Driving shaft

Details Driving shaft Driving shaft

1998-11-13

2001-04-17

Browne, Lynne H. (Department: 3629)

Rotary shafts, gudgeons, housings, and flexible couplings for ro

Coupling accommodates drive between members having...

Coupling transmits torque via radially directed pin

C464S007000, C464S179000, C464S183000

Reexamination Certificate

active

06217455

ABSTRACT:

This invention relates to a driving shaft having an inner and an outer tube axially movable but not rotatable relative to each other for transmitting torque therebetween, and more particularly to an improved lubrication of sliding surfaces of the inner and outer tubes.
Such a driving shaft and more particularly the lubrication of sliding surfaces of inner and outer tubes of driving shafts have been disclosed in Japanese Patent Application Opened No. H5-312,219 (1993) which is the prior application of the applicant of the present application.
In the driving shaft disclosed in the Japanese Patent Application Opened No. H5-312,219, for the purpose of lubricating the sliding surfaces of the inner and outer tubes, a grease nipple is provided at the end of the inner tube adjacent the universal joint and connected to grease outlet means provided on the inner tube.
With such a driving shaft disclosed in the prior application, its principal object is to feed grease to sliding surfaces of the inner and outer tubes having a lemon-shaped cross-section. In order to supply the grease to the sliding surfaces continuously, it is needed to inject grease frequently into the grease nipple provided at the end of the inner tube adjacent the universal joint.
With the disclosed driving shaft, moreover, particularly using tubes of a modified, complicated cross-section, for example, butterfly-shaped cross-section, the driving shaft suffers several disadvantages from recessed inclined surfaces participating in torque transmission, which may cause insufficient and unreliable supply of grease.
With the disclosed driving shaft, furthermore, there is a problem in fixing an oiling hose to the inner tube, in that the oiling hose generally tends to be unintentionally detached from its fixed position.
It is therefore an object of the invention to provide a driving shaft making it possible to supply grease to the portions participating in torque transmission with great certainty without frequent supply of grease and to prevent an oiling hose from being unintentionally removed from its fixed position.
In order to achieve this object, the driving shaft according to the invention characterized in that said driving shaft comprises partition means including a pair of partition walls situated on the sides of the proximal and distal ends of the inner tube hermetically sealing at least the inside of the inner tube to define a grease reserving space for grease and a hose mounting portion having an oil hole provided on said partition wall on the side of the proximal end; oiling port means provided on a fitting yoke on the side of the proximal end of the inner tube; oiling conduit means connecting said hose mounting portion of said partition means and said oiling port means; and distribution passage means for distributing the grease from said grease reserving space to the portions of sliding surfaces of said inner and outer tubes which participate in torque transmission.
With this construction according to the invention, the grease reserved in the grease reserving space is supplied from the partition means through the distribution passage means to the sliding surfaces of the inner and outer tubes participating in torque transmission for a long period of time, thereby reducing the thrust or frictional resistance and noise when rotating and considerably prolonging the service life of the driving shaft.
In a preferred embodiment of the invention, the partition means comprises a container made of a plastic material having a cross-section of a similar figure to that of said inner tube and a size to be fitted in said inner tube by press-fitting, and said hose mounting portion is an elongated projection extending from said partition wall on the side of the proximal end of the inner tube toward said proximal end, and wherein said distribution passage means comprises a plurality of elongated grooves extending in the longitudinal direction of said container and formed in the side wall of said container corresponding to the shaped portions of said inner tube participating in torque transmission, and a plurality of through-holes formed in said inner tube to communicate with said elongated grooves. With this construction, the grease reserving space is advantageously provided only by inserting the container into the distal end of the inner tube, thereby simplifying the assembling of the driving shaft.
In this embodiment, if the container is formed so as to be slightly tapered in its longitudinal direction, the insertion of the container into the inner tube becomes easier and an unintentional removal of the container from the inner tube can be prevented. Moreover, if the container is provided with at least one annular protrusion on its outer circumference, the fixation of the container in the inner tube becomes more reliable with the aid of the frictional engagement of the annular protrusion.
In another preferred embodiment of the invention, the partition means comprises a pair of partition walls press-fitted in said inner tube, and said distribution passage means comprises a plurality of through-holes formed in said inner tube at its shaped portions participating in torque transmission. With this construction, there is no need for preparing a container to form a grease reserving space. If the partition walls are made of a plastic material, they can be more easily press-fitted into the inner tube and become more inexpensive.
In a further preferred embodiment of the invention, the oiling port means comprises an inlet side hose support which is able to be fixed to said fitting yoke supporting the proximal end of said inner tube and has an oiling protrusion, a hose receiving recess and an oiling passage communicating said oiling protrusion with said hose receiving recess, and said hose mounting portion comprises an outlet side hose support which is able to be fixed to said partition wall on the side of the proximal end and has a hose receiving recess and an oiling passage communicating said hose receiving recess with said grease reserving space, and wherein said oiling conduit means comprises a hose whose both ends are to be inserted into said hose receiving recesses of said inlet and outlet side hose supports, respectively and having radially extending flanges, respectively, and hose fixing plugs which are able to be fixed in said hose receiving recesses of said inlet and outlet side hose supports, respectively, for fixing said both ends of the hose in said receiving recesses, respectively. With this construction, the unintentional removal of the hose from its fixed position can be surely prevented.
In this embodiment, each of said flanges at both the ends of said hose is provided on its end face with an annular protrusion or annular recess, while each of said hose supports is correspondingly provided in the bottom face of the hose receiving recess with an annular recess or annular protrusion engaging said annular protrusion or annular recess. With this construction, the sealing between the hose and the oiling passage becomes improved.
The invention will be more fully understood by referring to the following detailed specification and claims taken in connection with the appended drawings.


REFERENCES:
patent: 3105370 (1963-10-01), Weasler
patent: 5173082 (1992-12-01), Bondioli
patent: 5366043 (1994-11-01), Kretschmer et al.
patent: 5538474 (1996-07-01), Kretschmer et al.
patent: 19712158 (1998-10-01), None
patent: 0916856A2 (1999-05-01), None
Patent Abstracts of Japan, vol. 1997, No. 2, Feb. 28, 1997, JP 08 254217 A (Matsui), Oct. 1, 1996.
Patent Abstracts of Japan, vol. 1997, No. 2, Feb. 28, 1997, JP 08 254216A (Matsui), Oct. 1, 1996.

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