192 clutches and power-stop control – Clutches – Automatic
Utility Patent
2000-02-28
2001-01-02
Lorence, Richard M. (Department: 3681)
192 clutches and power-stop control
Clutches
Automatic
C192S04100R
Utility Patent
active
06167998
ABSTRACT:
BACKGROUND OF THE INVENTION
a) Field of the Invention
This invention relates to a sprag-type one-way clutch, which is adapted to be mounted between a driving shaft and a driven shaft in an automotive vehicle, general industrial equipment or the like so that motive power of rotation of the driving shaft, said rotation being only in one direction, can be transmitted to the driven shaft.
b) Description of the Related Art
A sprag-type one-way clutch is mounted between a driving shaft and a driven shaft and by way of sprags arranged between an outer ring and an inner ring, transmits rotational force of one direction from the driving shaft to the driven shaft.
When the rotational force of the one direction is applied from the driving shaft to the sprags, the sprags are wedged between the outer ring and the inner ring so that torque is transmitted to the driven shaft. Upon application of rotational force of an opposite direction, however, the sprags remain unwedged between the outer ring and the inner ring so that no transmission of torque takes place between the driving shaft and the driven shaft.
Depending primarily upon the manner of holding of sprags, these sprag-type one-way clutches can be classified into three types, that is, the single cage type, the wire cage type and the double cage type.
A description will hereinafter be made of the constructions of one-way clutches of the respective types.
A conventional one-way clutch
60
of the single cage type will be described while making reference to
FIGS. 1A through 1C
for the sake of convenience.
The one-way clutch
60
comprises plural sprags
13
, which are to be wedged between an outer ring
21
and an inner ring
22
, and a retainer
15
arranged between the outer ring
21
and the inner ring
22
and holding the sprags
13
in place.
The retainer
15
is composed of a cylindrical part
18
and a flange
17
. Sprag windows
19
for the sprags
13
are formed in the cylindrical part
18
. The flange
17
is formed in an elliptical or oval shape having a short-diameter portion and a long-diameter portion.
A ring-shaped spring
16
is fitted beforehand on the cylindrical part
19
of the retainer
15
. When the sprags
13
are inserted in the sprag windows
19
of the cylindrical part
18
and the spring
16
is fitted in spring-receiving slots formed in the sprags
13
, the sprags
13
are held in the sprag windows
19
under pressing force of the spring
16
.
As has been described above, the conventional one-way clutch
60
has substantially the same construction as a one-way clutch
10
according to a first embodiment of the present invention except that the conventional one-way clutch
60
is different in the shape of the sprag windows formed in the retainer from the one-way clutch
10
.
To show this difference more clearly, a side view of the conventional one-way clutch
60
of the single cage type is illustrated in FIG.
6
.
If any one of the sprags
13
begins to move in an axial direction of a cylindrical part
68
, one of side faces of the sprag
13
, said one side face being on a side of the moving direction of the sprag
13
, comes into contact with the corresponding one of two edges
692
,
692
out of four edges of the associated sprag window
69
formed in the retainer
65
, said two edges
692
,
692
extending in a peripheral direction of the cylindrical part
68
, so that the sprag
13
is prevented from moving in the axial direction of the cylindrical part
68
.
A description will next be made of a conventional one-way clutch
70
of the wire cage type.
FIGS. 7A and 7B
illustrate at numeral
70
the conventional one-way clutch of the wire cage type as assembled between an outer ring
21
and an inner ring
22
.
FIG. 7A
is a front view of the conventional one-way clutch
70
of the wire cage type, while
FIG. 7B
is a vertical cross-sectional view of the same conventional one-way clutch
70
taken in the direction of arrows VIIB—VIIB of FIG.
7
A.
A retainer
75
employed in this one-way clutch
70
has been formed by bending a wire in a square-U zig-zag endless form so that said wire alternately extends in an axial and peripheral directions of the retainer
75
. Each sprag
13
is arranged and held in place in a sprag window which is formed of two axially-extending adjacent portions of the wire and one peripherally-extending portion of the wire, said peripherally-extending portion connecting the axially-extending portions with each other at their proximal ends.
The one-way clutch
70
is constructed by arranging the sprags
13
in the retainer
75
, fitting a spring
16
in spring-receiving slots formed in the sprags
13
, and the arranging two side plates
72
,
74
on opposite sides of the sprags
13
.
Depending on which side each sprag
13
moves toward in the axial direction, one of the side faces of the sprag
13
, said one side face being on a side of the moving direction of the sprag
13
, comes into contact at substantially the entire area thereof with the opposing one of the side plates
72
,
74
(see FIG.
7
B).
Finally, a conventional one-way clutch
80
of the double cage type will be described while making reference to
FIGS. 4A
,
4
B,
5
A and
5
B for the sake of convenience.
The one-way clutch
80
is different in the shape of sprags and the sprag-holding structure from the above-described one-way clutch of the single cage type.
The one-way clutch
80
is constructed by holding sprags
43
in place by an outer retainer
87
shown in
FIG. 8A
, an inner retainer
88
depicted in
FIG. 8B and a
ribbon spring
50
illustrated in
FIGS. 5A and 5B
.
As is shown in the perspective view of
FIG. 5A
, the ribbon spring
50
is provided with windows formed as spaces by side bars
54
, which extend in a lengthwise direction and include plural wrinkles
540
formed at equal intervals, and also by cross bars
52
extending in a widthwise direction. A wrinkle
520
extends from a central portion of each cross bar
52
and terminates in a tab
522
.
FIG. 5B
is a perspective view, which illustrates the sprags
43
assembled in the ribbon spring
50
shown in FIG.
5
A.
When each sprag
43
with a constricted portion formed in a central part thereof is assembled in one of the windows of the ribbon spring
50
, the constricted portion of the sprag
43
is brought into contact with the tab
522
of the wrinkle
520
so that the sprag
43
is urged by the wrinkle
520
via the tab
522
.
The sprags
43
, which are in a state assembled in the ribbon spring
50
, is held by the retainers
87
,
88
which will be described below.
Incidentally, the outer retainer
87
is provided with resilient pieces (note shown) at several locations on an outer peripheral portion of the outer retainer
87
. Resilient engagement of the resilient pieces with an inner peripheral portion of the outer ring produces drag torque.
In
FIG. 4B
, numerals
94
,
96
indicate a pair of end bearings.
FIGS. 8A and 8B
are side views of the outer retainer
87
and inner retainer
88
for use in the conventional one-way clutch
80
of the double cage type.
The sprags
43
are held in sprag windows
870
,
880
, which are formed in the outer retainer
87
and inner retainer
88
, respectively.
Each of the above-described one-way clutches
60
,
70
,
80
is used by assembling it between the outer ring
21
and the inner ring
22
in such a way that the inner ring
22
is located inside the retainer or retainers and the outer ring
21
is located outside the retainer or retainers.
Each of the above-described one-way clutches of the single cage type, wire cage type and double cage type is designed so that an oil film of lubricating oil is formed at an area of contact between each edge of each sprag window of each retainer and its associated sprag or between each side plate and each sprag to produce frictional force by way of the oil film. This frictional force acts as resistance when a relative motion takes place between the retainer or retainers and the sprags or between the side plates and the sprags. It is therefore necessary to set the biasing f
Evenson, McKeown, Edwards & Lenahan P.L.L.C.
Lorence Richard M.
NSK-Warner K.K.
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