial transmission ratio between the drive gear 3 and the
lantern element 20 as well as between the output gear 4 and the
lantern element 20, transmission ratios therefore arise of about
1:60 and 1:56, so that an overall transmission ratio of about 1:820
results. Compared to this subtractive interconnection of these two
partial transmission ratios, an overall transmission ratio of
approximately 1;30 would be obtained with only one ring of pins on
the front side during engagement of one of the lantern gears 18 or
19 as a ring gear from the outside and one from the inside with the
lantern element 20. Accordingly, gear mechanisms with very high
reduction ratios can be realized with the transmission device 1
according to the invention.
LIST OF REFERENCE NUMERALS
[0048] 1: transmission device [0049] 2: power take-off shaft [0050]
3: drive shaft [0051] 4: output shaft [0052] 5: transmitter element
[0053] 6: actuating device [0054] 7: drive bearing seat [0055] 8:
output bearing seat [0056] 9: double ball bearing [0057] 10:
eccentric portion [0058] 11: eccentric bearing seat [0059] 12: ball
bearing [0060] 13: transmitter disk [0061] 14: first face side
[0062] 15: second face side [0063] 16: pins [0064] 17: bores [0065]
18: lantern gear [0066] 19: lantern gear [0067] 20: lantern element
[0068] 21: shaft stub [0069] 22: groove [0070] 23: groove [0071]
24: cam phaser [0072] 25: camshaft [0073] 26: camshaft gear wheel
[0074] 27: timing chain [0075] 28: electric motor
[0076] D: axis of rotation [0077] E: eccentric axis [0078] S: gape
[0079] .epsilon.: eccentricity
* * * * *