Seal for a joint or juncture – Seal between fixed parts or static contact against... – Contact seal for other than internal combustion engine – or...
Reexamination Certificate
2000-04-27
2002-09-03
Knight, Anthony (Department: 3676)
Seal for a joint or juncture
Seal between fixed parts or static contact against...
Contact seal for other than internal combustion engine, or...
C277S635000, C277S637000, C464S173000
Reexamination Certificate
active
06443461
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a sealing apparatus attached to an inner periphery of a boot, which is provided between an inner and an outer element of a universal joint of a propeller shaft and a drive shaft of a vehicle, for example, in order to seal and hold a lubricating agent such as grease therein, and to prevent dust, water or the like from invading from the outside.
2. Description of the Related Art
Conventionally, a universal joint for use in a drive shaft of a vehicle, as illustrated in
FIG. 10
, for example, includes a tripod type constant speed joint comprising a cylindrical outer and an inner element fitted into the outer element. In this universal joint ‘a’, an inner element ‘b’ is provided with a drive shaft ‘d’, a ring shaped member mounted to an end of the drive shaft ‘d’, and three rollers turnably supported, respectively, by three bearings extending in a peripheral direction from the ring shaped member with equal intervals and outwardly in a radial direction. In addition, a three-stripe guide groove formed along an axial direction for housing the three rollers of the inner element ‘b’, respectively, is formed on an inner periphery of an outer element ‘c’. Further, a torque is transmitted between the inner element ‘b’ and the outer element ‘c’ via the three rollers engaged with the guide groove.
On the other hand, a boot ‘e’ mounted across the outer element ‘c’ and the inner element ‘b’ of this universal joint ‘a’ comprises a cylindrical adapter ‘f’ and an expandable flexible boot main body ‘g’ securely fixed to one end of the adapter ° F. The adapter ‘f’ is engaged with an outer periphery of the outer element ‘c’, and the boot main body ‘g’ is engaged with an outer periphery of the drive shaft ‘d’. Further, an O-ring ‘h’ is attached to an annular stepped portion formed on the inner periphery of the adapter ‘f’. In this manner, the boot ‘e’ causes its inside to be held in an airtight manner, a lubricating agent filled therein is prevented from leaking, and dust, water or the like is prevented from invading into the inside.
In the meantime, in the prior art, the O-ring ‘h’ attached to the stepped portion of the inner periphery of the adapter ‘f’ is easily deformed because the shape holding force of the O-ring itself is small, which is caused by flexibility of its forming material. As illustrated if
FIG. 11
, even if a portion is at a normal position of the stepped portion, the other portion is sometimes attached in a state in which it is displaced from the normal portion. If the inner element ‘b’ and the outer element ‘c’ are assembled with each other in such state, the O-ring ‘h’ is geared between surfaces other than a sealing surface of the outer element ‘c’, and sufficient sealing capability cannot be performed.
In addition, in such state, the O-ring ‘h’ easily slips off from the stepped portion Further, in order to prevent the O-ring from deforming when the O-ring ‘h’ is attached to the stepped portion of the adapter ‘f’, it is difficult to hold the O-ring ‘h’ with large elastic force in a radial direction on the inner periphery of the adapter ‘f’. Thus, the holding force of the O-ring ‘h’ to the adapter ‘f’ is small. As a result, even if the O-ring ‘h’ is attached to a normal position, in the case where a shock is applied to the boot ‘e’, the O-ring ‘h’ sometimes slips off from the stepped portion. Thus, the inner element ‘b’ and the outer element ‘c’ are assembled with each other while the O-ring ‘h’ slips off, and the sealing capability will be degraded.
Therefore, assembling work must be performed while it is checked whether or not the O-ring ‘h’ is properly attached to the adapter ‘f’, which has lowered the efficiency of the assembly of the universal joint ‘a’.
SUMMARY OF THE INVENTION
The present invention has been achieved in view of such circumference. It is an object of the present invention to provide a sealing apparatus securely held on an inner periphery of a cylindrical member in a normal state, thereby improving the efficiency of assembly of a member to which the sealing apparatus is attached.
In accordance with the present application, there is provided a sealing apparatus comprising: an elastic member having a sealing portion coming into contact with a sealing surface of a cylindrical member in an airtight manner, and a reinforcing member having the elastic member securely fixed thereto, the sealing apparatus being attached to an inner periphery of the cylindrical member having a stepped portion formed between a small cylinder portion having a predetermined inner diameter and a large cylinder portion having an inner diameter larger than the small cylinder portion, wherein the sealing surface is formed on at least one of an inner surface of the stepped portion and an inner periphery surface of the large cylinder portion, and further, a holding portion press-inserted into the inner periphery of the small cylinder portion is provided so as to hold the reinforcing member on the inner periphery of the cylindrical member.
In this specification, circles such as cylinder, ring, circumference, arc or the like include a substantially circular shape that is a shape close to a circle as well as an exact circular shape. In addition, in the specification, an outer engagement completion close position means a position at which, even if a communication passage is closed at the position, and then, the outer element is relatively moved to an engagement completion position relevant to a boot, the boot does not inflate along with a rise of the air pressure inside of the boot caused by the relative movement, or even if such inflation occurs, the inflation is so slight that it can be substantially ignored.
REFERENCES:
patent: 3468171 (1969-09-01), Macielinski
patent: 4685686 (1987-08-01), Weiler
patent: 5295914 (1994-03-01), Milavec
patent: 6093108 (2000-07-01), Moulinet
patent: 724683 (1995-05-01), None
Hiraga Yoshio
Suka Teiji
Toita Shinya
Orum & Roth
Peavey Enoch E
Snowa Corporation
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