Water pump bearing

Details Water pump bearing Water pump bearing

2002-12-11

2004-11-02

Footland, Lenard A. (Department: 3682)

Bearings

Rotary bearing

Antifriction bearing

C384S486000

Reexamination Certificate

active

06811316

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a water pump bearing to be used for a water-cooled engine of an automobile or the like.
DESCRIPTION OF THE RELATED ART
Referring to
FIG. 6
, in a conventional water pump for a water-cooled engine of an automobile or the like, an impeller is attached to an end portion of a pump shaft
53
and a pulley
52
is attached to the other end portion thereof respectively, so that the pulley
52
causes the impeller
51
to rotate, to thereby circulate cooling water. For fixing such a water pump, as shown in
FIG. 6
, generally a water pump bearing is press-fixed in a water pump housing
50
fixed to a main body of the engine. With the water pump bearing, the pump shaft
53
provided with the impeller
51
at an end portion thereof and the pulley
52
at the other end portion thereof respectively is rotatably attached to an outer ring
54
of the bearing with a rolling member
55
located therebetween.
Between the outer ring
54
and the pump shaft
53
, a mechanical seal
57
is provided for sealing a space
58
between the pump housing
50
and the pump shaft
53
to isolate from the impeller
51
.
Also, seal structures are respectively provided at the end portions of the outer ring
54
, for sealing a space therewithin. Among the seal structures, a seal structure
56
on the impeller side is generally constituted of a metal ring reinforcement and an elastic member reinforced by the ring reinforcement.
In such water pump in the public domain, when sealing effect of the mechanical seal
57
is deteriorated because of chronological transition etc., cooling water may penetrate from the impeller
51
side of the seal
57
into the space
58
between the pump housing
50
and the pump shaft
53
.
In addition, the seal structure
56
on the impeller side is repeatedly heated and cooled each time the engine is started and stopped, causing repeated expansion and contraction of air inside the bearing, for which the sealing effect is prone to be damaged.
Accordingly, the cooling water that has penetrated into the space
58
between the pump housing
50
and the pump shaft
53
in the above described manner, or vapor generated from heating the cooling water may penetrate into the internal area of the bearing through the seal structure
56
.
Such penetration of moisture into the internal area of the bearing causes a breakdown of the water pump because of deterioration of grease filled inside the bearing or rust produced inside the bearing, shortening a life span of the water pump.
Moreover, the grease may flow out of the internal area of the bearing through the seal structure
56
, at which the sealing effect of it has been deteriorated by the aforementioned reasons. The outflow of the grease increases friction between the rolling member
55
and the pump shaft
53
, which leads to a breakdown of the water pump bearing, and consequently to a shorter life span of the water pump.
OBJECTS OF THE INVENTION
In view of the foregoing problems with the prior art, it is an object of the present invention to provide a water pump bearing that can prevent penetration of cooling water or moisture into an internal area of the water pump bearing, and outflow of grease from the internal area of the bearing.
SUMMARY OF THE INVENTION
For achieving the object, a water pump bearing according to the invention is constituted as follows.
The water pump bearing comprises, like conventional ones, a pump shaft provided with an impeller at one end portion thereof and a pulley at the other end portion thereof respectively, rotatably attached to an outer ring of the bearing with at least one rolling member located therebetween, and seal structures provided at both end portions of the outer ring for sealing an internal area of the bearing.
Also, there is a seal structure on a side of the impeller, among the seal structures provided at both end portions of the outer ring for sealing the internal area of the bearing, comprises the following characteristic constitution.
The seal structure of a first embodiment comprises a ring-shaped first seal unit having an outer circumferential portion fixed to an inner circumferential portion of the outer ring and an inner circumferential portion in sliding-contact with an outer circumferential surface of the pump shaft. As shown in
FIG. 1
, in the seal structure of the first embodiment, a ring-shaped second seal unit is disposed at an axially outer position from the first seal unit. And, the second seal unit has its inner circumferential portion fixed to an outer circumferential portion of the pump shaft and its outer circumferential portion in sliding-contact with the outer ring.
The first seal unit comprises a ring reinforcement and an elastic member reinforced by the ring reinforcement. An outer circumferential portion of the first seal unit is press-fitted in a fitting groove formed on an inner circumferential surface of the outer ring. A portion of the elastic member further extends from an end portion of the ring reinforcement on the pump shaft side toward the pump shaft for making sliding-contact with an outer circumferential surface of the pump shaft. That portion of the elastic member comprises a first lip portion extending diagonally in an axially inward direction to make sliding-contact with an outer circumferential surface of the pump shaft, and a second lip portion extending diagonally in an axially outward direction to make sliding-contact with an outer circumferential surface of the pump shaft.
The second unit comprises a ring reinforcement having a cylindrical portion extending in an axial direction and fixed to the pump shaft and a flange portion extending from the cylindrical portion toward the outer ring, and an elastic member reinforced by the ring reinforcement. A portion of that elastic member further extends from the outer ring side end portion of the flange portion of the ring reinforcement toward the outer ring comprises a third lip portion in sliding-contact with an axially outer end face of the outer ring.
In the seal structure of a second embodiment, as shown in
FIG. 2
, a portion of the elastic member which constitutes the second seal unit is like the first seal structure, but a portion of that elastic member further extends from the outer ring side end portion of the flange portion of the ring reinforcement toward the outer ring further comprises a fourth lip portion extending diagonally in an axially inward direction to form a non-contact labyrinth seal portion between an axially outer lateral face of the first seal unit.
In the seal structure of a third embodiment, as shown in
FIG. 3
, a ring reinforcement and an elastic member which constitute the second seal unit are like those of the first seal structure or the second seal structure, but a cylindrical portion of a ring reinforcement further has a reinforcing ring extending from the cylindrical portion toward radially inner direction along an axially outer end face of the pump shaft, and a portion of an elastic member existing at the side of radially inner part of it and reinforced by the said reinforcing ring comprises a fifth lip portion in sliding-contact with the axially outer end face of the pump shaft.
In the seal structure of the fourth embodiment, as shown in
FIG. 4
, the second seal unit is like the first embodiment of a seal structure. It comprises a ring reinforcement and an elastic member reinforced by the ring reinforcement. The inner circumferential portion of the second seal unit is press-fitted in a fitting groove formed on an outer circumferential surface of the pump shaft. A portion of the elastic member further extends from the outer ring side end portion of the ring reinforcement toward the outer ring so as to form a third lip portion in sliding-contact with an axially outer end face of the outer ring.
In the seal structure of the fifth embodiment, as shown in
FIG. 5
, a portion of the elastic member constituting the second seal unit is like the fourth seal structure, but a portion of that elastic member further extends from

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