Rotary kinetic fluid motors or pumps – With lubricating – sealing – packing or bearing means having... – For shaft sealing – packing – lubricating or bearing means
Reexamination Certificate
2001-11-21
2002-11-26
Verdier, Christopher (Department: 3745)
Rotary kinetic fluid motors or pumps
With lubricating, sealing, packing or bearing means having...
For shaft sealing, packing, lubricating or bearing means
C415S111000, C415S168200, C415S229000, C415S230000, C415S231000, C277S394000, C277S423000, C277S551000, C277S560000, C277S562000, C384S478000, C384S485000, C384S486000
Reexamination Certificate
active
06485256
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
This invention relates to a seal apparatus for a water pump and a rotation-support apparatus for a water pump and a water pump, and more particularly to improvement of the seal apparatus of a water pump that is used for circulating coolant water for an automobile engine.
BACKGROUND TECHNOLOGY
A water pump used for circulating coolant water for an automobile engine has been disclosed in Japanese Patent Publication No. Toku Kai Hei 8-254213, and is constructed as shown in
FIG. 4. A
cylindrical housing
1
has an installation flange
2
formed around its outer peripheral surface on the inside end (the inside with reference to the axial direction is the side nearest the engine, and is the right side in all of the figures) and fastened to the cylinder block of the engine by way of the installation flange
2
. Provided on the radial inside of the housing
1
is a rolling-bearing unit
6
which comprises a ball bearing
4
on the inside end and a roller bearing
5
on the outside end (the outside with reference to the axial direction is the side furthest from the engine, and is the left side in all of the figures) in combination to support a rotating shaft
3
such that it rotates freely on the radially inside of the housing
1
. There are seal rings
7
,
7
located on both ends in the axial direction (left and right direction in
FIG. 4
) of this rolling-bearing unit
6
that prevent the grease filled inside the bearing unit from leaking out, as well as, prevent foreign matter such as dirt or steam on the outside from getting inside the unit. Moreover, a pulley
8
is fastened to a section on the outside end of the aforementioned rotating shaft
3
that protrudes from the opening on the outside end of the housing
1
.
When installed in the engine, a belt (not shown in the figure) is placed around this pulley
8
, and it rotates and drives the aforementioned rotating shaft
3
from the crankshaft of the engine. On the other hand, an impeller
9
is fastened to a section on the inside end of the rotating shaft
3
that protrudes from the surface on the inside end of the installation flange
2
. When this installation flange
2
is fastened to the cylinder block of the engine, the aforementioned impeller
9
goes inside the water jacket that is formed within this cylinder block. As the rotating shaft
3
rotates, the coolant water inside the water jacket is circulated to and from a radiator (not shown in the figure) or that like.
Furthermore, there is a mechanical seal
10
located between the outer peripheral surface of the rotating shaft
3
and the inner peripheral surface of the housing
1
. When the engine is operating, this mechanical seal
10
allows rotation of the rotating shaft
3
while at the same time prevents steam or coolant water that is flowing inside the water jacket, from leaking out. However, with the aforementioned mechanical seal
10
, obtaining a perfect seal is difficult, and when if friction heat is generated on the seal surface of this mechanical seal
10
, the coolant water, which contains chemical matter such as an anti-freeze agent or anti-rust agent, evaporates and becomes steam and leaks out toward the rolling-bearing unit
6
, while at the same time, the coolant water in which the aforementioned chemical matter is condensed due to evaporation of the coolant water and also leaks out to the rolling-bearing unit
6
. Therefore, a singer
11
is located in the middle of the rotating shaft
3
between the mechanical seal
10
and the inside seal ring
7
, and a supply-discharge hole (not shown in the figure) is formed in the middle of the housing
1
in the section that faces the outer peripheral edge of the singer
11
, which allows the steam or hot water that leaked out from the mechanical seal
10
to freely be discharged outside the housing
10
. In other words, the aforementioned supply-discharge hole is provided for communication between the outside and a space which is located between the mechanical seal
10
and the inside seal ring
7
in the axial direction to act as a steam chamber, so that the steam and hot water in this space are discharged to the outside.
In the first example of prior art construction shown in
FIG. 4
, the inner peripheral edge of a pair of seal lips
12
,
12
of the inside seal ring
7
comes in sliding contact all the way around the outer peripheral surface in the middle of the rotating shaft
3
. The inside seal ring
7
and aforementioned singer
11
are not associated with and are independent of each other.
With respect to this, as shown in
FIG. 5
, Japanese Patent Publication No. Toku Kai Hei 11-153096 discloses a construction for improving the seal performance by locating the seal ring
7
a
and singer
11
a
such that they are associated with each other. In the case of this construction, two of the three lips
12
a
,
12
b
and
12
c
of the seal ring
7
a
, specifically the seal lips
12
a
and
12
b
come in sliding contact all the way around the outer peripheral surface of the rotating shaft
3
a
. On the other hand, the edge of the remaining seal lip
12
c
comes in sliding contact all the way around the outside surface of the singer
11
a
. With this kind of construction, the seal performance is improved over the first example of prior art construction shown in
FIG. 4
, and it is possible to more effectively prevent foreign matter such as steam or hot water from getting inside the rolling-bearing unit that supports the rotating shaft
3
a.
In the case of a second example of prior art construction shown in
FIG. 5
, the seal is better than the first example of prior art construction shown in FIG.
4
. However, in order to be able to effectively prevent foreign matter from getting into the bearing unit over a long period of time, further improvement is desired. In other words, in the case of the construction disclosed in Japanese Patent Publication No. Toku Kai Hei 11-153096 as shown in
FIG. 5
, only the construction in which the edge of one of the three seal lips
12
a
,
12
b
and
12
c
of the seal ring
7
a
, that is of the seal lips
12
c
, comes in sliding contact with the outside surface of the singer
11
a
is mentioned, however detailed specifications are not given.
With respect to this point, in order to be able to effectively prevent foreign matter from getting into the bearing unit over a long period of time, it is necessary to satisfy the following conditions (1) and (2).
(1) The tip edge of the seal lip
12
c
must come in sliding contact all the way with the outside surface of the singer
11
a
with sufficient pressure and with no gaps.
(2) Wear of the tip edge of the seal lip
12
c
due to rubbing with the outside surface of the singer
11
a
must be kept to a minimum.
In the case of satisfying only condition (1) above, it is possible to increase the amount of elastic deformation of the seal lip
12
c
and increase the force to push the tip edge of the seal lip
12
c
against the outside surface of the singer
11
a
. On the other hand, in the case of satisfying only condition (2) above, it is possible to reduce the amount of elastic deformation of the seal lip
12
c
and decrease the force to push the tip edge of the seal lip
12
c
against the outside surface of the singer
11
a.
Since the condition (1) above for securing the seal performance is counter to the condition (2) above for securing durability in this way, actual construction for effectively preventing foreign matter from getting inside the bearing unit over a long period of time is very important.
DISCLOSURE OF THE INVENTION
It is an objective of this invention to provide a seal apparatus for a water pump, rotation-support apparatus for a water pump and a water pump, taking the aforementioned problems into consideration.
Of the seal apparatus for a water pump, rotation-support apparatus for a water pump and water pump of this invention, the seal apparatus for a water pump as disclosed in the claims comprises a seal ring provided to block the space between the inner peripheral surface of a non-rota
Crowell & Moring LLP
NSK Ltd.
Verdier Christopher
LandOfFree
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