Field of the Disclosure
[001] The present invention relates to tensioners, and more specifically, belt tensioners
having adjusters for easily and precisely installing the tensioners in operative relation with a belt,
such as a timing or drive belt.
Description ofRelated Technology
[002] Belt tensioners have been utilized in many belt systems. It is conventional
practice in belt tensioners to apply a constant belt tensioning force which compensates for
increases in belt length due to wear and other factors. A common type of conventional belt
tensioner includes a fixed structure and a pivoted structure pivotally mounted on the fixed
structure by a pivot assembly. The pivoted structure carries a belt-engaging pulley. A coil or
torsion spring is mounted in surrounding relation to the pivot assembly and has its ends
connected between the fixed and pivoted structures so as to bias the latter toward a position of
maximum belt take-up so that the spring biasing force decreases as the pivoted structure moves
from a position of minimum take up to a position of maximum belt take-up. Despite this varying
spring force within the range of movement provided, a substantially constant belt tension is
maintained.
[003] When belt tensioners are installed on an engine they should be installed so as to
apply a predetermined static tensioning force to the belt. In addition, the pivoted structure, which
conventionally carries the pulley, is movable between two positions defined by end stops. During
the adjustment or installation of the tensioner, an adjusting member or an eccentric adjusting
member, which forms part of the fixed structure, is adjusted to move the pivoted structure into a
position between the stops, wherein the belt tensioning pulley is disposed in a predetermined
static tensioning relation to the belt.
[004] Many adjusters for tensioners are manufactured as a two-piece construction, for
example, in an injection molded, die cast or stamped process. The two-piece manufacturing
process can be costly and time-consuming due to, for example, the re-tooling efforts that are
needed when manufacturing different sized eccentric adjusters and different sized eccentric
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tensioners. What is needed is a tensioner adjuster that can be more economically and sustainably
manufactured for a variety of differently sized eccentric adjusters and tensioners.
SUMMARY
[005] In one embodiment of the present disclosure a tensioner includes a base, a sleeve
having a bore and connected to the base, an arm pivotally engaged with the base about the
sleeve, a pulley journaled to the arm, a torsion spring engaged between the arm and the base, and
an adjuster. The adjuster is rotatably mounted within the center bore of the sleeve and includes: a
plate portion having an opening for receiving a fastener, a first neck portion extending from the
plate portion, a first guide portion extending from the first neck portion with a fastener engaging
member for engaging the fastener, a second neck portion extending from the plate portion on a
side of the plate portion opposite from the side of the plate portion from which the first neck
portion extends, and a second guide portion extending from the second neck portion with a
fastener engaging member for engaging the fastener.
[006] In another embodiment of the present disclosure, a tensioner adjuster includes a
plate portion having an opening for receiving a fastener, a first curved neck portion extending
from the plate portion, a first guide portion extending from the first curved neck portion with a
fastener engaging member for engaging the fastener. The tensioner further includes a second
curved neck portion extending from the plate portion on a side of the plate portion opposite from
the side of the plate portion from which the first curved neck portion extends, and a second guide
portion extending from the second curved neck portion with a fastener engaging member for
engaging the fastener.
[007] In yet another embodiment of the present disclosure, a tensioner adjuster includes
a plate portion having an opening for receiving a fastener for installation of a tensioner, a first
curved neck portion extending from the plate portion, and a first guide portion extending from
the first curved neck portion with a fastener engaging member constructed and arranged to
engage the fastener. The tensioner further comprises a second curved neck portion extending
from the plate portion on a side of the plate portion opposite from the side of the plate portion
from which the first curved neck portion extends, and a second guide portion extending from the
second curved neck portion with a fastener engaging member constructed and arranged to
engage the fastener. The tensioner further includes a first reinforcing support that extends from
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the first curved neck portion, a second reinforcing support that extends from a side of the first
curved neck portion that is opposite the side from which the first reinforcing support extends, a
third reinforcing support that extends from a side of the second curved neck portion, and a fourth
reinforcing support that extends from a side of the second curved neck portion that is opposite
the side of the second curved neck portion from which the third reinforcing support extends.
