The present disclosure relates to a camshaft phaser or adjuster for the inner camshaft of a concentric camshaft assembly, and in particular to a camshaft phaser or adjuster for adjusting the relative rotational angle position of an inner camshaft of a concentric camshaft assembly relative to the phase position of the outer camshaft and the crankshaft of an internal combustion engine.
Camshaft phasers that operate according to the vane-cell principle for use on single camshafts are known. These are described in publications by the assignee of the present invention, including U.S. Pat. No. 6,805,080, which is incorporated herein by reference as if fully set forth. These work well in connection with DOHC engines where all the intake or exhaust cam lobes are located on separately located intake and exhaust camshafts.
It has also been known to use camshaft phasers in connection with concentric camshaft assemblies for controlling the phase position of the inner camshaft, the outer camshaft or both. One such arrangement is described in DE 10 2006 024 793 A1. This publication discloses a dual phasing system for a concentric camshaft assembly which includes two camshaft phasers which are located at the front of an engine that are axially spaced adjacent to one another. These two camshaft phasers allow independent control of the rotation angle of the outer and inner co-axial camshafts relative to the crankshaft in order to allow separate adjustment of the timing of the intake and the exhaust valves of the internal combustion engine. However, this arrangement provides additional complexity which is often not required to obtain many of the benefits of adjusting either the inner or the outer camshafts of a concentric camshaft assembly without the need for adjusting both.
It would be desirable to provide a camshaft phaser for a concentric camshaft assembly that allows for phasing of either the intake or exhaust lobes of a camshaft in which the drive load from the timing chain or belt extending from the crankshaft to the timing gear or timing belt pulley of the concentric camshaft arrangement is transmitted to the outer shaft of the concentric camshaft.
According to aspects illustrated herein, there is provided a camshaft phaser, including:
an inner rotor with radially outwardly extending vanes which is connected to the inner camshaft; a stator having radially inwardly directed projections which contact the outer surface of the rotor and form working spaces into which the vanes extend, the vanes divide the working spaces into first and second sets of pressure chambers which can be pressurized with a hydraulic medium in order to rotate the rotor in an advancing or retarding direction; a front cover connected to a front side of the assembly defining a front side of the pressure chambers; and a rear cover connected to the rear side of the assembly defining a rear side of the pressure chambers, having first and second protrusions directed toward and meshing with complementary first and second indentations on an outer camshaft.
According to further aspects illustrated herein, the first and second protrusions are different widths. According to yet further aspects illustrated herein, the first, second and third protrusions are separated by different circumferential distances and mesh with first, second and third indentations in an outer camshaft.
Various embodiments are disclosed, by way of example only, with reference to the accompanying schematic drawings in which corresponding reference symbols indicate corresponding parts, in which:
At the outset, it should be appreciated that like drawing numbers on different drawing views identify identical, or functionally similar, structural elements of the disclosure. It is to be understood that the disclosure as claimed is not limited to the disclosed aspects.
Furthermore, it is understood that this disclosure is not limited to the particular methodology, materials and modifications described and as such may, of course, vary. It is also understood that the terminology used herein is for the purpose of describing particular aspects only, and is not intended to limit the scope of the present disclosure.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this disclosure belongs. It should be understood that any methods, devices or materials similar or equivalent to those described herein can be used in the practice or testing of the disclosure.
To clarify the spatial terminology, objects 12, 13, and 14 are used. An axial surface, such as surface 15 of object 12, is formed by a plane co-planar with axis 11. Axis 11 passes through planar surface 15; however any planar surface co-planar with axis 11 is an axial surface. A radial surface, such as surface 16 of object 13, is formed by a plane orthogonal to axis 11 and co-planar with a radius, for example, radius 17. Radius 17 passes through planar surface 16; however any planar surface co-planar with radius 17 is a radial surface. Surface 18 of object 14 forms a circumferential, or cylindrical, surface. For example, circumference 19 passes through surface 18. As a further example, axial movement is parallel to axis 11, radial movement is orthogonal to axis 11, and circumferential movement is parallel to circumference 19. Rotational movement is with respect to axis 11. The adverbs “axially,” “radially,” and “circumferentially” refer to orientations parallel to axis 11, radius 17, and circumference 19, respectively. For example, an axially disposed surface or edge extends in direction AD, a radially disposed surface or edge extends in direction R, and a circumferentially disposed surface or edge extends in direction CD.
