192 clutches and power-stop control – Clutches – Fluent material
Reexamination Certificate
2000-04-21
2001-09-25
Lorence, Richard M. (Department: 3681)
192 clutches and power-stop control
Clutches
Fluent material
C192S1030FA, C192S11000B
Reexamination Certificate
active
06293381
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a hydraulic power transmission joint for use in distribution of vehicle driving powers, and more particularly to a hydraulic power transmission joint aiming to prevent a lowering of torque arising from oil leakage and thus from hydraulic pressure reduction.
2. Description of the Related Arts
Conventional hydraulic power transmission joints are known from e.g., U.S. Pat. Nos. 5,706,658 and 5,983,635.
FIG. 1
illustrates an example of a hydraulic power transmission joint being currently developed by the inventors of the present application on the basis of the above Patents, and
FIG. 2
is an enlarged view of the major part thereof. Referring to
FIGS. 1 and 2
, a propeller shaft
101
acting as an input shaft is coupled to a companion flange
102
into which is fixedly inserted a housing shank
104
having a cam face
103
formed on its inner face. A housing
105
is secured by welding to the housing shank
104
. The housing shank
104
is supported via a front bearing
106
by a differential gear case
107
. A main shaft
108
acting as an output shaft connects with a drive pinion gear
109
associated with a rear differential gear. A rotor
110
is fitted via splines to the main shaft
108
and is rotatably housed in the housing
105
. The main shaft
108
is supported via a rear bearing
111
by the differential gear case
107
. The rotor
110
is provided with a plurality of axially extending plunger chambers
112
which accommodate plungers
113
reciprocatively under a pressing force of return springs
114
, with the plungers
113
being operated by the cam face
103
upon the relative rotations between the two shafts. The plunger
113
has a one-way valve
115
for intake disposed at its head. The rotor
110
is formed with a discharge hole
116
leading to the plunger chambers
112
. The discharge hole
116
is provided with a one-way valve
117
for discharge. A valve block
118
coupled to the rotor
110
has a high-pressure chamber
119
leading to the discharge hole
116
and has an orifice
120
acting as flow resistance generating means for generating a flow resistance by the flow of oil discharged by the operation of the plungers. A bearing retainer
121
is securely press-fitted to the housing
105
and is positioned by a snap ring
122
. Needle bearings
123
and
124
are interposed between the bearing retainer
121
and the valve block
118
and between the bearing retainer
121
and the main shaft
108
, respectively. A thrust washer
125
is further provided between the bearing retainer
121
and the main shaft
108
. An accumulator piston
126
is provided for absorbing thermal expansion and contraction of oil residing within the joint.
In such a hydraulic power transmission joint, however, the bearing retainer
121
is supported via the needle bearing
124
by the main shaft
108
, whereas the bearing retainer
121
presses the main shaft
108
by way of the thrust washer
125
, with the result that rotational secondary torque and thrust-up load input from the propeller shaft
101
enters the interior of the joint and the rotational secondary torque becomes a moment separating the valve block
118
from the rotor
110
, allowing a leakage of oil through the gap therebetween, which disadvantageously results in a lowering of toque. The thrust-up load is received by the main shaft
108
while the rotational difference between the input and output is absorbed by way of the thrust waster
125
, with the result that abrasions and noises may take place.
More specifically, in
FIGS. 1 and 2
, the rotational secondary torque is input from the propeller shaft
101
as indicated by an arrow A, passes through the companion flange
102
, the front bearing
106
, the housing shank
104
and the housing
105
and enters the bearing retainer
121
as indicated by arrows B, C, D, E and F, after which it passes through the needle bearing
124
and acts on the main shaft
108
. Via the same route, the thrust-up load enters the bearing retainer
121
and presses the thrust waster
125
to act on the main shaft
108
.
Description will then be made of a mechanism of leakage of oil through the gap between the rotor
110
and the valve block
118
as a result of input of such a rotational secondary torque. Referring to
FIG. 3
, a hydraulic power transmission torque
127
is coupled to a differential gear
128
. Rear wheels
129
and
130
are disposed on opposed sides of the differential gear
128
. An arrow T indicates an engine torque of the propeller shaft
101
. The engine torque T results in a rotational secondary torque as indicated by an arrow Tsin &thgr; input to the hydraulic power transmission joint
127
. When the rotational secondary torque enters the hydraulic power transmission joint
127
, the main shaft
108
of the joint
127
is subjected as in
FIG. 4
to a bending force due to a reaction force from the differential gear
128
in the tire lock status as indicated by arrows H of the rear wheels
129
and
130
. For this reason, the hydraulic power transmission joint
127
attempts to tilt as indicated by a chain double-dashed line. In effect, however, the hydraulic power transmission joint
127
results by no means in the status of the chain double-dashed line, but instead as in the diagrammatic view of
FIG. 5
the housing
105
and the housing shank
104
tend to have a counterclockwise tilt due to a degree of freedom of vertical movement of the propeller shaft
101
in the attached condition. As a result, the rotor
110
becomes tilted relative to the main shaft
108
as shown in
FIGS. 6 and 7
. In the normal status where input of the rotational secondary torque is absent, the rotor
110
is not tilted relative to the main shaft
108
as in
FIG. 8
but remains parallel. Once the rotational secondary torque is input, however, the rotor
110
becomes tilted relative to the main shaft
108
as in
FIGS. 6 and 7
, resulting in a separation between the rotor
110
and the valve block
118
. For this reason, oil may often leak through the gap between the valve block
118
and the rotor
110
and the hydraulic pressure may be reduced with lowering of the torque.
SUMMARY OF THE INVENTION
It is therefore the object of the present invention to provide a hydraulic power transmission joint capable of suppressing any leakage of oil through the gap between the valve block and the rotor, thereby preventing occurrence of a lowering of torque arising from a reduction of hydraulic pressure, as well as preventing occurrence of abrasions and noises.
According to a first aspect of the present invention there is provided a hydraulic power transmission joint disposed between an input shaft and an output shaft which are capable of relative rotations, for transmitting torque depending on rotational-speed differences between the two shafts, the hydraulic power transmission joint having a housing coupled to the input shaft and having a cam face formed on the inner side of the housing; a rotor coupled to the output shaft and rotatably housed in the housing, the rotor including a plurality of axially extending plunger chambers; a plurality of plungers each accommodated reciprocatively under a pressing force of a return spring in each of the plurality of plunger chambers, the plurality of plungers being operated by the cam face upon relative rotations between the two shafts; a discharge hole formed in the rotor so as to communicate with the plunger chambers; and a valve block having a high-pressure chamber which is in communication with the discharge hole, the valve block having an orifice which generates a flow resistance by the flow of oil discharged by the action of the plungers; wherein the hydraulic power transmission joint comprises a bearing retainer provided adjacent to the valve block and having the outer periphery press-fitted into the interior of the housing, the bearing retainer having on its inside an extension which extends in the axial direction of the output shaft; and a b
Kato Tadahiko
Kusukawa Hirotaka
Murata Shigeo
Shimada Kazuhisa
Takasaki Toshiharu
Fujiunivance Co.
Lorence Richard M.
Wenderoth , Lind & Ponack, L.L.P.
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