Information
-
Patent Grant
-
6786185
-
Patent Number
6,786,185
-
Date Filed
Thursday, March 14, 200222 years ago
-
Date Issued
Tuesday, September 7, 200420 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Denion; Thomas
- Corrigan; Jaime
Agents
-
CPC
-
US Classifications
Field of Search
US
- 123 906
- 074 569
- 074 595
- 074 55
- 074 596
- 074 597
- 074 598
-
International Classifications
-
Abstract
A variable valve actuation (VVA) mechanism includes a partial wrap output cam assembly and a partial wrap frame assembly. Each of the partial wrap cam assembly and the partial wrap frame assembly include a respective body and a respective shaft engaging means coupled to the body. The shaft-engaging means are configured for engaging an input shaft with a snap fit to thereby pivotally dispose the output cam assembly and the frame assembly upon the input shaft.
Description
TECHNICAL FIELD
The present invention relates to variable valve actuating mechanisms.
BACKGROUND OF THE INVENTION
Modern internal combustion engines may incorporate advanced throttle control systems, such as, for example, intake valve throttle control systems, to improve fuel economy and performance. Generally, intake valve throttle control systems control the flow of gas and air into and out of the engine cylinders by varying the timing, duration and/or lift (i.e., the valve lift profile) of the cylinder valves in response to engine operating parameters, such as engine load, speed, and driver input. For example, the valve lift profile is varied from a relatively high-lift profile under high-load engine operating conditions to a reduced/lower lift profile under engine operating conditions of moderate and low loads.
Intake valve throttle control systems vary the valve lift profile through the use of variously-configured mechanical and/or electromechanical devices, collectively referred to herein as variable valve actuation (VVA) mechanisms. Several examples of particular embodiments of VVA mechanisms are detailed in commonly-assigned U.S. Pat. No. 5,937,809, the disclosure of which is incorporated herein by reference.
Generally, a conventional VVA mechanism includes a rocker arm that is displaced in a generally radial direction by a corresponding input cam of an input shaft, such as the engine camshaft. The displacement of the rocker arm is transferred via a link arm to pivotal oscillation of an output cam relative to the input shaft. The pivotal oscillation of the output cam is transferred to actuation of an associated valve by a cam follower, such as, for example, a roller finger follower. A desired valve lift profile is obtained by orienting the output cam into a starting or base angular orientation relative to the cam follower and/or the central axis of the input shaft. The starting or base angular orientation of the output cam determines the portion of the lift profile thereof that engages the cam follower as the output cam is pivotally oscillated, and thereby determines the valve lift profile. The starting or base angular orientation of the output cam is set via a control shaft that pivots a frame member and, via the rocker and link, the output cam relative to the cam follower and/or the central axis of the input shaft.
In a multi-cylinder engine, the camshaft extends the entire length of the engine cylinder head and includes at least one cam lobe for each cylinder. The cam lobes are typically formed integrally with the camshaft, such as by machining, and are spaced along the length of the camshaft. At least a portion of the cam lobes extend outside the diameter of the camshaft. Thus, the components of the WA that are slidingly received over and mounted onto the camshaft can not be slid past the point where the first cam lobe is positioned on the camshaft. Several approaches exist that enable placement of the components of a VVA along the length of a camshaft, and on either side of the cam lobes formed thereon, thereby enabling a VVA mechanism to be associated with each cylinder.
One approach segments the camshaft into multiple sections, each of which correspond to a respective cylinder of the engine. Segmentation of the camshaft permits components of the VVA mechanism to be slid into position on either side of the cam lobe. Further, segmentation of the camshaft enables VVA mechanisms to be installed for each cylinder. However, segmentation of the camshaft increases the number of machining operations required and thus increases machining costs. Further, using segmented camshafts for each cylinder requires precise alignment of the segments relative to each other. The alignment process is time-consuming, labor intensive and costly.
