Wet type multiplate clutch

Details Wet type multiplate clutch Wet type multiplate clutch

1999-11-24

2001-09-04

Bonck, Rodney H. (Department: 3681)

192 clutches and power-stop control

Clutches

Axially engaging

C192S070200, C192S113360

Reexamination Certificate

active

06283265

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a wet type multiplate clutch for use in the automatic transmission of an automobile or the like, and more particularly to improvements in the positional relation between an oil groove for lubrication provided in a frictional material and the lubricant supply hole of a hub.
2. Related Background Art
FIG. 18
of the accompanying drawings is an axial cross-sectional view of a wet type multiplate clutch according to the prior art, and shows only the upper half thereof. A cylindrical retainer
104
is disposed on the inner periphery of a drum
105
, and splines
104
a
are formed in the inner periphery of the retainer
104
. Annular separator plates
103
are in meshing engagement with the splines
104
a.
Respective friction plates
107
are disposed between adjacent ones of the separator plates
103
, and teeth of the inner peripheral edges thereof are in meshing engagement with splines provided on the outer periphery of a hub
108
. A flange
102
for receiving the friction plate
107
is disposed on the drum opening side end portion of the retainer
104
, and is axially fixed by a snap ring
101
. On the other hand, a piston
109
is provided on the closed side of the drum, and oil is introduced into an oil chamber
113
and pressure is created, whereby the piston is axially moved and brings each friction plate
107
and adjacent separator plate
103
into frictional engagement with each other.
An O-ring
106
which is a seal member is provided on the sliding surface of the piston
109
. Lubricant supply holes
112
are formed in the hub
108
rotatable in the direction of the arrow so as to cool frictional materials
110
secured to the friction plates
107
.
FIG. 19
of the accompanying drawings is a front view of a friction plate
107
meshing with the spline of the hub
108
.
FIG. 19
shows a quarter of the whole.
The hub
108
is formed with lubricant supply holes
112
, and the frictional materials
110
are formed with through-oil grooves
111
extending through the inner and outer edges thereof and enhancing the cooling effect, and non-through-oil grooves
114
opening only to the inner peripheral edge and reducing the initial coefficient of dynamic friction during the frictional engagement thereof.
In the conventional example shown in
FIG. 18
, with regard to the second one from the piston side, the opening portion of the through-oil groove
111
is located at the front of the lubricant supply hole, but the opening portions of the through-oil grooves
111
of the other friction plates
107
are not opposed to the lubricant supply holes
112
.
In recent years, the fact that drag torque is created by the viscosity of the lubricant used in the wet type multiplate clutch and results in a reduction in efficiency has posed problems. These problems cannot be solved by the conventional construction.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a wet type multiplate clutch in which the construction of oil grooves in frictional materials is improved to thereby reduce drag torque and improve the dischargeability of a lubricant.
To achieve the above object, the wet type multiplate clutch of the present invention is a wet type multiplate clutch in which outer tooth plates and inner tooth plates rotatable relative to each other are coaxially alternately disposed and are frictionally engaged with each other, wherein among a plurality of oil grooves having opening portions opening to the inner peripheral edges of frictional materials secured to said inner tooth plates, at least one of said opening portions is opposed to a lubricant supply hole formed in a hub.
Of the plurality of oil grooves having opening portions opening to the inner peripheral edges of the frictional materials secured to the inner tooth plates, at least one of the opening portions is opposed to the lubricant supply hole formed in the hub and therefore, the efficiency of the supply of the lubricant to the oil grooves formed in the frictional materials increases. Also, non-through-oil grooves have the function of pressure created therein urging the plates away from one another.
Further, by adopting a shape in which only the particular portions of splines differ from one another, the error of assembling can be prevented. Also, of the lubricant supplied through the lubricant supply holes, the rate at which it is supplied to the oil groove in which the opening portion opposed to the lubricant supply hole is located is 50% or more. Specifically, lubricant supply holes of the same shape are disposed at equal intervals in the hub, and the rate at which said opening portions of said oil grooves are located at the front of said lubricant supply holes may be 50% or more.
According to one aspect of the invention, there may be two kinds of oil grooves, namely oil grooves extending through the inner peripheral edge and the outer peripheral edge and oil grooves extending through only the inner peripheral edge. The two kinds of grooves may be alternately radially disposed at equal intervals. Oil grooves having an angle of inclination with respect to the center line thereof (i.e., non-radial oil grooves may also be used).
Further, particular portions of the inner tooth plates and the splines of the hub may be of different shapes, so that when they are combined together at a position whereat they can be combined together, the at least one oil groove opening portion is positioned at a position opposed to a lubricant oil supply hole. For example, convex portions or concave portions may be formed on the particular portions of the splines of the hub, and mesh with concave portions or convex portions formed on the splines of the inner tooth plates, and the pitch of the peak portions or the pitch of the valley portions of the splines formed on the hub differs at particular portions. When the oil grooves having an angle of inclination are used, the differently shaped portions of the hub and the inner tooth plates may be made asymmetrical in order to prevent the assembling in the opposite direction and thereby assure proper orientation of the inclined oil grooves relative to the direction of rotation.


REFERENCES:
patent: 4287978 (1981-09-01), Staub
patent: 4450944 (1984-05-01), Fujioka et al.
patent: 5094331 (1992-03-01), Fijimoto et al.
patent: 5101953 (1992-04-01), Payvar
patent: 5439087 (1995-08-01), Umezawa
patent: 5682971 (1997-11-01), Takakura et al.
patent: 6062367 (2000-05-01), Hirayanagi et al.
patent: 11-141570 (1999-05-01), None

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