Planetary gear transmission systems or components – With lubricaton – For differential planetary gearing
Reexamination Certificate
2000-04-10
2002-07-02
Marmor, Charles A (Department: 3681)
Planetary gear transmission systems or components
With lubricaton
For differential planetary gearing
C475S231000
Reexamination Certificate
active
06413183
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a power transmission apparatus employed for an automobile, and more particularly to a power transmission apparatus used in a torque transmitting passage, for example, in a middle of a shaft connecting right and left road wheels and in a middle of a shaft between a front road wheel and a rear road wheel.
2. Description of Relevant Art
In recent years, in a front engine front drive vehicle (FF vehicle), a differential gear having a torque sensitive type limited slip differential function has been reconsidered. When the vehicle is provided with this equipment, a lot of advantageous features can be obtained, for example, a motion performance,of a vehicle is improved, that is, a handling performance is improved, a response against a stepping down operation of an accelerator pedal is improved, a stability of a vehicle motion is improved and the like, so that a mounting rate is increased.
Japanese Patent Publication No. 46-8206 is related to a bevel gear type differential gear.
A differential gear is rotatably supported to a differential carrier (not shown) in boss portions at both ends of a differential case. An inner portion of the differential case is lubricated by an oil in an oil reservoir provided in the differential carrier.
A differential gear mechanism is constituted by a pinion shaft fixed to the differential case, a pinion gear rotatably supported on the pinion shaft and a pair of oppositely arranged side gears meshing with the pinion gear, and the side gears are movably connected to axles, respectively.
Further, clutch members in a pressing side are movably connected onto the axles adjacent to a back surface of each of the side gears and a clutch member in a pressure receiving side is fixed to an inner wall of the differential case. A corn clutch is constituted by both clutch members, thereby performing a limited slip differential operation.
A large opening for assembling the differential gear mechanism and the corn clutches is provided in a cylindrical wall portion of the differential case, and the opening also constitutes a port for a lubricating oil.
However, in general, a housing for accommodating the differential gear is commonly used with a housing for a transmission, and in this case, a lubricating oil of the differential gear is commonly used with that of the transmission. Among the lubricating oil, an AT oil employed for an automatic transmission has a viscosity lower than that of an MT oil employed for a manual transmission, and commonly serves as a working fluid for a hydraulic torque converter. This structure is provided for reducing a frictional loss of the oil flow passage. Further, the viscosity of the AT oil is reduced in the case of being employed for operating the hydraulic actuator. This structure is provided for normally operating the actuator even under a condition that the oil temperature is low.
Further, the AT oil contains an extreme pressure agent. This is provided for improving an abrasion resistance of a drive transmitting surface having a high surface pressure, for example, between a pulley and a belt of a continuously variable transmission (CVT).
Since the differential gear is arranged in a portion after a final reduction of an engine speed under a condition of being dip-feed lubricated by the lubricating oil, a torque corresponding to some times a drive torque transmitted from the engine to the transmission is transmitted. Accordingly, a great force is applied to the slide friction surface and a lubricating oil film can not be kept.
Japanese Utility Model Application Laid-Open (JU-A) No. 5-25038 relates to a sealed type coupling.
A coupling is arranged between a front road wheel and a rear road wheel of a four wheel drive vehicle and distributes a drive force to the front and rear road wheels in correspondence to a difference of a rotational speed generated between the front and rear road wheels. A vane pump is arranged between an input shaft and an output shaft. That is, a rotor of the vane pump is spline connected to the input shaft in the front road wheel side and integrally rotates. On the contrary, a casing is connected to the output shaft in the rear road wheel side and a cam ring is fixed to the casing and integrally rotates with the output shaft.
When the difference of the rotational speed is generated between the front and rear road wheels, the vane pump performs a pump operation together with a relative rotation between the rotor and the cam ring. Accordingly, a hydraulic pressure is generated in correspondence to the difference of the rotational speed between both of the shafts and operates so as to restrict the relative rotation between both of the shafts (between the front and rear road wheels).
At a time of operating the vane pump, the oil in the oil tank provided in the periphery of the casing circulates between the inner portion of the oil tank and the vane pump. The circulating oil is cooled by air within the tank, whereby an abrasion and a seizure of the vane pump are prevented.
SUMMARY OF THE INVENTION
However, when an amount of the lubricating oil is not sufficient, the lubricating oil does not sufficiently spread around an engagement portion of the gear, a friction of the engagement portion is increased and a durability of the parts is reduced. Further, a temperature of the lubricating oil is increased, and the lubricating oil is deteriorated. Further, when the viscosity of the lubricating oil is reduced and the great force is applied, the slide lubricating oil film is not kept. Further, an abraded powder generated from the engagement portion of the gear or the like prevents the lubricating oil from flowing, and particularly, reduces a durability of the engagement portion.
A first object of the present invention is to provide a power transmission apparatus in which a lubricating oil suitable for an element constituting an apparatus is used.
A second object of the present invention is to provide a power transmission apparatus which improves a durability of an element constituting an apparatus.
A third object of the present invention is to provide a power transmission apparatus which secures a cooling performance of a lubricating oil.
A fourth object of the present invention is to provide a power transmission apparatus which secures a flowability of a lubricating oil.
A fifth object of the present invention is to provided a power transmission apparatus which improves a durability of an element constituting an apparatus without increasing a size and a weight of the apparatus.
In order to achieve the objects mentioned above, in accordance with the present invention, there is provided a power transmission apparatus employed for a drive train of a vehicle, in which the following features are provided. That is, an outer rotational member has an inner wall surface and an outer wall surface. An inner rotational member is arranged inside the outer rotational member. Friction-clutch means is provided between the inner rotational member and the outer rotational member and is fastened by a thrust force. An oil lubricates at least the friction-clutch means. An oil space intervenes between the inner rotational member and the outer rotational member. Seal means seals the oil in the oil space. A first oil reservoir is recessed on the inner wall surface of the outer rotational member toward a side of the outer wall surface side.
In this case, “the power transmission apparatus” includes, for example, a differential gear mounted in a middle of a shaft connecting drive road wheels and a coupling mounted in a middle of a shaft between a front road wheel and a rear road wheel. Further, a cone clutch type, a structure having a multi disc clutch or a parallel shaft type limited slip differential system is desirable for the differential gear.
“The outer and inner rotational member” includes a member directly or indirectly rotated by the torque. The outer rotational member is, for example, a housing. The inner rotational member includes, for example, a gear conn
Inose Hideyuki
Ishikawa Osamu
Ishikawa Yasuhiko
Kawata Kazutaka
Mashiyama Akihiro
Marmor Charles A
Tochigi Fuji Sangyo Kabushiki Kaisha
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