U.S. patent application number 10/578599 was filed with the patent office on 2007-04-05 for adjustment device for adjusting the relative rotational angle position of a camshaft in relation to a crankshaft of an internal combustion engine.
Invention is credited to Jonathan Heywood, Jens Schafer, Martin Steigerwald.
Application Number | 20070074692 10/578599 |
Document ID | / |
Family ID | 34559506 |
Filed Date | 2007-04-05 |
United States Patent
Application |
20070074692 |
Kind Code |
A1 |
Schafer; Jens ; et
al. |
April 5, 2007 |
Adjustment device for adjusting the relative rotational angle
position of a camshaft in relation to a crankshaft of an internal
combustion engine
Abstract
An adjustment device (1) for adjusting the relative rotational
angle position of a camshaft (2) in relation to a crankshaft of an
internal combustion engine is provided, with the device having an
adjustment mechanism (3), which is embodied as a triple-shaft
transmission and provided with an input part (4) fixed to the
crankshaft, an output part fixed to the camshaft, and an adjusting
shaft (7) connected to an adjusting motor shaft (5) of an adjusting
motor (6). The motor (6) is provided as an electric motor and is
spatially separated from the adjusting shaft (7), and the torque
produced thereby is transmitted to the adjusting shaft (7), either
mechanically via a flexible shaft (8), pneumatically via a
compressor (9) operating a pneumatic motor (13) using pressurized
air, or hydraulically via a hydraulic motor (16) and a pump (14)
providing the hydraulic medium. The adjusting motor (6) can also be
arranged parallel to the adjusting shaft (7) or radially in
relation thereto, and the torque is transmitted by toothed gearing
or a secondary drive.
Inventors: |
Schafer; Jens;
(Herzogenaurach, DE) ; Steigerwald; Martin;
(Erlangen, DE) ; Heywood; Jonathan; (Pettstadt,
DE) |
Correspondence
Address: |
VOLPE AND KOENIG, P.C.
UNITED PLAZA, SUITE 1600
30 SOUTH 17TH STREET
PHILADELPHIA
PA
19103
US
|
Family ID: |
34559506 |
Appl. No.: |
10/578599 |
Filed: |
October 6, 2004 |
PCT Filed: |
October 6, 2004 |
PCT NO: |
PCT/EP04/11151 |
371 Date: |
May 8, 2006 |
Current U.S.
Class: |
123/90.17 ;
123/90.15 |
Current CPC
Class: |
F01L 1/344 20130101;
F01L 1/34 20130101; F01L 1/352 20130101; F02N 7/00 20130101; F01L
1/46 20130101 |
Class at
Publication: |
123/090.17 ;
123/090.15 |
International
Class: |
F01L 1/34 20060101
F01L001/34 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 8, 2003 |
DE |
103 52 255.7 |
Claims
1. Adjustment device (1) for adjusting the relative rotational
angle position of a camshaft (2) in relation to a crankshaft of an
internal combustion engine, the device comprising an adjustment
mechanism (3), which is provided as a triple-shaft transmission and
which has an input part (4) fixed to the crankshaft, an output part
fixed to the camshaft, and an adjustment shaft (7) connected to an
adjustment motor shaft (5) of an adjustment motor (6), wherein the
adjustment motor (6) comprises an electric motor and is placed
spatially separated from the adjustment shaft (7) and an adjustment
torque generated by the motor is transmitted mechanically by a
flexible shaft (8) to the adjustment shaft (7).
2. Adjustment device (1) for adjusting the relative rotational
angle position of a camshaft (2) in relation to a crankshaft of an
internal combustion engine, the device comprising an adjustment
mechanism (3), which is provided as a triple-shaft transmission and
which has an input part (4) fixed to the crankshaft, an output part
fixed to the camshaft, and an adjustment shaft (7) connected to an
adjustment motor shaft (5) of an adjustment motor (6), wherein the
adjustment mechanism (3) is driven with a pneumatic motor (13),
wherein a compressor (9) driven by an electric motor (6) supplies
compressed air required for the pneumatic motor.
3. Device according to claim 2, wherein a directional control valve
(12) that controls a rotational direction of the pneumatic motor
(13) is arranged between the compressor (9) and the pneumatic motor
(13).
4. Device according to claim 3, wherein a non-return valve (11) is
arranged between the compressor (9) and the directional control
valve (12).
