U.S. patent application number 13/469202 was filed with the patent office on 2012-12-20 for water pump.
This patent application is currently assigned to Hitachi Automotive Systems, Ltd.. Invention is credited to Shingo MURAKAMI, Hideaki NAKAMURA, Masahiko WATANABE.
Application Number | 20120321489 13/469202 |
Document ID | / |
Family ID | 47228643 |
Filed Date | 2012-12-20 |
United States Patent
Application |
20120321489 |
Kind Code |
A1 |
MURAKAMI; Shingo ; et
al. |
December 20, 2012 |
Water Pump
Abstract
A water pump is constructed to have a rotating member that is
adapted to be rotated by an external driving source, a housing that
forms a part of a pump chamber from which a cooling water is led to
an internal combustion chamber for cooling the engine upon rotation
of the rotating member, a mechanical seal unit that is installed
between the housing and the rotating member to seal the pump
chamber and a bearing that is operatively disposed between the
rotating member and the housing at a position other than the pump
chamber, in which an annular slinger is arranged at an axial end of
the bearing and fixed to a fixed portion, the annular slinger
having a given portion that slidably contacts to the rotating
member.
Inventors: |
MURAKAMI; Shingo;
(Atsugi-shi, JP) ; WATANABE; Masahiko;
(Yokohama-shi, JP) ; NAKAMURA; Hideaki;
(Yokohama-shi, JP) |
Assignee: |
Hitachi Automotive Systems,
Ltd.
Hitachinaka-shi
JP
|
Family ID: |
47228643 |
Appl. No.: |
13/469202 |
Filed: |
May 11, 2012 |
Current U.S.
Class: |
417/364 |
Current CPC
Class: |
F01P 5/12 20130101; F16C
33/7896 20130101; F16C 2360/44 20130101; F16C 33/7886 20130101;
F04D 29/106 20130101; F16C 19/06 20130101 |
Class at
Publication: |
417/364 |
International
Class: |
F04D 1/00 20060101
F04D001/00; F04D 13/02 20060101 F04D013/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 14, 2011 |
JP |
2011-132180 |
Claims
1. A water pump comprising: a rotating unit including a pulley, a
drive shaft and an impeller which rotate as a single unit; a
housing covering the drive shaft and having a pump chamber for
receiving therein the impeller; a mechanical seal unit installed
between the housing and the drive shaft to seal the pump chamber; a
bearing including an outer race fixed to one of the rotating unit
and the housing, an inner race fixed to the other one of the
rotating unit and the housing and a plurality of rotating bodies
operatively disposed between the outer and inner races; an annular
seal member arranged at an axial end of the bearing and having a
peripheral portion that is fixed to one of the outer and inner
races and another peripheral portion that slidably contacts with
the other one of the outer and inner races; and an annular slinger
fixed to the housing in a manner to face the annular seal member,
the annular slinger having a given portion that slidably contacts
with a given portion of the rotating unit.
2. A water pump as claimed in claim 1, in which the outer race of
the bearing is tightly disposed in a first cylindrical portion
provided by the pulley and the inner race of the bearing is tightly
disposed on an outer cylindrical surface of the housing.
3. A water pump as claimed in claim 2, in which the pulley has a
second cylindrical portion that surrounds the first cylindrical
portion.
4. A water pump as claimed in claim 3, in which the first and
second cylindrical portions are connected through an annular wall
portion that faces toward the impeller and in which the first
cylindrical portion is connected to one end of the drive shaft that
is opposite to the other end to which the impeller is
connected.
5. A water pump as claimed in claim 4, in which another annular
wall portion that extends from the first cylindrical portion toward
the one end of the drive shaft is formed, at an annular zone
thereof facing one end of the inner race, with a plurality of
openings and in which the inner race of the bearing is press-fitted
onto the outer cylindrical surface of the housing.
6. A water pump as claimed in claim 5, in which the pulley and the
drive shaft are separate members.
