U.S. patent application number 12/389854 was filed with the patent office on 2009-08-27 for cam phase adjuster with a plurality of springs.
This patent application is currently assigned to SCHAEFFLER KG. Invention is credited to Gregory MULLER, Roger MYER, Jesse MYERS.
Application Number | 20090211549 12/389854 |
Document ID | / |
Family ID | 40997090 |
Filed Date | 2009-08-27 |
United States Patent
Application |
20090211549 |
Kind Code |
A1 |
MYERS; Jesse ; et
al. |
August 27, 2009 |
CAM PHASE ADJUSTER WITH A PLURALITY OF SPRINGS
Abstract
The camshaft adjuster is a plurality of return springs which are
in parallel to one another in a spring.
Inventors: |
MYERS; Jesse; (WATERFORD,
MI) ; MULLER; Gregory; (TROY, MI) ; MYER;
Roger; (BRIGHTON, MI) |
Correspondence
Address: |
LUCAS & MERCANTI, LLP
475 PARK AVENUE SOUTH, 15TH FLOOR
NEW YORK
NY
10016
US
|
Assignee: |
SCHAEFFLER KG
Herzogenaurach
DE
|
Family ID: |
40997090 |
Appl. No.: |
12/389854 |
Filed: |
February 20, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61030303 |
Feb 21, 2008 |
|
|
|
Current U.S.
Class: |
123/90.17 ;
464/160 |
Current CPC
Class: |
F01L 2001/34483
20130101; F01L 2820/041 20130101; F01L 2820/02 20130101; F01L
1/3442 20130101; F01L 2001/34469 20130101 |
Class at
Publication: |
123/90.17 ;
464/160 |
International
Class: |
F01L 1/344 20060101
F01L001/344 |
Claims
1. A camshaft phase adjuster comprising: a stator and a rotor
adjustable to the stator in a circumferential direction by a
pressure medium; at least one spring chamber proximately located
adjacent to the stator and the rotor; and a plurality of return
springs proximately arranged in the spring chamber, each of the
springs having a rotor connecting end for connecting to the rotor
and a stator connecting end for connecting to the stator, the
return springs configured to rotate the rotor relative to the
stator into an initial position absent pressure from the pressure
medium.
2. The adjuster of claim 1, wherein the spring chamber is axially
adjacent to the stator and the rotor.
3. The adjuster of claim 1, wherein the plurality of return springs
are arranged axially adjacent to one another in the spring
chamber.
4. The adjuster of claim 1, wherein the plurality of return springs
is 2 or more.
5. The adjuster of claim 1, wherein the return springs are flat,
spiral springs.
6. The adjuster of claim 1, wherein each of the return springs has
an equal strength.
7. The adjuster of claim 2, wherein the plurality of return springs
is 2 to 4.
8. The adjuster of claim 1, wherein the return springs are not of
equal strength.
Description
FIELD OF THE INVENTION
[0001] This Invention relates to cam phase adjusters used for
adjusting the angular relative position of the camshaft in relation
to the crankshaft and, more particularly, to vane-type camshaft
phasers having a stator and a rotor.
BACKGROUND OF THE INVENTION
[0002] Vane-type phasers are conventional devices used especially
in motor vehicles in order to adjust the angular position of a
camshaft in relation to the crankshaft of the internal combustion
engine. The device uses a stator and a rotor to adjust the angular
position of the camshaft in relation to the crankshaft. The stator
rotates on the camshaft and is rotated by a belt or chain from the
crankshaft. The rotor is fixed to the camshaft. The stator has a
plurality of pressure chambers, each of which are divided by the
vanes of the rotor. By applying a pressure medium, typically oil,
into the pressure chamber on either side of the rotor vane, the
angular relationship between the stator and the rotor is changed
and, hence, the relative angular position between the crankshaft
and the camshaft is adjusted.
