192 clutches and power-stop control – Clutches – Operators
Reexamination Certificate
2002-04-22
2004-01-27
Bonck, Rodney H. (Department: 3681)
192 clutches and power-stop control
Clutches
Operators
C180S233000, C192S101000, C701S034000
Reexamination Certificate
active
06681912
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a driving force distributing apparatus which is applied to a four-wheel drive vehicle and which distributes a driving force from a prime mover to front wheels and rear wheels in predetermined distributing proportions and particularly to a driving force distributing apparatus in which the number of parts is reduced to cut a cost and a capacity is reduced to lessen constraints to a vehicle design without impairing excellent responsivity of a prior-art apparatus.
2. Description of the Related Art
In recent years, as use of automobiles is diversified, more and more four-wheel drive vehicles are used suddenly. In the four-wheel drive vehicle, a driving force distributing apparatus for distributing a driving force generated by an engine to front wheels and rear wheels by a hydraulic multiple disc clutch is used conventionally.
FIG. 7
shows a basic structure of a four-wheel drive vehicle to which the prior-art driving force distributing apparatus is applied. The driving force generated by an engine
101
is transferred to the driving force distributing apparatus
1
through a transmission
102
and a center drive shaft
103
, hydraulic oil at predetermined hydraulic pressure is supplied from a hydraulic pressure unit
5
to a multiple disc clutch
23
built into the driving force distributing apparatus
1
, and the driving force from the engine
101
is transferred to rear wheels
105
through the center drive shaft
103
and a differential
104
and is transferred to front wheels
107
through a front drive shaft
106
and the differential
104
in predetermined distributing proportions. Control of hydraulic pressure to the multiple disc clutch
23
is carried out by controlling the hydraulic pressure unit
5
by the control circuit
6
.
FIG. 8
shows the prior-art driving force distributing apparatus
1
shown in FIG.
7
. The driving force distributing apparatus
1
includes an apparatus main body
2
A, the hydraulic pressure unit
5
connected to the apparatus main body
2
A through a pipe
5
a
, and the control circuit
6
for controlling the hydraulic pressure unit
5
. In the apparatus main body
2
A, the multiple disc clutch
23
, a pressing member
25
for pressing the multiple disc clutch
23
, a lever
13
for pressing the pressing member
25
, and a piston
14
for moving the lever
13
in a rotating manner are disposed.
The hydraulic pressure unit
5
includes an oil pump
50
for pressure-sending the hydraulic oil, a pump motor
51
for driving the oil pump
50
, an accumulator
53
for accumulating a pressure of the hydraulic oil pressure-sent from the oil pump
50
through a check valve
52
, a pressure switch
54
for detecting line pressure, a pressure control valve
56
connected through a filter
55
to control the line pressure, a relief valve
57
for operating at pressure equal to or higher than predetermined pressure to relieve the hydraulic oil, and a reservoir tank
58
for receiving the hydraulic oil returning from the pressure control valve
56
and the relief valve
57
.
In the driving force distributing apparatus
1
formed as described above, if the oil pump
50
pressure-sends the hydraulic oil by driving of the pump motor
51
, the pressure of the hydraulic oil is accumulated by the accumulator
53
and the pump motor
51
is ON/OFF controlled by the pressure switch
54
such that the line pressure is in a predetermined pressure range. A part of the hydraulic oil pressure-sent from the oil pump
50
and controlled to be at pressure in the predetermined pressure range is returned to the reservoir tank
58
according to an opening degree of the pressure control valve
56
controlled by the control circuit
6
. As a result, hydraulic pressure of the hydraulic oil supplied to the piston
14
, i.e., pressure on the multiple disc clutch
23
(clutch pressure) is adjusted. In this manner, by controlling the opening degree of the pressure control valve
56
, the clutch pressure can be controlled further continuously and optimum power distribution can be achieved under various traveling conditions.
However, according to the prior-art driving force distributing apparatus, because many parts are necessary for a hydraulic pressure control mechanism and expensive parts such as a current control pressure regulating valve are included in the parts, the apparatus as a whole is expensive. Because a capacity of the hydraulic pressure unit is large, a place in the vehicle in which the hydraulic pressure unit is mounted is limited. Therefore, the hydraulic pressure unit needs to be disposed in a place at a distance from a transfer and the hydraulic piston on a transfer side and the hydraulic pressure unit need to be coupled by a flexible hydraulic pipe.
Therefore, it is an object of the invention to provide a driving force distributing apparatus in which the number of parts is reduced to cut a cost and a capacity is reduced to lessen constraints to a vehicle design without impairing excellent responsivity of the prior-art apparatus.
SUMMARY OF THE INVENTION
To achieve the above object, according to the present invention, there is provided a driving force distributing apparatus for pressing a multiple disc clutch with a predetermined pressing force by a pressing member to transfer a driving force from a prime mover to a front wheel and a rear wheel in distributing proportions corresponding to the predetermined pressing force, the apparatus comprising: a piston for pressing the multiple disc clutch through the pressing member; a pump for supplying pressure fluid to a piston chamber, the pressure fluid being for generating the pressing force for pressing the pressing member in the piston; a motor for driving the pump for normal rotation to supply the pressure fluid to the piston chamber; pressure fluid discharging means provided to a pressure fluid supply path extending from the pump to the piston chamber to discharge the pressure fluid on a piston chamber side in the pressure fluid supply path to an outside when a pressure difference between pressure on the piston chamber side and pressure on a pump side in the pressure fluid supply path becomes equal to or greater than a predetermined value; and control means for driving the motor for normal rotation to drive the pump for normal rotation in increasing pressure in the piston chamber and for driving the motor for reverse rotation to drive the pump for reverse rotation to make the pressure difference equal to or greater than the predetermined value in reducing the pressure in the piston chamber.
With the above structure, in reducing the pressure in the piston chamber, by driving the pump motor for reverse rotation, the pressure difference between the piston chamber side pressure and the pump side pressure in the pressure fluid supply path increases and the pressure fluid on the piston chamber side in the pressure fluid supply path is instantaneously discharged outside.
REFERENCES:
patent: 4874056 (1989-10-01), Naito
patent: 5119298 (1992-06-01), Naito
patent: 5251719 (1993-10-01), Eto et al.
patent: 5644916 (1997-07-01), Hayasaki
patent: 5819192 (1998-10-01), Wakahara et al.
patent: 6009968 (2000-01-01), Kouno
Geshi Yuzo
Suzuki Satoru
Barnes & Thornburg
Bonck Rodney H.
Conte James B.
Fujiunivance Corporation
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