5. Device according to claim 4, wherein a pressurize reservoir (10)
is arranged between the direction control valve (12) and the
non-return valve (11).
6. Adjustment device (1) for adjusting the relative rotational
angle position of a camshaft (2) in relation to a crankshaft of an
internal combustion engine, the device comprising an adjustment
mechanism (3), which is provided as a triple-shaft transmission and
which has an input part (4) fixed to the crankshaft, an output part
fixed to the camshaft, and an adjustment shaft (7) connected to an
adjustment motor shaft (5) of an adjustment motor (6), wherein the
adjustment mechanism (3) is driven with a hydraulic motor (16), and
a pump (14) that supplies hydraulic fluid required for the
hydraulic motor is driven by an electric motor (6).
7. Device according to claim 6, wherein a direction control valve
(12'') that controls a rotational direction of the hydraulic motor
is arranged between the pump (14) and the hydraulic motor (16).
8. Device according to claim 7, wherein a non-return valve (11'')
is arranged between the pump (14) and the directional control valve
(12'').
9. Device according to claim 8, wherein a pressurized hydraulic
accumulator (15) is arranged between the directional control valve
(12'') and the non-return valve (11'').
10. Adjustment device (1) for adjusting the relative rotational
angle position of a camshaft (2) in relation to a crankshaft of an
internal combustion engine, the device comprising an adjustment
mechanism (3), which is embodied as a triple-shaft transmission and
which has an input part (4) fixed to the crankshaft, an output part
fixed to the camshaft, and an adjustment shaft (7) connected to an
adjustment motor shaft (5) of an adjustment motor (6), wherein the
adjustment motor (6) comprises an electric motor and is arranged
radially relative to the camshaft (2).
11. Device according to claim 10, wherein a toothed gear (17) is
arranged between the electric motor and the camshaft, wherein an
adjustment torque generated by the electric motor is transmitted
mechanically via the toothed gear (17) to the adjustment shaft
(7).
12. Device according to claim 11, wherein the toothed gear (17)
comprises a bevel gear pair, a worm gear pair, or a spiral gear
pair.
13. Device according to claim 11, wherein the transmission ratio of
the toothed gear is 1:1.
14. Adjustment device (1) for adjusting the relative rotational
angle position of a camshaft (2) in relation to a crankshaft of an
internal combustion engine, the device comprising an adjustment
mechanism (3), which is provided as a triple-shaft transmission and
which has an input part (4) fixed to the crankshaft, an output part
fixed to the camshaft, and an adjustment shaft (7) connected to an
adjustment motor shaft (5) of an adjustment motor (6), wherein the
adjustment motor (6) comprises an electric motor and is arranged
parallel to the camshaft (2) and an adjustment torque generated by
the motor is transmitted via a secondary drive (18) to the
adjustment shaft (7).
15. Device according to claim 14, wherein the secondary drive (18)
comprises a belt drive, a chain drive, a cardan drive, or an
additional spur gear stage.
Description
BACKGROUND
[0001] The invention relates to an adjustment device for adjusting
the relative rotational angle position of a camshaft in relation to
a crankshaft of an internal combustion engine, with the device
comprising an adjustment mechanism, which is embodied as a
triple-shaft transmission and provided with an input part fixed to
the crankshaft, an output part fixed to the camshaft, and an
adjusting shaft connected to an adjusting motor shaft of an
adjusting motor.
[0002] In modern internal combustion engines, a camshaft adjuster
is used for varying the timing of gas-exchange valves, whereby an
improvement in consumption and output is achieved over the entire
load and rpm range. It is known that camshaft adjusters can be
actuated hydraulically. Conventional, hydraulically actuated
camshaft adjusters (axial piston adjusters, vane cells, pivoting
vanes and segmented vanes) have the advantage that the hydraulic
valve required for control does not have to be arranged directly
axially in front of the adjuster, but instead can be mounted
off-center at a position, where sufficient installation space is
available for the valve. The oil is led via bore holes in the
cylinder head to the adjuster. Therefore, hydraulic camshaft
adjusters are built very short and can also be installed under
tight installation conditions. Because the adjustment is realized
by the pressure of motor oil in conventional, hydraulic camshaft
adjusters, the function of the camshaft adjuster is very dependent
on the temperature of the motor oil. At low temperatures and thus
thick oil, the camshaft adjuster responds not at all or only
sluggishly due to the low volume flow. At high temperatures and
thus very thin oil, a high pressure is not established, which is
why a slow adjustment is also realized under this condition. In
addition, the oil pressure and thus the function of the camshaft
adjuster depends on the rpm of the internal combustion engine.