[0003] Typically, a return spring, such as a flat spiral spring, is
used to return the rotor to an initial rest position when the
engine is turned off. One of the problems is that when the overall
camshaft drag torque is high, a single return spring is not
adequate or is too slow. In certain cases, hydraulic pressure is
used to assist the return spring, however, hydraulic pressure can
detract from the efficiency of the engine.
OBJECT OF THE INVENTION
[0004] It is the object of the present Invention to provide a
spring design which provides an adequate level of return spring
compensation for a phaser so as to have consistently balanced
shifting speeds in the advanced and retard timing directions. It is
also the object of the present Invention to provide a reliable
unlocking of the locking mechanism of the phaser in locked
position. It is furthermore, the object of the present Invention to
accomplish high return spring torques in a set area of space.
[0005] These and other objects of the present Invention will be
more readily understood by reference to the following description
of the Invention.
SUMMARY OF THE INVENTION
[0006] The present Invention obtains these objects by an improved
spring design in which a plurality of return springs is used.
Furthermore, robustness and durability of the phaser is also
improved by employing a plurality of return springs in the phaser.
The overall working stress on each of the individual return springs
can be lowered because of the plurality of return springs and
therefore increase the factor of safety for the return springs as a
whole.
[0007] More specifically, a plurality of return springs is
assembled in parallel in the camshaft phaser. The plurality of
parallel return springs provide a high return spring compensation
when the overall camshaft drag torque is at levels which are too
high to be compensated for by a single spring. The total summation
of torque from the plurality of return springs is suitably higher
than the overall camshaft drag torque.
[0008] Broadly, the present Invention can be defined as a camshaft
phaser adjuster comprising:
[0009] a stator and a rotor adjustable to the stator in a
circumferential direction by a pressure medium;
[0010] at least one spring chamber proximately located adjacent to
the stator and the rotor; and
[0011] a plurality of return springs proximately arranged in the
spring chamber, each of the springs having a rotor connecting end
for connecting to the rotor and a stator connecting end for
connecting to the stator, the return springs configured to rotate
the rotor relative to the stator into an initial position absent
pressure from the pressure medium.
[0012] In the preferred embodiment, the spring chamber is axially
adjacent to the stator and rotor and the plurality of return
springs are arranged axially adjacent to one another in the spring
camber. Multiple spring cambers and other spring arrangements such
as co-axial return springs will occur to those skilled in the art
and are within the scope of the present invention.
[0013] Preferably, the number of return springs is two or more;
and, more preferably, the number of return springs is two to
four.
[0014] Suitably, the return springs are flat spiral springs. Each
of the springs preferably has equal strength, however, equal
strength springs are not required. There could be a scenario where
different strengths are used. IE. 3 Nm+5 Nm=8 Nm or 4 Nm.times.2=8
Nm.
[0015] One of the unique aspects of the present Invention is the
fact that each of the return springs is identical in both strength
and size. This leads to a balance of the torque and a cost savings
and simplicity because of only one type of spring component part is
used for several different outputs for different assemblies.
[0016] In order to allow for the use of a plurality of return
springs, the support(s) for the springs are increased in length and
the spring chamber, which is defined by the spring outer housing,
is increased or deepened to accommodate the side-by-side axial
arrangement of the return springs.
[0017] When the phaser of the present Invention is assembled, all
return springs are wound simultaneously in the same manner as a
single return spring is wound. The multiple return springs supply
adequate torque to counteract the high camshaft drag torque of the
engine. This yields balanced shifting speeds and excellent phaser
unlocking behavior. Balanced shifting velocities and excellent
unlocking behavior is just one of the unique advantages of the
present Invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] These and other aspects of the present Invention may be more
readily understood by reference to one or more of the following
drawings which are herein presented for purposes of illustration
only.