7. A water pump as claimed in claim 1, in which the given portion
of the annular slinger is arranged to slidably contact with one of
the outer race of the bearing and the pulley.
8. A water pump as claimed in claim 1, in which the given portion
of the annular slinger is arranged to slidably contact with one of
the outer race of the bearing and the pulley through a rubber
member.
9. A water pump as claimed in claim 8, in which the rubber member
is integral with a rubber cover member that intimately covers the
annular slinger.
10. A water pump as claimed in claim 1, in which the annular
slinger is arranged to slidably contact with the annular seal
member.
11. A water pump as claimed in claim 1, in which the given portion
of the annular slinger is provided with a solid lubricant film of
which outer surface slidably contacts with either one of the outer
race of the bearing and the pulley.
12. A water pump as claimed in claim 11, in which the annular
slinger is made of a resilient member.
13. A water pump as claimed in claim 1, in which the annular
slinger is tightly put between an axial end of the bearing and a
stepped portion provided by the housing, and in which the stepped
portion of the housing is provided with an annular groove to which
an inner peripheral portion of the annular slinger is exposed.
14. A water pump as claimed in claim 1, in which grease is applied
to the given portion of the annular slinger.
15. A water pump as claimed in claim 1, in which an outer
peripheral portion of the annular seal member is fixed to the outer
race of the bearing that is fixed to the rotating unit and in which
an inner peripheral portion of the annular seal member has seal
lips that slidably contact to the inner race of the bearing that is
fixed to the housing.
16. A water pump as claimed in claim 1, in which the annular
slinger is made of a metal having a high thermal conductivity.
17. A water pump as claimed in claim 16, in which the annular
slinger is made of an aluminum alloy.
18. A water pump as claimed in claim 1, in which the bearing is a
ball bearing of single ball-row type.
19. A water pump comprising: a rotating unit including a pulley, a
drive shaft and an impeller which rotate as a single unit; a
housing covering the drive shaft and having a pump chamber for
receiving therein the impeller; a mechanical seal unit installed
between the housing and the drive shaft to seal the pump chamber; a
bearing including an outer race fixed to one of the rotating unit
and the housing, an inner race fixed to the other one of the
rotating unit and the housing and a plurality of rotating bodies
operatively disposed between the outer and inner races; and an
annular slinger arranged in a passage extending between the bearing
and the mechanical seal unit, the annular slinger being fixed to
the housing and having a given portion that slidably contacts to a
rotating member fixed to the rotating unit, the rotating member
being either one of the outer and inner races of the bearing.
20. A water pump comprising: a rotating member adapted to be
rotated by an external driving source; a housing that forms at
least a part of a pump chamber from which a cooling water is led to
an internal combustion chamber for cooling the engine upon rotation
of the rotating member; a mechanical seal unit installed between
the housing and the rotating member to seal the pump chamber; a
bearing operatively disposed between the rotating member and the
housing at a position other than the pump chamber; and an annular
slinger arranged at an axial end of the bearing and fixed to a
fixed portion, the annular slinger having a given portion that
slidably contacts to the rotating member.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates in general to water pumps for
pumping a cooling water that circulates in an engine cooling system
of a motor vehicle, and more particularly to the water pumps of a
type that provides a bearing of a rotating member with a watertight
construction.
[0003] 2. Description of the related Art
[0004] Japanese Laid-open Patent Application (Tokkai) 2010-169143
shows a water pump that has a watertight construction for a bearing
of a rotating member.
[0005] In the water pump shown in the publication, there is
disclosed a watertight construction between a cylindrical pump
housing and a drive shaft that is concentrically and rotatably
disposed in the pump housing. Between the pump housing and the
drive shaft, there is disposed a ball bearing of a type that has
two rows of balls for smoothing rotation of the drive shaft.
