Endless belt power transmission systems or components – Structure facilitating lubrication of belt – pulley – or guide...
Reexamination Certificate
1997-02-18
2001-04-10
Johnson, Blair M. (Department: 3634)
Endless belt power transmission systems or components
Structure facilitating lubrication of belt, pulley, or guide...
C474S209000, C474S231000
Reexamination Certificate
active
06213904
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a low-noise chain with oil grooves having a structure for reducing noise which is made when a sprocket and a roller engage each other.
BACKGROUND OF THE INVENTION
A conventional chain for transmission or conveyance has a problem that when a tooth flank of a sprocket is engaged with a roller of a chain, noise occurs due to collision of the sprocket and the roller. For example, a technique in which a number of elastic bodies are embedded on the outer face of a bushing of a chain and an impact applied from the tooth flank of a sprocket to the roller is cushioned by the elastic bodies is proposed in Japanese Unexamined Utility Model Publication No. 59-79656.
However, the technique described in the Japanese publication No. 59-79656 has a problem such that since the elastic bodies are protruded from the outer face of the bushing, it is difficult to form an oil film by a lubricating oil and the elastic bodies are quickly worn out.
It is, consequently, considered that the impact is cushioned in the following manner. As shown in
FIG. 8
, a chain C includes outer plates O, inner plates I, a chain pin P, a bushing B, and a roller R. Oil grooves G which are narrow and long in the axial direction of the bushing B are formed at a plurality of positions in the radial direction on the outer face of the bushing B of the chain C. A portion between the bushing B and the roller R is filled with a lubricating oil L in a state where the lubricating oil L is stored in the oil grooves G. When the roller R collides with the tooth flank of a sprocket (not shown) and is impacted, the impact is cushioned by a wedge or squeeze effect of the lubricating oil L interposed between the bushing B and the roller R.
However, in the chain C with such a construction, the outer face of the bushing B is deformed to a barrel shape, i.e., bulging outward in the middle (hereinlater, simply called a barrel shape), in an assembling step of press-fitting both ends of the bushing B to bushing holes H of the inner plates I. Consequently, a clearance S between the inner face of the roller R and the outer face of the bushing B is widened near both ends of the roller R having the cylindrical inner face and the lubricating oil L easily escapes to the outside. The portion between the outer face of the bushing B and the inner face of the roller R enters a mixed or boundary lubrication state, so that the wedge or squeeze effect is not fully shown. Thus, there is a problem that the capability of reducing noise is lowered.
It is, therefore, an object of the present invention to provide a low-noise chain with oil grooves, which solves the problem of the conventional technique and in which a wedging or squeezing effect of a lubricating oil which is interposed between a bushing and a roller is effectively taught, thereby obtaining an excellent effect of noise reduction.
SUMMARY OF THE INVENTION
In order to achieve the object, according to the first aspect of the invention, there is provided a low-noise chain with oil grooves in which the oil grooves are formed on at least one of the outer face of the bushing and the inner face of the roller, and the inner face of the roller is formed in a curved face which is along an outline of a barrel shape of the outer face of the
According to the second embodiment of the present invention, there is provided a low-noise chain with oil grooves in which the oil grooves are formed on at least one of the outer face of the bushing and the inner face of the roller, and protruding portions, which can be fit into the oil grooves, are provided on at least one of the inner face of the roller and the outer face of the bushing. Preferably, the inner face of the roller is formed in a curved face which is along the outline of the barrel shape of the outer face of the bushing.
In the low-noise chain with oil grooves according to the first embodiment of the present invention, the inner face of the roller is formed in a curved shape so as to be along the outline of the barrel shape, which is formed upon assembling the chain, of the outer face of the bushing. Therefore, the clearance between the inner face of the roller and the outer face of the bushing is not widened near both ends of the roller, so that only a small amount of the lubricating oil between the roller and bushing escapes to the outside.
Since the fluid lubricating state is maintained for a long time between the bushing and the roller, and a cushioning effect of the lubricating oil is fully available for the collision when the tooth flank of the sprocket and the roller are engaged and thus, the noise caused by the collision is reduced.
In the low-noise chain with oil grooves according to the second embodiment of the present invention, when the roller is impacted by the collision of the tooth flank of the sprocket and the roller, the lubricating oil filling the oil grooves is pushed by the protruding portions and escapes from the narrow clearance between the oil groove and the protruding portions. Consequently, the squeeze or wedge effect of the lubricating oil occurs and the cushion effect for the collision is obtained, thereby reducing the noise caused by the collision.
According to the second embodiment of the present invention, when the inner face of the roller is formed in a curved face along the outline of the barrel shape of the bushing outer face, only a small amount of the lubricating oil interposing between the roller and bushing escapes to the outside, so that the effect of reducing the noise is excellently maintained for a long time.
BRIEF DESCRIPTION OF DRAWINGS
FIGS. 1 and 1
a
are a cross-sectional view and a further detailed cross-sectional view of the area enclosed by the oval in
FIG. 1
, respectively, of a chain showing the first embodiment of a low-noise chain with oil grooves according to the present invention.
FIG. 2
is a sectional view showing a state where an impact force acts on a roller of the low-noise chain oil grooves according to the present invention.
FIG. 3
is a sectional view of a chain showing the second embodiment of the present invention.
FIG. 4
is a sectional view of a chain showing the third embodiment of the present invention.
FIG. 5
is a on view of a chain showing the fourth embodiment of the present invention.
FIG. 6
is a cross-sectional view long line A—A of FIG.
5
.
FIG. 7
is a cross-section view taken along line A—A of
FIG. 5
, showing a state where an impact force on a roller.
FIGS.
8
(A) and
8
(B) are a sectional views showing a construction of a conventional low-noise chain with oil grooves.
FIG. 9
is a cross-sectional view of an embodiment where oil grooves and annular grooves are formed in the inner face of the roller.
FIG. 10
is a cross-sectional view of an embodiment wherein a plurality of protruding portions on the bushing are received in the annular grooves of the roller.
REFERENCES:
patent: 1352829 (1920-09-01), Nelson
patent: 1756759 (1930-04-01), Peterson et al.
patent: 1925055 (1933-08-01), Mize
patent: 1965145 (1934-04-01), Klaucke
patent: 3241893 (1966-03-01), Haller
patent: 3336089 (1967-08-01), Krickler
patent: 3620578 (1971-11-01), Fix
patent: 3947077 (1976-03-01), Berg et al.
patent: 4795408 (1989-01-01), Kotegawa et al.
patent: 4840498 (1989-06-01), Lichtfuss
patent: 2648328 (1978-04-01), None
patent: 396353 (1933-08-01), None
patent: 555235 (1943-03-01), None
patent: 59-79656 (1984-05-01), None
Ando Takahisa
Maeda Sachihiko
Otani Tomofumi
Takahashi Toshio
Tanaka Koji
Armstrong, Westerman Hattori, McLeland & Naughton
Johnson Blair M.
Strimbu Gregory J.
Tsubakimoto Chain Co.
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