Another approach uses oversized WA components. The components of the VVA mechanism are made larger so that they can be slid over the cam lobes and into association with each cylinder. However, oversized components are more costly to produce, consume more space within the engine cylinder head, and undesirably increase the weight of an engine and/or vehicle.
Yet another approach is to split the components of the VVA that are pivotally coupled to the input or camshaft into two pieces. For example, an output cam is split into upper and lower pieces. The pieces are then placed in the desired position on the camshaft and coupled together with fasteners, such as bolts, thereby pivotally coupling the split output cam to the camshaft. However, the fasteners increase the part count and make assembly of the VVA mechanism more time consuming and more complex. Further, fasteners may become loose over time or even disengage, causing the VVA mechanism to malfunction and potentially causing damage to the engine.
Therefore, what is needed in the art is a variable valve mechanism having a one-piece, unitary camshaft, thereby eliminating the need to align camshaft segments with each other.
Furthermore, what is needed in the art is a WA mechanism having fewer component parts.
Still further, what is needed in the art is a WA mechanism that does not require the use of over-sized component parts in order to be positioned on either side of a cam lobe and/or at any position along the camshaft.
Moreover, what is needed in the art is a VVA mechanism that does not require the use of split components in order to be positioned on either side of a cam lobe and/or at any position along the camshaft.
SUMMARY OF THE INVENTION
The present invention provides a variable valve actuation mechanism having an output cam and frame assembly that engage and are retained upon the camshaft of an engine with a snap fit.
The invention comprises, in one form thereof, a partial wrap output cam assembly and a partial wrap frame assembly. Each of the partial wrap cam assembly and the partial wrap frame assembly include a respective body and a respective shaft engaging means coupled to the body. The shaft-engaging means are configured for engaging an input shaft with a snap fit to thereby pivotally dispose the output cam assembly and the frame assembly upon the input shaft.
An advantage of the present invention is that the partial wrap frame and output cam assemblies eliminate the need to segment the camshaft, and the alignment process associated with a segmented camshaft.
A further advantage of the present invention is that the components can be placed on either side of an input cam lobe, or virtually anywhere along the length of a camshaft or input shaft.
An even further advantage of the present invention is that the VVA mechanism of the present invention can be at least partially assembled and retained upon a camshaft, thereby facilitating final installation in an engine.
BRIEF DESCRIPTION OF THE DRAWINGS
The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become apparent and be better understood by reference to the following description of one embodiment of the invention in conjunction with the accompanying drawings, wherein:
FIG. 1
is a perspective elevated front view of one embodiment of a variable valve actuation (VVA) mechanism of the present invention operably installed within an internal combustion engine;
FIG. 2
is a perspective side/rear view of the VVA mechanism of
FIG. 1
;
FIG. 3
is a perspective end view of the VVA mechanism of
FIG. 1
;
FIG. 4
is a perspective view of the frame assembly of
FIG. 1
;
FIG. 5
is a perspective view of the output cam assembly of
FIG. 1
;
FIG. 6
is an end view of the output cam assembly and input shaft of
FIG. 1
; and
FIG. 7
is a side view of a second embodiment of the frame assembly of the present invention.
Corresponding reference characters indicate corresponding parts throughout the several views. The exemplification set out herein illustrates one preferred embodiment of the invention, in one form, and such exemplification is not to be construed as limiting the scope of the invention in any manner.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings, and particularly to
FIGS. 1-3
, there is shown one embodiment of a VVA mechanism of the present invention. VVA mechanism
10
, as will be more particularly described hereinafter, is operably associated with rotary input shaft or camshaft
12
(hereinafter referred to as camshaft
12
) of engine
14
. Camshaft
12
has a central axis A and includes input cam lobe
12
a
, which rotates as substantially one body with rotary camshaft
12
. Valves
16
a
and
16
b
are associated with a cylinder (not shown) of engine
14
and with respective cam followers
18
a
and
18
b
(only one of which is visible).