[0006] The watertight construction comprises a seal member that is
fixed to the pump housing and has first and second lip portions
slidably contacting with a flat portion formed on the drive shaft,
and an annular slinger that is fixed to the drive shaft and has a
peripheral portion to which a third lip (or axial lip) of the seal
member slidably contacts. Due to the first and second lips that
slidably contact to the flat portion of the drive shaft, there are
defined two sealing portions by which water penetration into the
ball bearing is restrained.
SUMMARY OF THE INVENTION
[0007] Although the watertight construction disclosed by the
above-mentioned publication exhibits a watertight function to a
certain extent due to provision of the two sealing portions, the
sliding contact between the third lip and the annular slinger
causes formation of an annular space in which water is collected,
which however promotes the undesired penetration of water into the
ball bearing from the annular space through the two sealing
portions.
[0008] It is therefore an object of the present invention to
provide a water pump which is free of the above-mentioned
drawback.
[0009] According to the present invention, there is provided an
improved watertight construction for a ball bearing installed in a
water pump, that exhibits a satisfied watertight function by
providing means by which water staying in the annular space is
easily discharged therefrom.
[0010] In accordance with a first aspect of the present invention,
there is provided a water pump which comprises a rotating unit
including a pulley, a drive shaft and an impeller which rotate as a
single unit; a housing covering the drive shaft and having a pump
chamber for receiving therein the impeller; a mechanical seal unit
installed between the housing and the drive shaft to seal the pump
chamber; a bearing including an outer race fixed to one of the
rotating unit and the housing, an inner race fixed to the other one
of the rotating unit and the housing and a plurality of rotating
bodies operatively disposed between the outer and inner races; an
annular seal member arranged at an axial end of the bearing and
having a peripheral portion that is fixed to one of the outer and
inner races and another peripheral portion that slidably contacts
with the other one of the outer and inner races; and an annular
slinger fixed to the housing in a manner to face the annular seal
member, the annular slinger having a given portion that slidably
contacts with a given portion of the rotating unit.
[0011] In accordance with a second aspect of the present invention,
there is provided a water pump which comprises a rotating unit
including a pulley, a drive shaft and an impeller which rotate as a
single unit; a housing covering the drive shaft and having a pump
chamber for receiving therein the impeller; a mechanical seal unit
installed between the housing and the drive shaft to seal the pump
chamber; a bearing including an outer race fixed to one of the
rotating unit and the housing, an inner race fixed to the other one
of the rotating unit and the housing and a plurality of rotating
bodies operatively disposed between the outer and inner races; and
an annular slinger arranged in a passage extending between the
bearing and the mechanical seal unit, the annular slinger being
fixed to the housing and having a given portion that slidably
contacts to a rotating member fixed to the rotating unit, the
rotating member being either one of the outer and inner races of
the bearing.
[0012] In accordance with third aspect of the present invention,
there is provided a water pump which comprises a rotating member
adapted to be rotated by an external driving source; a housing that
forms at least a part of a pump chamber from which a cooling water
is led to an internal combustion chamber for cooling the engine
upon rotation of the rotating member; a mechanical seal unit
installed between the housing and the rotating member to seal the
pump chamber; a bearing operatively disposed between the rotating
member and the housing at a position other than the pump chamber;
and an annular slinger arranged at an axial end of the bearing and
fixed to a fixed portion, the annular slinger having a given
portion that slidably contacts to the rotating member.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Other objects and advantages of the present invention will
become apparent from the following description when taken in
conjunction of the accompanying drawings, in which:
[0014] FIG. 1 is an exploded view of a water pump of a first
embodiment of the present invention;
[0015] FIG. 2 is a front view of the water pump of the first
embodiment of the present invention;
[0016] FIG. 3 is a sectional view taken along the line A-A of FIG.
