Joints and connections – Interfitted members – Longitudinally splined or fluted rod
Reexamination Certificate
1999-07-01
2001-07-31
Kim, Harry C. (Department: 3629)
Joints and connections
Interfitted members
Longitudinally splined or fluted rod
C403S374500, C403S359200, C074S492000, C280S775000
Reexamination Certificate
active
06267528
ABSTRACT:
This application claims the benefit of Japanese Patent Applications No. 10-212029 and 11-79040 which are hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a coupling structure of a variable length shaft used for a steering device etc of an automobile, and more particularly to a coupling structure of a variable length shaft capable of enhancing a workability when assembling the steering device into a vehicle and surely preventing a “backlash” from being caused after having incorporated the steering device.
2. Related Background Art
A steering device of an automobile is structured such that an intermediate shaft of a steering shaft is contractible upon a collision etc of the vehicle, thus protecting the driver. More specifically, the intermediate shaft of the steering shaft is spline- or serration-fitted to a pipe member provided posterior to the intermediate shaft, and when the collision happens, the intermediate shaft is retracted into the pipe member.
On such spline-fitting or the like, a “backlash” might occur to some extent between the intermediate shaft and the pipe member due to factors such as a limit of working accuracy etc.
Japanese Utility Model Post-Exam Publication No. 63-17862 discloses a structure for preventing the “backlash” described above, wherein an end of a pipe member is capable of expanding and diminishing in diameter in a radial direction by forming a plurality of slits in the end of the pipe member, an intermediate shaft is spline-fitted in this pipe member, thereafter a ring member is fitted to an outer periphery of the end of the pipe member, and the end of the pipe member is fastened against the intermediate shaft, thereby preventing the above “backlash”.
Before assembling the steering device into the vehicle, however, as disclosed in the above Publication, if the “backlash” is prevented by previously fastening the end of the pipe member with the ring member, a slide frictional resistance in an axial direction between the intermediate shaft and the pipe member increases on the contrary, in assembling the steering device into the vehicle. This might lead to a difficulty of adjusting lengths of the intermediate shaft and the pipe member in the axial direction and to a decline of workability.
Under such circumstances, it is desired that the workability be enhanced, when assembling the steering device into the vehicle, by enabling the intermediate shaft to move in the axial direction along inside the pipe member, and the occurrence of the “backlash” be prevented with certainty after having assembled the steering device.
SUMMARY OF THE INVENTION
It is a primary object of the present invention, which was devised in view of the circumstances described above, to provide a coupling structure of a variable length shaft capable of enhancing a workability when assembling a steering device into a vehicle, and surely preventing an occurrence of the “backlash” after having assembled the steering device.
To accomplish the above object, a coupling structure of a variable length shaft comprises a pipe member having its end capable of expanding and diminishing in diameter by forming with a plurality of slits in the end thereof, an intermediate shaft spline-fitted in the pipe member, and a ring member fitted to an outer periphery of the end of the pipe member, the intermediate shaft being fastened by the outer periphery of the end thereof, wherein a holder is attached to an end of the ring member, a slide frictional resistance of the pipe member against the intermediate shaft is reduced by expanding a diameter of the ring member, the ring member, after assembled, diminishes in diameter by releasing the holder, and a fastening force of the pipe member on the intermediate shaft is increased with a fastening force of the ring member which acts with the diametrical reduction of the ring member.
Thus, according to the present invention, for example, when assembling the steering device into the vehicle, the holder is attached to the end of the ring member, and the slide frictional resistance of the pipe member against the intermediate shaft is reduced by expanding the diameter of the ring member. It is therefore possible to make the intermediate shaft slidable on the pipe member and enhance the workability when assembling.
While on the other hand, for example, after having incorporated the steering device into the vehicle, the holder is released, and the ring member diminishes in diameter. Then, the fastening force of the pipe member upon the intermediate shaft can be increased with the fastening force of the ring member which acts with the diametrical reduction thereof. It is therefore possible to surely prevent the “backlash” derived from factors such as a working accuracy of the spline fitting. Further, the holder is released simply by the finger of the worker without using a tool etc, thereby obtaining a high workability of releasing the holder.
REFERENCES:
patent: 3179450 (1965-04-01), Recker
patent: 4728218 (1988-03-01), Durham
patent: 5006007 (1991-04-01), Fischer et al.
patent: 5013177 (1991-05-01), Sol
patent: 5562307 (1996-10-01), Conner
patent: 5707167 (1998-01-01), Battocchio
patent: 5732600 (1998-03-01), Peterson et al.
patent: 5816113 (1998-10-01), Fohl
patent: 6105456 (2000-08-01), Higashino et al.
patent: 63-17862 (1988-05-01), None
patent: 2-44609 (1990-11-01), None
patent: 4-131578 (1992-12-01), None
Kim Harry C.
Miles & Stockbridge P.C.
NSK Ltd.
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