[0019] FIG. 1 illustrates a cross section of the camshaft phase
adjuster of the present Invention;
[0020] FIG. 2 illustrates an exploded view of the adjuster;
[0021] FIG. 3 illustrates a cutaway view of the adjuster;
[0022] FIG. 4 illustrates an axial view of the adjuster;
[0023] FIG. 5 illustrates a cross section of an alternate
embodiment of the camshaft phase adjuster of the present Invention;
and
[0024] FIG. 6 illustrates an exploded view of a further alternate
embodiment of the camshaft phase adjuster of the present
Invention.
DETAILED DESCRIPTION OF THE DRAWINGS
[0025] FIGS. 1 and 2 illustrate a phase adjuster 10 with stator 12
fixedly mounted inside sprocket 14, with locking cover 16 and
sealing cover 17 sealing stator pressure chambers 20. Lugs 18 of
stator 12 divides stator 12 into pressure chambers 20 in a
conventional manner. Stator 12 is fixed to drive wheel 14 and drive
wheel 14 is driven by the crankshaft of the engine.
[0026] Rotor 22 is fixed to camshaft 23 as shown in FIGS. 3 and 4.
Rotor 22 has vanes 24 which reside in pressure chamber 20. Pressure
chamber 20 is divided by vanes 24 into one half 26 and another half
28. Pressure medium is pumped into one of the half chambers 26 or
28 in order to rotate the rotor with respect to the stator. Such
operation is conventional.
[0027] Spring chamber 30 is defined by trigger wheel 31 which acts
as an outer housing and locking cover 16. Drive screws 11 fixes
housing 31 to rotor 22.
[0028] Arranged adjacent to one another in spring chamber 30 are
spiral springs 34 and 36. Each spiral springs 34 and 36 has a rotor
connecting end 38 and 40, respectively, and a stator connecting end
42 and 44, respectively. Each of the spring ends is, in turn,
connected to a respective rotor stop 46, 48 and a stator stop 50,
52.
[0029] An alternate embodiment is illustrated in FIG. 5 wherein the
phase adjuster 54 is comprised of spring chamber 56. Arranged
concentric to one another in spring chamber 56 are inner spring 58
and outer spring 60. Preferably, inner spring 58 and outer spring
60 are flat spiral springs; although the invention does not
preclude inner spring 58 and outer spring 60 made of different
springs such as coil springs.
[0030] A further alternate embodiment is illustrated in FIG. 6
wherein the phase adjuster 62 is comprised of left spring chamber
64 and right spring chamber 66. Arranged in spring chamber 64 is
left spring 68 and arranged in spring chamber 66 is right spring
70. Preferably, left spring 68 and right spring 70 are flat spiral
springs; although the invention does not preclude left spring 68
and right spring 70 made of different springs such as coil
springs.
REFERENCE CHARACTERS
[0031] 10. Phase adjuster [0032] 11. Drive screws [0033] 12. Stator
[0034] 14. Sprocket [0035] 16. Locking cover [0036] 17. Sealing
cover [0037] 18. Lugs of stator [0038] 20. Pressure chambers [0039]
22. Rotor [0040] 23. Camshaft [0041] 24. Vanes of rotor [0042] 26.
One half pressure chamber 20 [0043] 28. Other half pressure chamber
20 [0044] 30. Spring chamber [0045] 31. Trigger wheel [0046] 32.
Spring support bolt [0047] 34. Spiral spring [0048] 36. Spiral
spring [0049] 38. Rotor connecting end [0050] 40. Rotor connecting
end [0051] 42. Stator connecting end [0052] 44. Stator connecting
end [0053] 46. Rotor stop [0054] 48. Rotor stop [0055] 50. Stator
stop [0056] 52. Stator stop [0057] 54. Phase adjuster [0058] 56.
Spring chamber [0059] 58. Inner spring [0060] 60. Outer spring
[0061] 62. Phase adjuster [0062] 64. Left spring chamber [0063] 66.
Right spring chamber [0064] 68. Left spring [0065] 70. Right
spring
* * * * *