VVA mechanism
10
includes partial-wrap frame assemblies
20
a
and
20
b
, link arms
22
a
and
22
b
, rocker arm assembly
24
, partial-wrap output cam assemblies
26
a
and
26
b
, and return springs
28
a
and
28
b
. Generally, VVA mechanism
10
transfers rotation of input cam lobe
12
a
to pivotal oscillation of output cam assemblies
26
a
and
26
b
to thereby actuate valves
16
a
and
16
b
according to a desired valve lift profile.
Partial wrap frame assemblies
20
a
and
20
b
are pivotally disposed on camshaft
12
on respective sides of input cam lobe
12
a
. More particularly, frame assembly
20
a
is pivotally disposed on camshaft
12
on a first side of input cam lobe
12
a
and frame assembly
20
b
is pivotally disposed on camshaft
12
on a second side of input cam lobe
12
a
. Frame assemblies
20
a
and
20
b
are engaged at a first end (not referenced) thereof by return springs
28
a
and
28
b
, respectively, and to rocker arm assembly
24
. Frame assemblies
20
a
and
20
b
at a second end (not referenced) thereof are pivotally coupled by respective coupling means
34
a
and
34
b
, such as, for example, shaft clamps, to control shaft
32
.
Frame assemblies
20
a
and
20
b
are substantially identical, and therefore a detailed description of one shall serve to describe the structure and functionality of both. As best shown in
FIG. 4
, frame assembly
20
a
includes a generally hook-shaped body
42
and bearing insert
44
.
Body
42
defines a bore
46
through a first end (not referenced) thereof and an elongate slot
48
in a second end (not referenced) thereof. Body
42
defines hook-shaped portion
50
including a substantially semi-cylindrical surface
52
, and end portions
54
a
,
54
b
thereof that include respective edges or lips
56
a
,
56
b
. Surface
52
has a substantially constant radius (not referenced) relative to centerline C thereof. End portions
54
a
,
54
b
are tapered away from centerline C, i.e., the distance between end portions
54
a
,
54
b
and centerline C increases in a direction radially away from semi-cylindrical surface
52
. End portions
54
a
and
54
b
are terminated by edges
56
a
and
56
b
, respectively. Bore
46
receives a fastener (not shown), such as, for example, a spring pin, to thereby couple together return spring
28
a
and frame assembly
20
a.
Bearing insert
44
includes body
62
having ends
64
a
,
64
b
, and is constructed of a resiliently-deformable material, such as, for example, steel or aluminum. Generally, bearing insert
44
is received into engagement and retained by a snap fit with semi-cylindrical surface
52
, and is thereby coupled to body
42
. More particularly, the bottom or outer surface (not referenced) of bearing insert
44
is disposed in engagement with semi-cylindrical surface
52
. Bearing insert
44
has an outside radius (not referenced) that is substantially equal to the radius (not referenced) of semi-cylindrical surface
52
. Bearing insert
44
has an inside radius R that is substantially equal to the radius (not referenced) of camshaft
12
. Angle Ø is defined between ends
64
a
and
64
b
of bearing insert
44
and centerline C of semi-cylindrical surface
52
. Angle Ø is greater than one hundred eighty degrees, and preferably from approximately one hundred eighty-one degrees (181°) to approximately two hundred twenty-five degrees (225°).
The linear distance between the radially outside surfaces (not referenced) of ends
64
a
and
64
b
is a predetermined amount greater than the distance separating the radially inner or top surfaces (not referenced) of edges
56
a
,
56
b
, i.e., the portion of edges
56
a
,
56
b
that are disposed most proximate to center C. Thus, at least a portion of ends
64
a
and
64
b
of bearing insert
44
are disposed radially outside of edges
56
a
,
56
b
, respectively, relative to centerline C. Ends
64
a
and
64
b
are disposed in close proximity and/or in abutting engagement with edges
56
a
and
56
b
, respectively, of semi-cylindrical surface
52
. Thus, edges
56
a
,
56
b
limit displacement of bearing insert
44
in a direction generally tangential to semi-cylindrical surface
52
.
