192 clutches and power-stop control – Clutches – Progressive engagement
Reexamination Certificate
2000-01-12
2001-11-13
Bonck, Rodney H. (Department: 3681)
192 clutches and power-stop control
Clutches
Progressive engagement
C192S054520
Reexamination Certificate
active
06315099
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a driving force transmission system to be applied to a transmission, transfer or differential of a vehicle.
2. Related Art
Generally in the driving force transmission system of the vehicle, there are arranged a plurality of rotary members, through which the output of an engine is transmitted to wheels. When a clutch mechanism is arranged in the driving force transmission system between the rotary members, on the other hand, the transmission/interruption of a torque can be arbitrarily switched by applying/releasing the clutch mechanism, if necessary. One example of the driving force transmission system, in which the clutch mechanism is arranged in the torque transmission path of the rotary members, is disclosed in Japanese Patent Laid-Open No. 282019/1991 (JP-A-3-282019).
The driving force transmission system, as disclosed, is equipped with a differential carrier made hollow, a connecting shaft (or a first rotary member) inserted in the differential carrier, and a hub (or a second rotary member) arranged in the differential carrier and made rotatable relative to the connecting shaft. The connecting shaft and the hub are arranged on an axis, and a bearing is fitted between the differential carrier and the connecting shaft.
On the differential carrier, on the other hand, there is fitted an annular electromagnet which is stopped in its rotation relative to the differential carrier by means of bolts. On the connecting shaft, moreover, there is fixed a cylindrical side wall to set a predetermined air gap between the side wall and the electromagnet. A drum is jointed to the outer circumference of the side wall, and a pilot clutch and a main clutch are arranged between the drum and the hub.
The pilot clutch is equipped with a clutch disc splined in the inner circumference of the drum, a cam member fitted axially movably on the outer circumference of the hub, a clutch plate splined in the outer circumference of the cam member, and an armature to be attracted toward the side wall by an electromagnetic force. On the other hand, the main clutch is equipped with a clutch disc splined in the inner circumference of the drum, and a clutch plate splined in the flange of the hub.
Between the cam member and the main clutch, moreover, there is arranged an axially movable push member. Between the cam member and the push member, still moreover, here are fitted balls. On the other hand, a drive pinion shaft is jointed to the hub, and the drive pinion shaft is jointed to the differential constructed by the gear mechanism.
According to the driving force transmission system thus constructed, when no electric current is fed to the electromagnet, the pilot clutch is released so that the torque of the connecting shaft is not transmitted to the hub. When the electric current is fed to the electromagnet, on the other hand, the magnetic flux passes through the side wall and the armature so that the armature is attracted toward the side wall by the electromagnetic force.
Then, the pilot clutch is applied to rotate the cam member, and this rotation is transmitted to the balls so that the push member is activated in the axial direction to apply the main clutch thereby to transmit the torque of the connecting shaft to the hub. The torque thus transmitted to the hub is transmitted through the drive pinion shaft, the differential and axles to the wheels.
On the other hand, the differential carrier is filled in its internal space with oil for lubricating and cooling the pilot clutch, the main clutch and the differential.
Here, in the pilot clutch or the main clutch, the torque is transmitted by the frictional force between the surfaces of the clutch disc and the clutch plate. It is, therefore, preferable to select the oil which can keep the wear resistance, the oil cutting property or the judder resistance of the clutch disc and the clutch plate satisfactory. In the differential, on the other hand, the torque is transmitted and differentiated by the meshing resistance of the gears. It is, therefore, preferable to select the oil which is low in the fluid point, and is excellent in the heat resistance and oxidation stability and load resistance.
In the driving force transmission system described in the aforementioned publication, however, the pilot clutch, the main clutch and the differential are arranged in a common space of the differential carrier. This makes it difficult to employ the oil which is suited individually for the pilot clutch, the main clutch and the differential. As a result, the active characteristics of the pilot clutch and the main clutch may be degraded to lower the transmission function of the driving force.
Moreover, the oil, as confined in the differential carrier, may wet the electromagnet to make the magnetic permeability of a magnetic circuit heterogeneous and to lower the transmission function of the clutch mechanism for the driving force. Still moreover, a foreign substance such as wear powder, as produced at the side of the differential, may enter the clearance between the clutch disc and the clutch plate to wear or break the clutch mechanism thereby to lower the durability or the transmission function of the driving force.
SUMMARY OF THE INVENTION
A main object of the invention is to provide a driving force transmission system capable of using the oil suited for the action characteristics of a clutch mechanism and sealing the clutch mechanism to be controlled by an electromagnet, from another mechanism.
Another object of the invention is to improve the accuracy of a gap to be formed between an electromagnet and a magnetic member.
Still another object of the invention is to reduce the number of parts of the driving force transmission system.
Still another object of the invention is to facilitate the handling of an electric wire for energizing the electromagnet.
Still another object of the invention is to improve the positioning accuracy of a first rotary member in the radial direction.
Still another object of the invention is to make it possible to mount the driving force transmission system on a vehicle such that it is arranged in a longitudinal intermediate portion of the propeller shaft.
Still another object of the invention is to prevent the vibration at the vehicle body side from being transmitted to the electromagnet.
Still another object of the invention is to make it possible to mount the driving force transmission system on the vehicle without any special case and to arrange the same without modifying the transfer or differential.
Still another object of the invention is to suppress the entrance of a foreign substance into an electromagnet housing chamber.
Still another object of the invention is to improve the durability of a clutch mechanism.
Still another object of the invention is to facilitate the positioning of an annular electromagnet and a casing relative to each other in the circumferential direction.
Still another object of the invention is to suppress the plastic deformation of a first rotary member or nuts when stud bolts are embedded in the first rotary member and when the nuts are fastened after a fitting member is attached.
Still another object of the invention is to enhance the action efficiency for the clutch mechanism of the driving force transmission system of this kind by preventing the leakage of a magnetic flux establishing a magnetic path and to improve the controllability of the electromagnet for the clutch mechanism by preventing the fluctuation of the magnetic flux density in the magnetic path.
Still another object of the invention is to reduce the weight of the driving force transmission system.
Still another object of the invention is to enhance the applying force for the clutch mechanism thereby to increase the torque to be transmitted between the first rotary member and the second rotary member.
Still another object of the invention is to promote the cut of an oil film to be formed between a clutch plate composing the clutch mechanism and an armature or magnetic
Ashida Satoshi
Hosokawa Takashi
Ichikawa Akihiko
Ikeda Akihiko
Isomura Moritaka
Bonck Rodney H.
Ho Ha
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Toyota Jidosha & Kabushiki Kaisha
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