Motor vehicles – Transmission mechanism – With particular drive coupling
Reexamination Certificate
2000-09-05
2002-10-22
Dickson, Paul N. (Department: 3616)
Motor vehicles
Transmission mechanism
With particular drive coupling
C180S384000, C464S153000, C464S154000, C464S182000, C403S359500
Reexamination Certificate
active
06467565
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a shaft drive type power transmission, particularly to a shaft drive type power transmission intended to simplify the connection between a propeller shaft and a pinion gear supported by a gear case.
2. Background Art
A prior art connection structure of a shaft drive type power transmission in which a propeller shaft is connected to a pinion gear via a joint “b” is shown in FIG.
11
. As shown in
FIG. 11
, a boss “d” of a pinion gear “c” is splined-connected to one end of the joint “b”, and the joint “b” is integrated with the pinion gear “c” by fastening a nut “f” to a thread portion “e” formed on the boss “d”. In this way, the joint “b” is sub-assembled with the pinion gear “c” on the gear case side. It should be noted that at this connection step, one end of the joint “b” is butted to a bearing “h” for rotatably supporting the pinion gear “c”.
A propeller shaft “a” is then spline-connected to the other end of the joint “b”, and one end of a boot “g” having the other end previously fixed to the outer periphery of one of the propeller shaft “a” and the joint “b” is fixed to the outer periphery of the other of the propeller shaft “a” and the joint “b”. This type of connection structure has been disclosed, for example, in Japanese Patent Publication No. Sho 63-6399.
FIG. 12
is a view showing a prior art connection structure on the rear wheel side. Like the above connection structure, a joint “n” is fixed to a boss “j” of a pinion gear “i” by fastening a nut “k” to a threaded portion formed on the boss “j.” In
FIG. 12
, character “m” designates a rear end portion of a rear wheel side drive shaft spline-connected to the joint “n”, and “p” is a spring.
According to the above-described prior art, since the joint “b” is sub-assembled with the pinion gear “c” on the gear case side by using a nut “f”, the boot “g” must be mounted, after the propeller shaft “a” is connected to the joint “b.” Since the joint “b” is sub-assembled with the pinion gear “c” on the connection portion between the propeller shaft “a” and the joint “b,” it is difficult to mount the boot “g” on the connection portion between the propeller shaft “a” and the joint “b”. Also, since the joint “b” is fixed to the pinion gear “c” by using the nut “f”, the boss of the pinion gear “c” to which the nut “f” is to be fastened must be threaded. This inherently increases the number of manufacturing steps and the required number of parts.
SUMMARY OF THE INVENTION
The present invention overcomes the shortcomings associated with the prior art and achieves other advantages not realized by the prior art.
Accordingly, it is an object of the present invention to provide a connection between a pinion gear and a propeller drive shaft that is simplified in construction, relatively easily maintained, requires few assembling steps, and ensures solid, reliable connection between mating parts.
It is a further object of the present invention provide a leading end of the joint abutted to a stepped portion of the pinion gear.
It is a further object of the present invention to reduce the requirements of the pinion gear from compensating for axial forces.
These and other objects are accomplished by a shaft drive power transmission for a vehicle in which a propeller drive shaft is connected to a pinion gear on a gear case side of the propeller drive shaft, said transmission comprising a boss of said pinion gear having at least a first diameter portion, a second diameter portion and a third diameter portion, wherein said third diameter portion is larger in diameter than said second diameter portion and said second diameter portion is larger in diameter than said first diameter portion and said first diameter portion is adjacent to said propeller drive shaft; a joint for connecting the pinion gear to the propeller drive shaft, said joint having a shaft end and a pinion end, wherein said shaft end of said joint is operatively spline-connected to said propeller shaft with a spline connection and said pinion end of said joint is operatively spline-connected to said third diameter portion of said boss of said pinion gear with a spline connection and in such a manner as to be integrally connected and rotatable therewith, and wherein the joint is prevented from slipping off of the boss of said pinion gear.
These and other objects are also accomplished by a shaft drive power transmission for a vehicle, said transmission comprising an output shaft transmitting power from a power unit of the vehicle; a front wheel propeller shaft connected to a front end of said output shaft; a right front wheel axle and a left front wheel axle; a front wheel drive case; a pinion gear for distributing drive forces from said front wheel propeller shaft to said right and left front wheel axles; and a boss of said pinion gear having at least a first diameter portion, a second diameter portion and a third diameter portion, wherein said third diameter portion is larger in diameter than said second diameter portion and said second diameter portion is larger in diameter than said first diameter portion; a joint for connecting the pinion gear to the propeller drive shaft, said joint having a shaft end and a pinion end, wherein said shaft end of said joint is operatively spline-connected to said propeller shaft with a spline connection and said pinion end of said joint is operatively spline-connected to said third diameter portion of said boss of said pinion gear with a spline connection and in such a manner as to be integrally connected and rotatable therewith, and wherein the joint is prevented from slipping off of the boss of said pinion gear.
According a first aspect of the present invention, since the joint is fitted to the pinion gear in such a manner as to be integrally rotatable therewith and not to be slipped off therefrom, it is possible to sub-assemble the joint with the propeller shaft, and hence to simplify the assembling process. Further, since it is possible to eliminate the need of fastening the joint to the pinion gear by using a nut as in the prior art structure, it is possible to eliminate the need of threading the boss of the pinion gear and hence to reduce the number of the machining steps and also reduce the number of parts by omitting the nut.
According to a second aspect of the present invention, since the outer periphery of the connection portion between the joint and the propeller shaft is covered with the boot at the step of sub-assembling the joint to the propeller shaft, it is possible to eliminate the need of mounting the boot while connecting the propeller shaft to the pinion gear as in the prior art structure, and hence to omit such a difficult mounting step from the assembly process.
According to a third aspect of the present invention, since the leading end of the joint is abutted to the stepped portion of the pinion gear, the bearing for rotatably supporting the pinion gear can be configured as a common small-sized bearing, thereby resulting in a reduction in the material cost.
According to a fourth aspect of the present invention, since the teeth of the pinion gear are each formed with a straight shape, a reaction force applied upon acceleration/deceleration is, unlike the prior art bevel gear, transmitted not in the axial direction but substantially in the rotational direction. Since the reaction force does not act as a load applied in the axial slip-off direction, it is possible to omit the provision of the nut of the prior art.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
REFERENCES:
patent: 3531144 (1970-09-01), Bizilia
patent: 38
Handa Akio
Seki Bunzo
Birch & Stewart Kolasch & Birch, LLP
Dickson Paul N.
Honda Giken Gokyo Kabushiki Kaisha
Ilan Ruth
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