Bearing insert
44
is coupled to body
42
of frame assembly
20
a
by pushing bearing insert
44
in a generally downward direction (i.e., in a direction generally from bore
46
towards slot
48
) such that the outer surface thereof engages semi-cylindrical surface
52
. As bearing insert
44
is displaced in the generally downward direction, ends
64
a
and
64
b
are deflected inward by edges
56
a
,
56
b
. Once clear of edges
56
a
,
56
b
, the resilient nature of bearing insert
44
causes ends
64
a
and
64
b
to deflect in a generally radial direction and outward relative to centerline C thereby disposing at least a portion of ends
64
a
and
64
b
radially outside of edges
56
a
,
56
b
relative to centerline C.
In general, frame assembly
20
a
is pivotally disposed and retained upon camshaft
12
by a snap fit between the outer surface (not referenced) of camshaft
12
and bearing insert
44
. More particularly, frame assembly
20
a
is pushed onto camshaft
12
such that the open portion (not referenced) of bearing insert
44
receives at least a portion of camshaft
12
, and in a direction that attempts to align centerline C of semi-cylindrical surface
52
and central axis A of camshaft
12
. As described above, bearing insert
44
is constructed of a resiliently-deformable material and has an inside radius R that is substantially equal to the radius of camshaft
12
. Since angle Ø is from approximately one hundred eighty-one degrees (181°) to approximately two hundred twenty-five degrees (225°), bearing insert
44
is deformed as frame assembly
20
a
is “pushed” onto camshaft
12
.
More particularly, ends
64
a
,
64
b
of bearing insert
44
are displaced in a generally radial direction and forced into the tapered or non-constant radius ends
54
a
,
54
b
of hook-shaped portion
50
. Once past the diameter of camshaft
12
, ends
54
a
and
54
b
of bearing insert
44
snap back into the position depicted in FIG.
4
. Thus, frame assembly
20
a
is disposed and retained upon camshaft
12
by a snap or interference fit between bearing camshaft
12
and insert
44
, which, in turn, is coupled to frame assembly
20
a
by a similar snap or interference fit.
As stated above, frame assembly
20
b
is substantially identical to frame assembly
20
a
. Thus, frame assembly
20
b
includes a bearing insert (not shown or referenced) that is substantially identical to bearing insert
44
. Frame assembly
20
b
is pivotally coupled to camshaft
12
in a substantially similar manner as that described above in regard to frame assembly
20
a
. Further, frame assembly
20
b
is also pivotally coupled to control shaft
32
.
Thus pivotally disposed upon camshaft
12
and pivotally coupled to control shaft
32
, frame assemblies
20
a
and
20
b
are not rotated by the rotation of camshaft
12
. Rather, camshaft
12
is free to rotate about central axis A and relative to frame assemblies
20
a
and
20
b
, and frame assemblies
20
a
and
20
b
are pivotable relative to camshaft
12
and central axis A thereof.
Link arms
22
a
and
22
b
are elongate arm members that are pivotally coupled at a first end thereof to opposite sides of rocker arm assembly
24
and at a second end thereof to a respective output cam
26
a
and
26
b.
Rocker arm assembly
24
is pivotally coupled, such as, for example, by pins (not referenced), at a first end thereof to frame assemblies
20
a
,
20
b
and at a second end thereof to link arms
22
a
and
22
b
. Rocker arm assembly, as is known in the art, carries one or more rollers or slider pads (not shown) that engage each of output cams
26
a
,
26
b.