[0003] These disadvantages do not appear in an electric camshaft
adjuster built from an electric motor and adjustment mechanism.
However, as provided, for example, from the publication DE 4110195
A1, conventionally this adjuster is embodied such that the electric
motor is arranged axially in front of the adjustment mechanism and
thus requires a large amount of axial installation space.
SUMMARY
[0004] Therefore, the invention is based on the objective of
creating an adjustment device for adjusting the rotational angle
position of a camshaft in relation to a crankshaft of an internal
combustion engine, with the device combining the advantages of the
electric camshaft adjuster with the advantage of a very short
construction space similar to the hydraulic devices.
[0005] According to the invention, for an internal combustion
engine with the features of the preamble of claims 1, 2, 6, 10, and
14, the objective is met in that the adjusting motor is provided as
an electric motor. It is either placed spatially separated from the
adjustment mechanism, wherein the adjusting torque generated by it
either is transmitted mechanically by a flexible shaft to the
adjustment mechanism or drives a compressor, whose compressed air
acts on the adjustment mechanism via a pneumatic motor, or drives a
pump for hydraulic fluid, which acts on the adjustment mechanism
via a hydraulic motor. Alternatively, it is arranged radial or
parallel in relation to the camshaft, and the adjusting torque
generated by the electric motor is transmitted via a toothed gear
or a secondary drive to the adjusting shaft.
[0006] In the first case, the electric motor can be placed
arbitrarily. The adjusting torque generated by it is transmitted by
the flexible shaft. The flexible shaft can be variably adapted-like
a speedometer shaft-to the installation space and here transmits
the rotation and the torque from the electric motor shaft to the
adjusting shaft of the adjustment mechanism. Because the efficiency
of this transmission is very high, the spatial separation of
adjustment mechanism and electric motor can be realized. In order
not to load the power balance of the internal combustion engine
surroundings too much, it has proven especially advantageous to use
a low-output, but quickly rotating electric motor. Its torque is
then transmitted via the flexible shaft to the adjusting shaft of
the adjustment mechanism, whose transmission ratio preferably lies
in the range of 1:50 to 1:120.
[0007] In the second case, the adjustment mechanism is not
connected directly to an electric motor, but instead to a pneumatic
motor. The essential advantage of the pneumatic motor is that the
motor can be built with a significantly shorter axial size than an
electric motor used directly for adjusting or can be partially
integrated into the installation space of the transmission. The
rotational direction of the pneumatic motor is controlled by a
directional control valve, which draws the needed compressed air
from a compressor that is driven, on its side, by an electric
motor. It is advantageous to use a directional control valve, which
is in the closed position when not actuated. Both the compressor
and also the electric motor are arranged off-center relative to the
adjustment mechanism at a position where there is sufficient
installation space. For preventing pressure fluctuations during
operation, a pressurize reservoir, which equalizes possible
pressure fluctuations, is arranged between the compressor and
directional control valve. This pressure reservoir can then also be
placed arbitrarily. Another advantage of the pressurize reservoir
is that even when the internal combustion engine is started, there
is sufficient pressure for operating the pneumatic motor, even if
sufficient pressure had not yet been generated by the compressor.
In particular, the cold-start behavior of the internal combustion
engine is improved. So that the compressed air does not bleed out
of the pressurize reservoir when the electric motor is idling,
there is a non-return valve between the reservoir and the
compressor.
[0008] The compressor can also be driven by a belt of the internal
combustion engine instead of by an electric motor. However, then
the compressor rpm is dependent on the rpm of the internal
combustion engine, while for the use of an electric motor, the
compressor can always be operated independent of the internal
combustion engine. As an alternative, when driven with a belt, a
motor with variable volume displacement, e.g., a double-stroke
vane-cell motor, can also be used.
