Idler pulley

Details Idler pulley Idler pulley

1998-09-30

2001-04-24

Bucci, David A. (Department: 3682)

Endless belt power transmission systems or components

Friction drive pulley or guide roll

With stationary support for pulley or guide roll

C384S536000

Reexamination Certificate

active

06220982

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention relates to an idler pulley, particularly to an idler pulley adapted to have entrained therearound a timing belt for automobile engines or an auxiliary machine driving belt, such belt being destined to be heavily loaded.
Idler pulleys are installed to increase the wrapping angle of a belt, such as a timing belt for automobile engines or an auxiliary machine driving belt, so as to impart a suitable tension to the belt.
Some idler pulleys are of the type in which a pulley main body formed of a steel plate and having a pulley peripheral surface around which a belt is entrained is force-fitted on the outer ring of a rolling bearing, the pulley main body having a phosphate treatment applied thereto to prevent corrosion, etc.
As shown in
FIG. 3
, when this type of idler pulley is subjected to a load (radial load) from a belt entrained therearound, the pulley main body
1
and bearing
2
are slightly deformed. However, since the deformation patterns of the pulley main body
1
and bearing
2
differ, a slight clearance s is defined between the two (specifically, between the inner surface
1
a
1
of the pulley main body
1
and the outer surface
2
b
1
of the outer ring
2
b
of the bearing
2
). This clearance s becomes wider as the radial force L from the belt increases, thus decreasing the joining force between the pulley main body
1
and the outer ring
2
b
of the bearing
2
. For example, for an idler pulley in which the outer diameter of the outer ring
2
b
of the bearing
2
is 68 mm, the maximum value of said clearance s varies with the belt tension, as shown in FIG.
5
.
Therefore, when this type of idler pulley is used with a belt subjected to a heavy radial load, e.g., a timing belt, it receives a rotating force with a weak joining force exerted between the pulley main body
1
and the outer ring
2
of the bearing
2
, so that relative rotation (creep) occurs between the pulley main body
1
and the outer ring
2
b
of the bearing
2
, resulting in the wear of the fit surfaces of the pulley main body
1
and the outer ring
2
b
of the bearing
2
. Further, the pulley main body
1
is subjected to a lateral force as when the belt shifts sideways, incurring the possibility of slipping off the bearing outer ring
2
b.
Particularly, in the case where the pulley main body is formed of thin steel sheet, it tends to deform and a relatively large clearance develops, thus leading to a problem that phenomena, such as the creep described above, tend to occur.
SUMMARY OF THE INVENTION
An object of the invention, in such idler pulley having a pulley main body of steel sheet, is to prevent the creeping of the pulley main body and the outer ring of the bearing and the slipping-off of the pulley main body.
To achieve said object, an idler pulley according to the present invention is of the type in which the pulley main body of steel sheet having a pulley peripheral surface adapted to have a belt entrained therearound is force-fitted on the outer ring of a rolling bearing, said idler pulley having a layer of a metal interposed between the pulley main body of steel sheet and the outer ring of the rolling bearing, the Young's modulus of said metal being lower than those of the steel sheet pulley main body and the outer ring of the rolling bearing.
This metal layer is formed, for example, by plating with a metal whose Young's modulus is lower than those of the steel sheet pulley main body and the outer ring of the rolling bearing, applied to the inner surface of the pulley main body of steel sheet and/or the outer surface of the outer ring of the bearing.
As for metals which are lower in Young's modulus than the pulley main body of steel sheet and the outer ring of the rolling bearing, there are, for example, zinc, tin, gold, silver and copper.
Further, it is preferable that the thickness of the metal layer and the plated thickness be 5-20 &mgr;m and that the pulley main body of steel sheet have a larger width than that of the outer ring of the bearing.
That is, the idler pulley of the invention has a layer of a soft metal whose Young's modulus is lower than those of the pulley main body and the outer ring of the bearing, said layer being interposed between the inner surface of the pulley main body of steel sheet and the outer surface of the outer ring of the bearing. When a belt is entrained, this soft metal layer is elastically deformed to thereby act to fill the clearance defined between the pulley main body and the outer ring of the bearing; therefore, it is possible to prevent a decrease in the joining force between the pulley main body and the outer ring of the bearing and an occurrence of drawbacks, such as creep.


REFERENCES:
patent: 1627558 (1927-05-01), Grunwald
patent: 1903776 (1933-04-01), Clark et al.
patent: 2230744 (1941-02-01), Disbro
patent: 4362525 (1982-12-01), Sproul
patent: 4516962 (1985-05-01), Brandenstein et al.
patent: 5120279 (1992-06-01), Rabe
patent: 5728020 (1998-03-01), Muranaka et al.

Affiliated with

Also associated with

Rating

Idler pulley does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Idler pulley, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Idler pulley will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2491004