Partial wrap output cams
26
a
and
26
b
are pivotally disposed upon camshaft
12
. More particularly, output cam
26
a
is pivotally disposed upon camshaft
12
on a first side of input cam lobe
12
a
, and output cam
26
b
is disposed on a second side of input cam lobe
12
a
. At respective first ends thereof, output cam
26
a
is pivotally coupled to link arm
22
a
and output cam
26
b
is pivotally coupled to link arm
22
b
, and at respective second ends thereof output cam
26
a
is coupled to spring
28
a
and output cam
26
b
is coupled to spring
28
b.
Output cams
26
a
and
26
b
are substantially identical, and therefore a detailed description of one shall serve to describe the structure and functionality of both. As best shown in
FIGS. 5 and 6
, output cam
26
a
includes a generally hook-shaped body
72
and bearing insert
74
.
Body
72
defines bores
76
a
and bore
76
b
at opposite ends (not referenced) thereof. Body
72
includes substantially semi-circular portion
82
and end portions
84
a
and
84
b
that are terminated by respective lips
86
a
and
86
b
. Semi-circular portion
82
has a substantially constant radius centered upon centerline C′. End portions
84
a
,
84
b
are tapered away from centerline C′, i.e., the distance between end portions
84
a
,
84
b
and centerline C′ increases in a direction radially away from semi-cylindrical surface
82
. Bores
76
a
receive a coupler (not referenced), such as, for example, a spring pin, to pivotally couple output cam
26
a
to return spring
28
a
. Bore
76
b
receives a fastener (not referenced), such as, for example, a spring pin, to thereby couple output cam
26
a
to link arm
22
a.
Bearing insert
74
includes body
92
having ends
94
a
,
94
b
, and is constructed of a resiliently-deformable material, such as, for example, steel or aluminum. Generally, bearing insert
74
is received into engagement and retained by a snap fit with semi-cylindrical portion
82
. Bearing insert
74
is coupled to body
72
in a substantially similar manner as described above in regard to bearing insert
44
being coupled to hook-shaped portion
50
, and is therefore not described in detail. However, it should be particularly noted that bearing insert
74
includes tab
96
that is displaced outwardly from bearing insert
74
in a generally radial direction relative to centerline C′. Tab
96
is disposed between and/or engages an inside surface of the walls (not referenced) of body
72
of output cam
26
a
, and thereby provides axial alignment of and/or positively locates bearing insert
74
relative to output cam
26
a.
Bearing insert
74
has an inside radius R that is substantially equal to the radius (not referenced) of camshaft
12
. Angle Ø′ is defined between end portions
94
a
and
94
b
of bearing insert
74
and centerline C′ of semi-cylindrical portion
82
, or alternatively between ends
84
a
,
84
b
and centerline C′. Angle Ø′ is from approximately one hundred eighty-one degrees (181°) to approximately two hundred twenty-five degrees (225°). Bearing insert
74
is coupled to body
72
by pushing bearing insert
74
in a generally downward direction (i.e., in a direction generally from bores
76
a
,
76
b
and toward semi-cylindrical portion
82
), such that the outer surface thereof engages semi-cylindrical surface
82
. As bearing insert
74
is displaced in the generally downward direction, ends
94
a
and
94
b
are deflected inward in a direction toward centerline C′ by lips
86
a
,
86
b
. Once clear of lips
86
a
,
86
b
, the resilient nature of bearing insert
74
causes ends
94
a
and
94
b
to deflect outward relative to centerline C′ to thereby dispose at least a portion of ends
94
a
and
94
b
radially outside of lips
86
a
,
86
b
relative to centerline C′.
In general, and substantially similar to frame assemblies
20
a
, output cam
26
a
is pivotally disposed and retained upon camshaft
12
by a snap fit between the outer surface (not referenced) of camshaft
12
and bearing insert
74
. More particularly, output cam assembly
26
a
is pushed onto camshaft
12
such that the open portion (not referenced) of bearing insert
74
receives at least a portion of camshaft
12
, and in a direction that attempts to align centerline C′ of semi-cylindrical portion
82
and central axis A of camshaft
12
.
