Rotary shafts – gudgeons – housings – and flexible couplings for ro – Shafting – Hollow or layered shaft
Reexamination Certificate
2000-03-28
2001-12-11
Browne, Lynne H. (Department: 3629)
Rotary shafts, gudgeons, housings, and flexible couplings for ro
Shafting
Hollow or layered shaft
C464S079000
Reexamination Certificate
active
06328656
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a propeller shaft for a vehicle, more particularly, to a vehicular propeller shaft capable of absorbing an impact by being deformed axially when an impact load is applied in the longitudinal direction of the vehicle.
2. Prior Art
Generally, a vehicle is constituted so as to transmit engine power from a transmission to a differential through a propeller shaft and from the differential to wheels.
However, the propeller shaft is disposed in the transversal center of the vehicle in the longitudinal direction thereof and therefore, for example, in an event of collision, when a large impact is exerted in the lengthwise direction of the vehicle, the deformation of the vehicle body is blocked by a “lengthwise resistance” of the propeller shaft and as a result a still larger impact is caused in the vehicle.
In order to solve this problem, Japanese Patent Application Laid-open No. Toku-Kai-Hei 5-178105 discloses a technique in which a propeller shaft is shaped into a hollow pipe to raise a torsional rigidity per weight. Also, the propeller shaft has a swelling portion annually formed in the radial direction thereof. When an excessively large impact load is applied to the vehicle, the swelling portion is deformed so that the propeller shaft is released from a state of lengthwise resistance.
As shown in
FIG. 8
, List of Unpatentable Examples of Automobile Technologies No. 95202 published by the Committee of Intellectual Properties of Japan Automobile Manufactures Association, discloses a propeller shaft
100
comprising a hollow propeller shaft
101
, a center support bearing
102
provided at the rear end of the propeller shaft
100
and a bellows pipe
103
connected in the front thereof with the hollow propeller shaft
101
and connected in the rear thereof with the center support bearing
102
. When an axial load is applied to the propeller shaft
100
, the bellows pipe
103
is deformed so that the propeller shaft
100
can be released from the state of lengthwise resistance.
Further,
FIG. 9
a
shows a propeller shaft
111
disclosed by Japanese Patent Application Laid-open No. Toku-Kai-Hei 8-226454. The propeller shaft
111
comprises a female member
112
and a male member
113
spline-fitted to the female member
112
. The female member
112
comprises a small diameter portion
112
a
and a large diameter portion
112
b
and the small diameter portion
112
a
is spline-fitted over the male member
113
. Therefore, a step portion
112
c
is formed on the propeller shaft
111
between the small diameter portion
112
a
and the large diameter portion
112
b.
When an impact load is applied to thus formed propeller shaft
111
in the longitudinal direction, as shown in
FIG. 9
b,
the step portion
112
c
is deformed or broken in the axial direction so as to absorb the impact load.
According to the propeller shaft disclosed in the Patent Application No. Toku-Kai-Hei 5-178105, when a large impact load is applied in the longitudinal direction, first the swelling portion must be deformed in the axial direction. However, the deformation of the swelling portion needs a large initial load and therefore the impact can not be absorbed in a proper and effective way. Further, there occurs so called “collision phenomenon” in which both ends of the swelling portion abut against each other and as a result the propeller shaft can not have an adequate crash stroke. On the other hand, the formation of a plurality of swelling portions leads to a fear of reduced critical speed of the propeller shaft.
In case of the propeller shaft
100
disclosed in List of Unpatentable Examples of Automobile Technologies No. 95202, when an axial load is exerted on the hollow propeller shaft
101
, the bellows pipe
103
is deformed to reduce the lengthwise resistance of the propeller shaft
100
.
However, when the propeller shaft
100
is deformed and shortened, respective tops of the bellows pipe
103
abut against neighboring tops and respective valleys thereof abut against neighboring valleys, that is, “collision phenomenon” is generated. This prevents the propeller shaft
100
from having an adequate crash stroke. On the other hand, an increased number of tops and valleys of the bellow pipe
103
has an adverse effect on the critical speed of the propeller shaft
100
.
According to the propeller shaft
111
disclosed in Toku-Kai-Hei 8-226454, the problem is that since the deformation or breakage in the axial direction requires a large impact load, especially, a large impact load at the initial stage, the propeller shaft
111
still has a difficulty in alleviating the impact effectively.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a vehicular propeller shaft having an adequate crash stroke without decreasing critical speed thereof, this preventing the propeller shaft from having a lengthwise resistance, thereby an effective alleviation of impact can be achieved.
To attain the object, the propeller shaft has a hollow pipe and a bellows section which comprises a small diameter section, a large diameter section whose diameter is larger than the small diameter section, a plurality of swelling sections partially, outwardly swelled, having an enlarged diameter, annularly shaped around the hollow pipe, and consecutively disposed between the small diameter section and the large diameter section and a valley section having a reduced diameter, annularly shaped and disposed between two adjacent swelling sections. The swelling section has a trapezoid cross section constituted by an up-grade surface, a down-grade surface and a top surface provided between said up-grade surface and said down-grade surface.
REFERENCES:
patent: 3487710 (1970-01-01), Fergle
patent: 3754411 (1973-08-01), Orain
patent: 4304147 (1981-12-01), Linnemeier et al.
patent: 4512209 (1985-04-01), Linnemeier
patent: 4531619 (1985-07-01), Eckels
patent: 5503431 (1996-04-01), Yamamoto
patent: 6189919 (2001-02-01), Sinnhuber et al.
patent: 5178105 (1993-07-01), None
patent: 8226454 (1996-09-01), None
List of Unpatentable Examples of Automobile Technologies No. 95202, Mar. 31, 1995, Published by the Committee of Intelectual Properties of Japan Automobile Manufacturers Association.
Tomizawa Hidehisa
Uchikawa Koichi
Binda Greg
Browne Lynne H.
Farber Martin A.
Fuji Jukogyo Kabushiki Kaisha
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