Lubrication system for one-way clutch

Disclosed is a lubrication system for a one-way clutch which is provided with an inner ring, an outer ring, and an end bearing having an inner and outer peripheral walls and disposed between the inner ring and the outer ring. The end bearing is provided on a side wall thereof with convexities extending in an axial direction. The convexities are partly open, thereby forming flow passages through which a lube oil scattered from a side of the inner ring toward a side of the outer ring is allowed to flow into the one-way clutch.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a lubrication system for a one-way clutch. 
2. Description of the Related Art 
Among one-way clutches which can transmit rotating force in only one 
direction but idle in the opposite direction, so-called sprag or roller 
one-way clutches are widely used these days. In such a sprag or roller 
one-way clutch, clutch members such as sprags or rollers are arranged 
between an inner ring and an outer ring and are guided at both side walls 
thereof by end bearings, respectively, so that the clutch members engage 
he outer and inner rings upon transmission of rotating force but undergo 
sliding upon idling. 
The fundamental construction of a one-way clutch is illustrated in FIG. 4, 
in which there are shown an inner ring 10, an outer ring 20, clutch 
members 30, end bearings 45, an oilway 50 for introducing a lube oil into 
the clutch, and a stop ring 60. 
In a one-way clutch, clutch members repeatedly undergo engagement with an 
inner and outer rings and sliding due to idling. Substantial heat 
generation and friction therefore occur unless sufficient lubrication is 
applied. Further, it is also necessary to supply a lube oil sufficiently 
to avoid irregular rotation and/or seizure because end bearings are 
usually sliding bearings. 
For this purpose, the one-way clutch is provided at a mounting portion 
therefor with a special lube-oil passage like the oilway 50 as shown in 
FIG. 4. 
Even if a lube oil passage such as that shown in FIG. 4 is provided, supply 
of a lube oil into the one-way clutch cannot be performed surely when the 
inner ring remains stationary although the lube oil can be surely supplied 
into the one-way clutch under centrifugal lubricating action when the 
inner ring rotates. In the former case, a large majority of the lube oil 
does not flow through the oilway 50 in the inner ring 10 but is caused to 
scatter around the one-way clutch as indicated by arrows F, resulting in 
the problem that lubrication of the one-way clutch is impaired. 
To achieve sufficient lubrication, it is necessary to increase the capacity 
of an oil pump as a supply source for the lube oil. An increase in the 
supply of the lube oil, however, leads to greater agitation resistance and 
viscous resistance due to the lube oil remaining in a larger amount around 
the one-way clutch, resulting in a greater power loss. 
SUMMARY OF THE INVENTION 
An object of the present invention is to sufficiently supply a lube oil 
into a one-way clutch without relying upon an oil pump having a greater 
capacity. 
In one aspect of the present invention, there is hence provided a 
lubrication system for a one-way clutch provided with an inner ring, an 
outer ring, and an end bearing having an inner and outer peripheral walls 
and disposed between the inner ring and the outer ring. The end bearing is 
provided on a side wall thereof with convexities extending in an axial 
direction. The convexities are partly open, thereby forming flow passages 
through which a lube oil scattered from a side of the inner ring toward a 
side of the outer ring is drawn into the one-way clutch. 
As the lubrication system according to the present invention for the 
one-way clutch is constructed as described above, openings of the 
convexities catch scattered lube oil and the thus-caught lube oil is 
introduced into the one-way clutch through the openings as flow passages. 
No large capacity is therefore needed for an oil pump as a lube oil supply 
source, a power loss is reduced, and the overall weight and dimensions of 
the one-way clutch are reduced. An improvement in gas mileage can 
therefore be expected.

DETAILED DESCRIPTION OF THE INVENTION AND PREFERRED EMBODIMENTS 
Referring first to FIGS. 1A and 1B, the end bearing forming the lubrication 
system according to the first embodiment of the present invention will be 
described. The end bearing 40 is provided on a side wall thereof with 
convexities 124, which are partly open to define openings 125. These 
figures also illustrate an inner peripheral wall 121, an outer peripheral 
wall 122 and the side wall 123, all of the end bearing 40. Each opening 
125 is directed against the inner peripheral wall 121 and serves as a flow 
passage for a lube oil. 
The end bearing forming the lubrication system according to the second 
embodiment of the present invention will next be described with reference 
to FIGS. 2A and 2B. Designated at numeral 134 are convexities arranged on 
a side wall 123 of the end bearing 41. Numeral 135 indicates an opening of 
each convexity 134. 
Each convexity 124 in the first embodiment shown in FIGS. 1A and 1B is in 
the form of a zone of a sphere (i.e., a portion of a sphere, which is 
contained between two imaginary parallel planes intersecting the sphere) 
and its opening 125 is obliquely directed against the inner peripheral 
wall 121 of the end bearing 40. Each convexity 134 in the second 
embodiment depicted in FIGS. 2A and 2B is in the form of a step and its 
opening 135 is perpendicularly directed against the inner peripheral wall 
121 of the end bearing 41. These openings 125, 135 serve as flow passages 
for the lube oil. It is to be noted that the shape of each convexity is 
not limited to those illustrated in the figures. For example, each 
convexity may be in the form of a quadrantal (1/4) sphere. 
FIG. 3 illustrates the one-way clutch in which the end bearing 40, which 
are shown in FIGS. 1A and 1B and forms the lubrication system according to 
the first embodiment of the present invention, is assembled. Similarly to 
FIG. 4, there are illustrated the inner ring 10, the outer ring 20, the 
clutch members 30, the conventional convexity-free end bearing 45, the 
oilway 50, and the stop ring 60. 
The end bearing 40 is provided on the side wall thereof with the 
convexities 124, which are partly open to define the openings 125 directed 
toward the inner peripheral wall 121 (see FIGS. 1A and 1B). The lube oil 
scattered from a side of the inner ring 10 toward a side of the outer ring 
20 without flowing through the oilway 50 as indicated by arrow F is drawn 
into the one-way clutch through the openings 125, thereby making it 
possible to surely supply the lube oil. A lube oil in a one-way clutch 
with the end bearing 41 forming the lubrication system according to the 
second embodiment shown in FIGS. 2A and 2B is supplied similarly.