As described above, bearing insert
74
is constructed of a resiliently-deformable material and has an inside radius R that is substantially equal to the radius of camshaft
12
. Since angle Ø′ is from approximately one hundred eighty-one degrees (181°) to approximately two hundred twenty-five degrees (225°), bearing insert
74
is deformed as output cam assembly
26
a
is “pushed” onto camshaft
12
. Ends
94
a
,
94
b
of bearing insert
74
are displaced radially outward and forced into the space created by the non-constant radius ends
84
a
,
84
b
of body
72
. Once past the diameter of camshaft
12
, ends
94
a
and
94
b
of bearing insert
74
snap back into the position depicted in FIG.
6
. Thus, output cam assembly
26
a
is disposed and retained upon camshaft
12
by a snap or interference fit between bearing insert
74
and camshaft
12
.
As stated above, output cam assembly
26
b
is substantially identical to output cam assembly
26
a
. Thus, output cam assembly
26
b
includes a respective bearing insert, and is pivotally coupled to camshaft
12
in a substantially similar manner as that described above in regard to output cam assembly
26
a
. Further, output cam assembly
26
b
is also pivotally coupled to its corresponding link arm
22
b.
Thus pivotally disposed upon camshaft
12
and pivotally coupled to link arms
22
a
and
22
b
, output cam assemblies
26
a
and
26
b
are not rotated by the rotation of camshaft
12
. Rather, camshaft
12
is free to rotate about central axis A and relative to output cam assemblies
26
a
and
26
b
, and output cam assemblies
26
a
and
26
b
are pivotable relative to camshaft
12
and central axis A thereof.
Return springs
28
a
and
28
b
, such as, for example, torsion springs, are each coupled at a first end to a respective frame assembly
20
a
and
20
b
and at a second end to a respective output cam
26
a
,
26
b
. As is known in the art, returns springs
28
a
,
28
b
, bias output cams
26
a
and
26
b
back into a base or starting angular orientation relative to central axis A after a valve opening event, and remove lash from VVA mechanism
10
.
It should be particularly noted that, as shown in
FIGS. 4 and 6
, bearing ends
64
a
,
64
b
and
94
a
,
94
b
are chamfered and/or of an increased radius relative to bodies
62
and
92
, respectively. More particularly, ends
64
a
and
64
b
are of bearing insert
44
are chamfered at the inside surface thereof in a direction away from camshaft
12
when bearing insert
44
is pivotally disposed in relation thereto. Similarly, ends
94
a
and
94
b
of bearing insert
74
are chamfered at the inside surface thereof in a direction away from camshaft
12
when bearing insert
74
is pivotally disposed in relation thereto.
It should further be particularly noted that, as shown in
FIG. 6
, lubricating means
98
, such as, for example, a spray nozzle or jet, is associated with VVA mechanism
10
. More particularly, with output cam assembly
26
a
pivotally disposed upon camshaft
12
, lubricating means
98
is disposed proximate to end
94
b
of bearing insert
74
. Lubricating means
98
directs a spray of lubricant L toward the interface of camshaft
12
and end
94
b
of bearing insert
74
. The chamfer and/or increased radius at end
94
b
of bearing insert
74
facilitates the admission of lubricant L, such as, for example, oil, into the interface of camshaft
12
and bearing insert
74
. Lubricating means
98
is disposed such that the spray of lubricant L is drawn into the direction of rotation D of camshaft
12
further facilitates the admission of, i.e., draws, lubricant L into the interface of camshaft
12
and bearing insert
74
.
Although not shown in the figures, it should be understood that lubricating means
98
is configured, or a second lubricating means is provided, to direct a second spray of lubricant at the interface of camshaft
12
and end
64
b
of bearing insert
44
. Alternatively, the spray of lubricant L is sufficiently dispersed such that it is simultaneously directed to interface of camshaft
12
with each of end
94
b
of bearing insert
74
and end
64
b
of bearing insert
44
.