[008] Other aspects of the invention will be explained or made obvious by the following
description of the invention and the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[009] The accompanying drawings, which are incorporated in and form a part of the
specification, illustrate preferred embodiments of the present invention, and together with a
description, serve to explain the principles of the invention.
[0010] FIG. 1 is a perspective view of an embodiment of a tensioner with an adjuster of
the present disclosure.
[0011] FIG. 2 is another perspective view of an embodiment of the tensioner with an
adjuster of the present disclosure.
[0012] FIG. 3 is a top plan view of an embodiment of the tensioner with an adjuster of
the present disclosure.
[0013] FIG. 4 is a cross-sectional view of an embodiment of the tensioner with an
adjuster of the present disclosure taken along lines A-A of FIG. 3.
[0014] FIG. 5 is an exploded view of an embodiment of the tensioner with an adjuster of
the present disclosure.
[0015] FIG. 6 is a perspective view of an embodiment of the adjuster for the tensioner of
the present disclosure.
[0016] FIG. 7 is another perspective view of an embodiment of the adjuster for the
tensioner of the present disclosure.
[0017] FIG. 8 is another perspective view of an embodiment of the adjuster of the present
disclosure after being stamped and prior to forming the adjuster into the structure of the adjuster
for use in installing the tensioner of the present disclosure.
[0018] FIG. 9 is a top view of an embodiment of the adjuster for the tensioner of the
present disclosure.
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[0019] FIG. 10 is a bottom view of an embodiment of the adjuster for the tensioner of the
present disclosure.
[0020] FIG. 11 is a left side view of an embodiment of the adjuster for the tensioner of
the present disclosure.
[0021] FIG. 12 is a right side view of an embodiment of the adjuster for the tensioner of
the present disclosure.
[0022] FIG. 13 is a front side view of an embodiment of the adjuster for the tensioner of
the present disclosure.
[0023] FIG. 14 is a back side of an embodiment of the adjuster for the tensioner of the
present disclosure.
DETAILED DESCRIPTION
[0024] The tensioner adjuster of the present disclosure comprises an eccentric adjuster.
The eccentric adjuster may be used to move a tensioner into proper engagement with a belt
during installation. The eccentric adjuster may be manufactured by stamping a single piece of
material, e.g., a sheet metal material, and forming the single piece of stamped material into an
adjuster structure that assists in the installation of a belt tensioner, for example, onto a motor
vehicle engine by moving the pivoted structure into a position between stops in which the belt
tensioning pulley is placed into predetermined static tensioning relation to the belt. The process
of stamping the adjuster material into a single piece and forming the single piece of stamped
material into the adjuster structure enables eccentric adjusters to be manufactured with different
sizes for use with different sized eccentric tensioners, without requiring tooling changes during
manufacturing. The adjusters of the present disclosure are accordingly made without expensive
and time-consuming re-tooling efforts during manufacturing, which substantially reduces per
unit adjuster manufacturing costs. The reduction in re-tooling during manufacturing not only
provides significant economic benefits, but also creates a more environmentally sustainable
manufacturing process.
[0025] FIGS. 1-14 illustrate a tensioner 100 with a one-piece adjuster 50 according to an
embodiment of the present disclosure. Tensioner 100 comprises an adjuster 50 that is eccentric
and used to move tensioner 100 into proper engagement with a belt during installation, for
example, during the installation of tensioner 100 onto a motor vehicle engine, as discussed
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herein. It should be appreciated from the foregoing that FIGS. 9-14 illustrate the same adjuster
embodiment illustrated in FIGS. 1-8.
