Endless belt power transmission systems or components – Plural belts or plural output loads – Plural belts having interengaged drive surfaces
Reexamination Certificate
1999-04-23
2001-03-20
Hannon, Thomas R. (Department: 3682)
Endless belt power transmission systems or components
Plural belts or plural output loads
Plural belts having interengaged drive surfaces
C474S242000, C474S206000
Reexamination Certificate
active
06203460
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a power transmission chain belt and, in particular, to a power transmission chain belt for use with a continuously variable transmission (CVT). More particularly, the present invention relates to a chain belt for a CVT with an asymmetrical guide link and a modified strut and link geometry that places the strut closer to the pitch line of the chain.
The belt of the present invention is comprised of a large number of interleaved link plates which are placed parallel to the chain width direction and carry a number of load blocks or struts for transmission of power to the variable width pulleys of the CVT. The belt is formed of a plurality of adjacent chain portions that are offset or phased by a portion of one chain pitch. Preferably, the belt is formed of at least two adjacent chain portions that are offset or phased by one-half pitch.
An example of a power transmission chain belt as used in a CVT is shown in
FIG. 1
of the drawings. As shown in that figure, the CVT includes input shaft
101
a
and output shaft
102
a
, which carry primary (drive) and secondary (driven) pulleys
103
a
,
104
a
, respectively. The chain belt
105
a
interconnects the primary and secondary pulleys of the CVT.
Primary pulley
103
a
includes fixed pulley portion
103
a
′, which is fixed to input shaft
101
a
, and moveable pulley
103
b
′, which is moveable along input shaft
101
a
. Similarly, secondary pulley
104
a
includes fixed pulley
104
a
′, which is fixed to the output shaft
102
a
and moveable pulley
104
b
′, which is moveable along the output shaft. The effective diameters of pulleys
103
a
and
104
a
are changed by movement of the moveable pulley portions
103
b
′,
104
b
′, which is caused by operation of hydraulic actuators, as is known in the art. In this manner the speed change ratio between the input and output shafts can be varied continuously.
FIG. 2
generally illustrates a sectional view of a portion of a chain of the prior art for use in a variable pulley transmission of the type schematically illustrated in U.S. Pat. No. 5,007,883, which is incorporated herein by reference. The chain
10
comprises two chain assemblies or two chain portions
12
,
14
. The two portions
12
,
14
are disposed in side-by-side relationship with the chain portions being offset from one another by one-half pitch. That is, the first chain
12
and second chain
14
are offset from each other by one-half pitch.
The two chain portions are interleaved and connected by pairs of pivot pins
16
,
18
that extend through apertures in each of the links. One pin
16
is longer than the other pin
18
and extends through a guide link on the outside of the chain, as explained in more detail below.
The first portion of the chain includes a plurality of rows or sets
20
,
22
of interleaved inner links
41
. The inner links
41
, shown more clearly in
FIG. 8
, are interlaced so that the apertures
48
,
50
of one link set are transversely aligned with the apertures of the links of the next adjacent set. In this way, the rows of links articulate with respect to one another. The inner links include a pair of depending toes
42
,
44
that extend downwardly from the link body. The toes define a passageway
45
for the retention of a strut
11
, which is explained in more detail below.
The first portion of the chain of the prior art as shown in
FIG. 2
includes retaining links
47
on alternate rows of the chain. The rows with retaining links include five links across each row. That is, three inner links with a retaining link on each outside. Retaining links are present in prior art chain assemblies to restrict excessive lateral motion of the strut. The retaining links are located on the ends of the link rows not containing guide links. The link passageway is shaped to restrict excessive lateral motion of the struts in the adjacent row. The rows without retaining links include four inner links across the width of the chain. Guide links
24
,
36
are placed outside the retention links.
The inner links and retaining links include pairs of apertures that permit pairs of pins to extend through each aperture. The guide links include pairs of apertures that permit only a single pin to extend through each aperture. The single pin is fit securely in the aperture of the guide link and does not rotate with respect to the guide link. The pairs of pins in each aperture of the inner links rotate or rock with respect to one another, which permits the articulating motion of the inner links and rows of interleaved inner links. The use of rocker joints and pins in apertures of CVT chains as well as silent chains is well-known in the art. A pin and rocker joint is shown in U.S. Pat. No. 4,507,106, which is incorporated herein by reference. Pairs of pivot members extend across the length of the first portion of the chain and terminate slightly beyond the ends of the retaining members.
The second chain, or other chain portion, of the chain belt is also comprised of a plurality of interleaved inner links. The inner links are interlaced so that the apertures of one link set are transversely aligned with the apertures of the next adjacent set. In this way, the rows of links articulate with respect to one another.
The second portion of the chain also includes retaining links on alternate rows of the chain. The rows with retaining links include five links across each row. That is, three inner links with a retaining link on each outside. The rows without retaining links include four inner links across the width of the chain. The inner links in the second portion of the chain act in a similar manner to the inner links in the other portion of the chain. The links also include pivot members and rocker joints, in the same manner as the first portion of the chain.
Referring to
FIG. 3
, a long outboard load block or strut is held in the passageways formed between the depending toes of the links to engage the flanges of the pulleys. The strut
11
is symmetrical about a vertical centerline in the end direction and in the lengthwise (or transverse) direction. The strut includes a top
80
, two rounded link contacting surfaces
82
,
84
, two grooves
86
,
88
, a first side
90
, a second side
92
, and a bottom
94
. The upper region of the strut, including the top and the rounded contacting surface, is similar in shape to the passageway and is only slightly smaller in size to allow the strut to be positioned in the passageway of the link.
In
FIG. 4
, a front view of the strut
11
shown in
FIG. 3
, the top of the strut includes an upper portion
80
a
and an extending portion
80
b
and ends
96
,
98
that contact the flanges of the pulleys.
FIG. 5
illustrates a guide link
36
of the prior art. The link
36
has a pair of apertures
148
,
150
for receiving the pins of an associated rocker joint pivot member. The apertures, and link configuration, is generally symmetrical about a vertical centerline. The link comprises a top
130
, preferably substantially horizontal, and a bottom having two spaced depending toes
142
,
144
that define a passageway
100
for the upper portion of a strut. The depending toes are shaped to hold the strut within the passageway
100
.
FIG. 6
illustrates the aperture
150
in more detail. The aperture includes upper and lower curved portions
152
,
154
. The back portion
156
is preferably slightly curved to permit the pin to seat against the back portion. The front portion
158
is also curved at a radius that matches the radius of the rocker pin. A rocker pin is fit securely into the aperture
150
.
FIG. 7
illustrates the passageway
100
a
of the link in more detail. In
FIG. 7
, the passageway has rounded inner portions
102
,
104
and a rounded upper portion
105
. The rounded inner portions form two toes
106
,
108
at the bottom of the link. The upper portion of the strut is shaped to match the upper portion
105
and inner portions
102
,
104
of the link.
FIG. 8
illustrates inner link
41
ha
Parks Laurence
Reese Mark D.
Borg-Warner Inc.
Charles Marcus
Dziegielewski Greg
Hannon Thomas R.
Sidley & Austin
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