In use, the snap-fit engagement of output cam assemblies
26
a
,
26
b
and frame assemblies
20
a
,
20
b
with camshaft
12
enables at least partial assembly of VVA mechanism
10
. The snap fit retains output cam assemblies
26
a
,
26
b
and frame assemblies
20
a
,
20
b
in disposition upon camshaft
12
. Further, the snap fit enables output cam assemblies
26
a
,
26
b
and frame assemblies
20
a
,
20
b
to be placed upon camshaft
12
and on either side of input cam lobe
12
a
, without requiring segmentation of camshaft
12
. Thus, VVA mechanism
10
eliminates the time consuming process of precisely align segments of a segmented camshaft relative to each other. Further, VVA mechanism
10
does not require the use of over-sized component parts in order to position those components on either side of cam lobe
12
a
and/or at any position along camshaft
12
. Still further, VVA mechanism
10
eliminates the need for the use of split components in order to be positioned on either side of cam lobe
12
a
and/or at any position along camshaft
12
.
VVA mechanism
10
operates, i.e., varies the valve lift of valves
16
a
,
16
b
, in a substantially similar manner as a conventional VVA mechanism. Generally, a desired valve lift profile for associated valves
16
a
,
16
b
is obtained by placing control shaft
32
in a predetermined angular orientation relative to central axis S (
FIGS. 1 and 3
) thereof, which, in turn, pivots output cam assemblies
26
a
,
26
b
relative to central axis A. Thus, the desired portion of the lift profiles of output cam assemblies
26
a
26
b
are disposed within the pivotal oscillatory range thereof relative to cam followers
18
a
,
18
b
. As output cam assemblies
26
a
,
26
b
are pivotally oscillated, the desired portions of the lift profiles thereof engage cam followers
18
a
,
18
b
to thereby actuate valves
16
a
and
16
b
according to the desired lift profile.
Referring now to
FIG. 7
, a second embodiment of a frame assembly of the present invention is shown. Frame assembly
100
includes features that are generally similar and which correspond to frame assemblies
20
a
and
20
b
, and corresponding reference characters are used to indicate such corresponding features.
Frame assembly
100
is generally similar to frame assemblies
20
a
and
20
b
, and therefore only the distinctions therebetween are discussed hereinafter. Body
42
of frame assembly
100
defines hook-shaped portion
50
including a substantially semi-cylindrical surface
52
, and end portions
54
a
,
54
b
thereof that include respective edges or lips
106
a
,
106
b
. In contrast to edges or lips
56
a
,
56
b
of frame assemblies
20
a
,
20
b
, edges
106
a
and
106
b
are angled or tapered at an acute angle (not referenced) relative to semicircular surface
52
. The acute angle facilitates installation and coupling of bearing insert
44
to body
42
of frame assembly
100
.
More particularly, the acute angle of lips or edges
106
a
and
106
b
enables one of the ends
64
a
,
64
b
of bearing insert
44
to be installed in engagement with a corresponding one of edges
106
a
,
106
b
, and thereafter permitted to resiliently deform back into a substantially semi-circular shape and pivoted in one of a clockwise or counterclockwise direction to thereby install the other of ends
64
a
,
64
b
with its corresponding edge
106
a
,
106
b.
It should be understood that, although not shown in the drawings, edges
86
a
and
86
b
of output cam assemblies
26
a
and
26
b
can be alternately configured in a manner substantially similar to edges
106
a
and
106
b
of frame assembly
100
as described above.