[0026] During installation, adjuster 50 is rotated about a fastener, such as a bolt or stud or
any other suitable fastener (fastener not shown), that passes through an opening 52 defined in
adjuster 50. When the fastener extends through opening 52, the fastener is engaged with, or
guided or held in place by, engaging members 600, 700 (of respective first and second guide
portions 59a, 59b of adjuster 50 as discussed below). The fastener inserted into opening 52
extends to a distal end of tensioner 100 where the fastener secures tensioner 100 to, for example,
a motor vehicle engine. The center of the fastener that extends through opening 52 and is guided
or held by the first and second engaging members 600, 700 defines an axis of rotation B-B for
the fastener (See, FIG. 4). Axis B-B is eccentrically offset from an axis of rotation of pulley 30
C-C (See, FIG. 4), and is eccentrically offset from an axis of rotation of the pivotal arm 20 of
tensioner 100 (the axis of rotation for arm 20 is unlabeled). Eccentric adjuster 50 is used to
precisely load a belt (not show) that is engaged with pulley 30 with a predefined tension by
compensating for all component tolerances. Adjuster 50 is used during belt installation and
locked in place once the belt is installed by fully engaging the fastener with a mounting surface,
for example, with motor vehicle engine. Eccentric in the term eccentric adjuster 50 refers to the
axis of fastener rotation B-B not being coaxial with the axis of rotation C-C of a pulley 30 or
with the axis of rotation of arm 20, which is defined by another axis (unlabeled) that is
substantially parallel to axis B-B.
[0027] Pulley 30 engages a belt to provide belt tension or load. Pulley 30 is journalled to
arm 20 about a bearing or bearing assembly 32. Pulley 30 is engaged with an outer race of
bearing 32. Bearing 32 comprises a ball bearing but may comprise a needle bearing or any other
suitable bearing.
[0028] Arm 20 comprises or has a center bore or opening 23 defined therein. Arm 20 is
biased by a coil or torsion spring 40 to urge pulley 30 into the belt (not shown). Arm 20 pivots
about sleeve 70 about a bushing 60. Bushing 60 allows arm 20 to rotate smoothly about sleeve
70 and contributes to friction damping. Bushing 60 may comprise a low friction material for
facilitating the relative movement of arm 20, e.g., a material comprising brass, copper and
sintered metal. The pivotal movement of arm 20 about sleeve 70 results in a translational
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movement of pulley 30 that allows tensioner 100 to compensate for any changes in belt length as
the belt stretches over time and as the drive length changes from thermal expansion.
[0029] Arm 20 is engaged with an inner race of bearing 32. Pulley 30 is pressed into
engagement against the belt by a torsion spring 40. A first end or arm engaging end 42 of torsion
spring 40 is engaged with a slot 22 defined in arm 20. A second opposite end or base engaging
end 44 of torsion spring 40 is engaged with base 10 in a slot (not labeled) defined in a spring
engaging member 14 of base 10.
[0030] Base 10 is statically fixed during installation of tensioner 100 to a mounting
surface, such as an engine of a motor vehicle (not shown). Spring torque from torsion spring 40
and the effective arm length of arm 20 creates a belt load or tension. Tang 16 of base 10 engages
a cooperating receiving member on the mounting surface such as a hole in the mounting surface
(not shown) and is used to prevent rotation of base 10 during installation oftensioner 100. While
base 10 is used to mount tensioner 100, base 10 is also used to secure an end of the torsion spring
40, e.g., to secure base engaging end 44 of torsion spring 40 in a slot defined in spring engaging
member 14 ofbase 10.
[0031] Sleeve 70 is attached or fixed to base 10, e.g., via a mechanical interference fit,
and is generally or substantially cylindrically shaped having a bore 72 defined therein. Sleeve 70
and its bore extend from a distal end 76 of sleeve 70 to a proximal end 74 of sleeve 70. Distal
end 76 of sleeve 70 comprises a circumferential collar 78. Sleeve 70 further comprises a shoulder
72a that extends circumferentially around, and is defined by, an interior or inside wall of the bore
72 defined in sleeve 70 (See FIG. 4 showing shoulder 72a of sleeve 70).
[0032] A damper 80 is mounted to sleeve 70 and arranged in tensioner 100 between base
10 and arm 20 to act as a damping control member. Damper 80 is held axially by sleeve 70 and
is rotationally fixed by, for example, spring 40 being inserted through a slot or opening in the
damper 80 that may align rotationally with the slot defined in the spring engaging member 14 of
base 20. Damper 80 controls and reduces oscillations of arm 20 during operation and may
comprise and material suitable for reducing and controlling oscillations of arm 20.
[0033] Arm 20 comprises an arm indicator 24 that cooperates with a base indicator 12 of
base 10 to display when tensioner 100 is properly installed and loaded during installation. Pulley
30 comprises a belt engaging surface (not labeled), which may be flat as shown, or any other
suitable shape or profile for engaging a belt.