Camshaft phaser assembly 1 for concentric camshaft assembly 2 is shown. The concentric camshaft assembly 2, which is shown in most detail in
Camshaft phaser assembly 1 adjusts the relative rotational position of inner camshaft 21 relative to outer camshaft 20 and a crankshaft (not shown) of an internal combustion engine (not shown). As shown in detail in
Camshaft phaser assembly 1 is oriented on concentric camshaft assembly 2 and torque and rotational movement are transferred between outer camshaft 20 and camshaft phaser assembly 1 by mating or meshing projections 11 on rear cover 10 with indentations 61 in outer camshaft 20. One of ordinary skill in the art will understand that projections in outer camshaft 20 can also mesh with indentations in rear cover 10. More specifically, rear cover 10 includes first protrusion 11A with first width 200 extending in a first axial direction separated from second protrusion 11B with second width 201 extending in the first axial direction. First protrusion 11A and second protrusion 11B are separated by a first circumferential distance x. Circumferential distances are defined as the distance between adjacent axially extending end walls of adjacent protrusions. Third protrusion 11C with third width 202 extending in the first axial direction is separated from the second protrusion 11B by a second circumferential distance y. In a first embodiment first width 200, second width 201 and third width 202 are different. In a second embodiment, first circumferential distance x and second circumferential distance y are different. In a third embodiment, first width 200, second width 201 and third width 202 are different and first circumferential distance x and second circumferential distance y are different. As shown in
Protrusions 11 align and mesh with indentations 61 of outer camshaft 20 in only one specific orientation. In the embodiment shown, for example, first protrusion 11A aligns and meshes with indentation 61A and second protrusion 11B aligns and meshes with indentations 61B. In this manner, rear cover 10 and camshaft phaser assembly 1 is oriented and assembled with concentric camshaft assembly 2 in a desired orientation. By using protrusions 11 and indentations 61 to orient camshaft phaser assembly 1 with concentric camshaft assembly 2, other orientation features, such as pins, may be eliminated.
Rotor 40 is then connected to the inner camshaft 21 via central bolt assembly 80 which clamps the rotor 40 to the inner camshaft 21. Central bolt assembly 80 includes a valve assembly 81 for directing pressurized hydraulic fluid to the first set of chambers 44 for rotating the rotor 40 in an advancing direction relative to the stator 50 in order to advance the timing of the inner camshaft 21, or to the second set of chambers 46 in order to rotate the rotor 40 in a direction to retard the timing of the inner camshaft 21. Hydraulic fluid can be applied to both the first and second sets of chambers 44, 46 in order to hydraulically lock the rotor 40 in a generally fixed position relative to the stator 50. An electromagnetic solenoid (not shown) is used in order to adjust the position of the valve spool 82 to direct pressurized hydraulic fluid to the passages 84, 85 as required. The valve spool 82 is biased to an initial position via a spring 86 which rests on a shoulder within the central bolt assembly 80. Pressurized hydraulic fluid is provided to the central bolt assembly 80 via pressurized hydraulic fluid being delivered through the inner camshaft 21. This travels past a check valve 87 and through a filter 88 of the central bolt assembly 80 prior to reaching the valve spool 82 which directs the pressurized hydraulic fluid to the passages 84,85 or to a drain back to the engine oil reservoir.
A helical spring 100 acts between the stator 50, via at least two of the assembly bolts 55 that engage the spring 100, and the rotor 40, via front cover 60. The spring 100 rotates the rotor 40 to a selected base position.
The camshaft phaser 1 is preassembled as a unit that can be installed in one piece on the front end of the concentric camshaft assembly 2 by aligning protrusions 11 with indentations 61, more particularly, by aligning for example first protrusion 11A with mating indentation 61A, second protrusion 11B with second indentation 61B and so on. The central bolt assembly 80 is then used to clamp the rotor 40 to the inner camshaft 21 and holds the entire phaser 1 in position axially on the front end of the concentric camshaft assembly 2.
It will be appreciated that various of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.
Number | Date | Country | |
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62118736 | Feb 2015 | US |