In the embodiment shown, bearing inserts
44
and
74
are configured for a snap fit with camshaft
12
of engine
14
. Accordingly, ends
64
a
,
64
b
and
94
a
,
94
b
, respectively, thereof form angle Ø and angle Ø′, respectively, of greater than one hundred eighty degrees 180°, and preferably from approximately one hundred eighty-one degrees (181°) to approximately two hundred twenty-five degrees (225°). However, it is to be understood that the present invention can be alternately configured with bearing inserts that engage the camshaft but are not retained thereon or pivotally coupled thereto by a snap fit. In such a configuration the bearing inserts may form an angle Ø or angle Ø′ of less than one hundred eighty degrees 180°.
While this invention has been described as having a preferred design, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the present invention using the general principles disclosed herein. Further, this application is intended to cover such departures from the present disclosure as come within the known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.
Claims
- 1. An internal combustion engine, said engine having a camshaft, said engine comprising:a variable valve actuating (WA) mechanism associated with said camshaft, said WA mechanism including at least one of a partial wrap output cam assembly and a partial wrap frame assembly pivotally disposed on said camshaft, wherein said partial wrap output cam assembly includes an output cam body, a first shaft engaging mechanism carried by said output cam body and engaging said camshaft, and wherein said first shaft-engaging mechanism comprises a resiliently-deformable first bearing insert, said first bearing insert engaging said camshaft to thereby pivotally dispose said output cam assembly upon said camshaft.
- 2. To the engine of claim 1, wherein said first bearing insert is coupled to said output cam body by a snap fit.
- 3. The engine of claim 1, wherein said output cam body defines a substantially semi-cylindrical surface and opposite end portions adjoining said semi-cylindrical surface, said first bearing insert being received and disposed within said semi-cylindrical surface.
- 4. The engine of claim 3, wherein said opposite end portions of said semi-cylindrical surface taper in a direction away from a centerline of said semi-cylindrical surface.
- 5. The engine of claim 1, wherein said first bearing insert is substantially semi-cylindrical, said first bearing insert having opposite insert body ends.
- 6. The engine of claim 5, wherein said insert body ends form an angle with a centerline of said semi-cylindrical first bearing insert of from approximately one hundred eighty one degrees (181°) to approximately two hundred twenty-five degrees (225°).
- 7. The engine of claim 5, wherein at least one of said insert body ends includes a chamfer at an inside surface thereof.
- 8. The engine of claim 5, wherein said first bearing insert further comprises at least one tab, said tab extending in a radially outward direction from said first bearing insert.
- 9. The engine of claim 1, wherein said partial wrap frame assembly includes a frame body, a second shaft engaging mechanism carried by said frame body and engaging said camshaft.
- 10. The engine of claim 9, wherein said second shaft-engaging mechanism comprises a resiliently-deformable second bearing insert, said second bearing insert engaging said camshaft with a snap fit to thereby pivotally dispose said frame assembly upon said camshaft.
- 11. The engine of claim 9, wherein said second bearing insert is coupled to said frame body by a snap fit.
- 12. The engine of claim 9, wherein said frame body defines a substantially semi-cylindrical surface and opposite end portions adjoining said semi-cylindrical surface, said second bearing insert being received and disposed within said semi-cylindrical surface.
- 13. The engine of claim 12, wherein said opposite end portions of said semi-cylindrical surface taper in a direction away from a centerline of said semi-cylindrical surface.
- 14. The engine of claim 9,wherein said second shaft engaging mechanism comprises a substantially semi-cylindrical insert body, said insert body having opposite insert body ends.
- 15. The engine of claim 14, wherein said insert body ends form an angle with a centerline of said semi-cylindrical insert body of from approximately one hundred eighty one degrees (181°) to approximately two hundred twenty-five degrees (225°).
- 16. The engine of claim 14, wherein at least one of said insert body ends includes a chamfer at an inside surface thereof.
- 17. The engine of claim 14, wherein said insert body further comprises at least one tab, said tab extending in a radially outward direction from said insert body.
- 18. The engine of claim 1, further comprising lubricating means associated with at least one of said partial wrap frame assembly and said partial wrap output cam assembly.
US Referenced Citations (13)