[0009] In the third case, the adjustment is realized by a hydraulic
motor. The construction and operation of the system correspond to
that of the electric, pneumatic system, except that as the medium,
a fluid is used instead of air. The directional control valve can
be represented by a proportional valve, two 3/2 directional valves,
four 2/2 directional valve, or by a controllable pump and a 4/2
directional valve in switch or proportional configuration. The
advantage in this system lies in that higher pressures can be
generated. A disadvantage is the somewhat higher expense in terms
of the recirculation of the fluid. As fluid, the oil of the motor
oil cycle, but also a different, additional fluid can be used,
which is not exposed to such strong operating temperature
fluctuations. Due to the pressurized hydraulic accumulator, the
pressure is already ready at the start phase of the internal
combustion engine. Thus, the hydraulic motor can be operated more
reliably than a hydraulic device for rotational angle
adjustment.
[0010] If installation space is available radial to the adjustment
shaft, it is also possible to embody the adjustment motor as an
electric motor and to arrange it radially. Its adjusting torque is
driven via a toothed gear, whose transmission ratio is preferably
1:1. Here, for example, bevel gear pairs, worm gear pairs, or
spiral gear pairs are conceivable as configurations of the
mechanism. The advantage of these systems is that compressed air
units are neither necessary nor do they have to be integrated into
a fluid cycle. The system is thus simpler in construction,
not-sensitive to breaks in seals, and is thus more
maintenance-friendly.
[0011] As a fifth solution, it is provided to arrange the
adjustment motor parallel to the adjustment mechanism. The torque
transmission from the adjustment motor shaft to the adjustment
mechanism is then realized by means of a secondary drive. This
secondary drive can be formed, for example, as a belt drive, a
chain drive, a cardan drive, or as an additional spur gear stage.
The advantages of this arrangement are the same as in the radial
electric motor: compressed air units are neither necessary nor have
to be integrated into a fluid cycle. The system is thus simpler in
construction, not sensitive to breaks in seals, and is thus more
maintenance-friendly.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The invention is explained in more detail below and is shown
schematically in the associated drawings.
[0013] Shown are:
[0014] FIG. 1 a schematic representation of an electromechanical
system with electric motor, flexible shaft, adjustment mechanism,
and camshaft;
[0015] FIG. 2 a schematic representation of an electric, pneumatic
system with electric motor, compressor, non-return valve,
pressurize reservoir, directional control valve, pneumatic motor,
adjustment mechanism, and camshaft;
[0016] FIG. 3 a schematic representation of an electric, hydraulic
system with electric motor, pump, non-return valve, pressurized
container, directional control valve, hydraulic motor, adjustment
mechanism, and camshaft;
[0017] FIG. 4 a cross-sectional representation of an
electromechanical system with radial adjustment motor shaft;
[0018] FIG. 5 a cross section of an electromechanical system with
parallel adjustment motor.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0019] From FIG. 1 emerges the principle arrangement of the
components of an adjustment device 1 for electromechanical
adjustment of the relative rotational angle position of a camshaft
2 relative to a crankshaft (not shown) of an internal combustion
engine with an adjustment mechanism 3, which is embodied as a
triple-shaft transmission and which has an input part 4 fixed to
the crankshaft, an output part fixed to the camshaft, and an
adjustment shaft 7 connected to an adjustment motor shaft 5 of an
electric motor 6. The adjusting torque of the adjustment motor
shaft 5 generated by the electric motor 6 is transmitted
mechanically from a flexible shaft 8 to the adjustment shaft 7.
Therefore, spatial separation of the electric motor 6 and the
adjustment mechanism 3 is possible. The illustrated spatial
position of the components of the adjustment device 1 is to be
considered only as an example, because the flexible shaft 8 can be
adapted to the installation space.
[0020] FIG. 2 shows the principle arrangement of the components of
an adjustment device 1' for electromechanical adjustment of the
relative rotational angle position of a camshaft 2' relative to a
crankshaft (not shown) of an internal combustion engine with an
adjustment mechanism 3', which is embodied as a triple-shaft
transmission and which has an input part 4' fixed to the
crankshaft, an output part fixed to the camshaft, and an adjustment
shaft 7' driven by a pneumatic motor 13. The adjustment torque of
the adjustment motor shaft 5' generated by an electric motor 6'
drives a compressor 9, which provides compressed air to a
pressurize reservoir 10. Here, a non-return valve 11 is arranged
between the pressurize reservoir 10 and the compressor 9, so that
compressed air is already available when the internal combustion
engine is initially started and the compressor is not yet running.
The pressurize reservoir 10 is connected via compressed air with a
directional control valve 12 in a switching or proportional
configuration, which is embodied, for example, as a 4/3 directional
valve with two magnetic coils. The directional control valve 12
controls a pneumatic motor 13, which is fixed in rotation with the
adjustment shaft 7' of the adjustment mechanism 3'.
[0021] FIG. 3 shows the principle arrangement of the components of
an adjustment device 1'' for electromechanical adjustment of the
relative rotational angle position of a camshaft 2'' in relation to
a crankshaft (not shown) of an internal combustion engine with an
adjustment mechanism 3'', which is embodied as a triple-shaft
transmission and which has an input part 4'' fixed to the
crankshaft, an output part fixed to the camshaft, and an adjustment
shaft 7'' driven by a hydraulic motor 16. The adjustment torque of
the adjustment motor shaft 5'' generated by an electric motor 6''
drives a pump, which pumps fluid into a pressurized hydraulic
accumulator 15. Between the hydraulic accumulator 15 and pump 14
there is a non-return valve 11', so that pressurized fluid is
already available when the internal combustion engine is started
and the pump is not yet running. The hydraulic accumulator 15 is
connected to a direction control valve 12'', which is embodied, for
example, as a proportional valve. The direction control valve 12''
controls a hydraulic motor 16, which is locked in rotation with the
adjustment shaft 7'' of the adjustment mechanism 3''.
[0022] FIG. 4 shows a cross section through the essential
components of an adjustment device 1 (FIG. 1) for electromechanical
adjustment of the relative rotational angle position of a camshaft
2 (FIG. 1) in relation to a crankshaft (not shown) of an internal
combustion engine with an adjustment mechanism 3 (FIG. 1), which is
embodied as a triple-shaft transmission and which has an input part
fixed to the crankshaft, an output part fixed to the camshaft, and
an adjustment shaft 7 connected to an adjustment motor shaft 5 of
an electric motor 6, wherein the electric motor 6 is arranged
radially. The adjustment torque of the adjustment motor shaft 5
generated by the electric motor 6 is transmitted mechanically from
a toothed gear 17 to the adjustment shaft 7. Therefore, a radial
arrangement of electric motor 6 and adjustment shaft 7 is
possible.
[0023] FIG. 5 shows a cross section through the essential
components of an adjustment device 1 (FIG. 1) for electromechanical
adjustment of the relative rotational angle position of a camshaft
2 (FIG. 1) in relation to a crankshaft (not shown) of an internal
combustion engine with an adjustment mechanism 3 (FIG. 1), which is
embodied as a triple-shaft transmission and which has an input part
fixed to the crankshaft, a driven part fixed to the camshaft, and
an adjustment shaft 7 connected to an adjustment motor shaft 5 of
an electric motor 6, wherein the electric motor is arranged
parallel to the adjustment shaft. The adjustment torque of the
adjustment motor shaft 5 generated by the electric motor 6 is
transmitted mechanically from a secondary drive 18 to the
adjustment shaft 7. In FIG. 5, the secondary drive is illustrated
as a belt drive.
[0024] All of the disclosed solutions have the advantage that the
electric motor no longer has to be arranged in front of the
adjustment shaft, whereby a considerable shortening of the
installation space is possible. It can be placed arbitrarily in the
motor space relative to the electric motor, which also permits
greater freedoms for the shaping of the overall internal combustion
engine.
[0025] List of Reference Symbols [0026] 1, 1', 1'' Adjustment
device for electromechanical adjustment of the relative rotational
angle position of a camshaft in relation to a crankshaft of an
internal combustion engine [0027] 2, 2', 2'' Camshaft [0028] 3, 3',
3'' Adjustment mechanism [0029] 4, 4', 4'' Output part of the
adjustment mechanism fixed to the camshaft [0030] 5, 5', 5''
Adjustment motor shaft of the electric motor [0031] 6, 6', 6''
Electric motor [0032] 7, 7', 7'' Adjustment shaft [0033] 8 Flexible
shaft [0034] 9 Compressor [0035] 10 Pressurize reservoir [0036] 11,
11'' Non-return valve [0037] 12, 12'' Directional control valve
[0038] 13 Pneumatic motor [0039] 14 Pump [0040] 15 Hydraulic
accumulator [0041] 16 Hydraulic motor [0042] 17 Toothed gear [0043]
18 Secondary drive [0044] 19 Motor holder
* * * * *