2;
[0017] FIG. 4 is an enlarged sectional view of an essential portion
of the water pump of the first embodiment;
[0018] FIG. 5 is a sectional view of a slinger that is usable as a
part of a watertight construction employed in the water pump of the
first embodiment;
[0019] FIG. 6 is a view similar to FIG. 5, but showing another
slinger that is also usable as a part of the watertight
construction employed in the water pump of the first
embodiment;
[0020] FIG. 7 is a view similar to FIG. 4, but showing an essential
portion of a water pump of a second embodiment of the present
invention;
[0021] FIG. 8 is a view similar to FIG. 4, but showing an essential
portion of a water pump of a third embodiment of the present
invention; and
[0022] FIG. 9 is a view similar to FIG. 4, but showing an essential
portion of a water pump of a fourth embodiment of the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0023] In the following, water pumps of various embodiments of the
present invention will be described in detail with reference to the
accompanying drawings.
[0024] The water pumps to which the following explanation is
directed are of a type that is used for pumping a cooling water
that circulates in an engine cooling system of a motor vehicle
powered by an internal combustion engine. More specifically, the
water pump is of a type that is mounted on a side wall of an engine
block and powered by a crankshaft of the engine for circulating
cooling water through a water jacket formed in the engine
block.
[0025] In the following description, various directional terms,
such as right, left, upper, lower, rightward and the like are used
for ease of explanation. It is however to be noted that such terms
are to be understood with respect to only a drawing or drawings on
which a corresponding part or portion is shown.
[0026] Referring to FIGS. 1, 2, 3 and 4, particularly FIGS. 1 and
3, there is shown a water pump 1A of a first embodiment of the
present invention.
[0027] As is seen from FIG. 1, water pump 1A comprises a pump
housing 2 that has at its left side a cylindrical portion 11 and at
its right side a flange portion 2a integrated with a right end of
the cylindrical portion 11. Pump housing 2 is a cast product of
aluminum alloy and fixed to a side surface of an engine block (not
shown) through flange portion 2a thereby to form a pump chamber P
(or volute chamber, see FIG. 3) between pump housing 2 and the
engine block.
[0028] As is best seen from FIG. 3, a drive shaft 3 is rotatably
and coaxially installed in pump housing 2 through an
after-mentioned mechanical seal unit 10. Drive shaft 3 has a left
end (in FIG. 3) that is projected outward or leftward from pump
housing 2. To the projected left end of the drive shaft 3, there is
fixed a central hollow portion 4c of a pulley 4. Although not shown
in the drawing, a drive belt is put on pulley 4 to transmit a
turning force (or torque) to drive shaft 3 from a crankshaft of the
engine.
[0029] As is seen from FIGS. 1 and 3, a conical cover 5 is fixed to
a left portion of pulley 4 in a manner to cover the substantially
entire left surface of pulley 4, as shown.
[0030] As is best seen from FIG. 3, between pulley 4 and a smaller
diameter end portion 11c of pump housing 2, there is concentrically
disposed a ball bearing 6 to allow a smoothed rotation of pulley 4
around smaller diameter end portion 11e of pump housing 2. Ball
bearing 6 comprises an inner race 16 fixed to smaller diameter end
portion 11c, an outer race 17 fixed to pulley 4 and a plurality of
balls 18 rotatably disposed between the inner and outer races 16
and 17.
[0031] As is seen from FIGS. 3 and 4, between pulley 4 and smaller
diameter end portion 11c of pump housing 2, there is concentrically
arranged an annular slinger 7 of which inner peripheral portion is
fixed to the pump housing 2. As is best seen from FIG. 4, annular
slinger 7 is oriented to face a right end of ball bearing 6. Due to
provision of annular slinger 7, water penetration into ball bearing
6 is restrained for the reasons that will be described
hereinafter.
[0032] Referring back to FIG. 3, drive shaft 3 has a right end to
which the central hollow portion 8c of an impeller 8 is fixed.
Thus, under rotation of drive shaft 3, impeller 8 is rotated in
pump chamber P.
[0033] As is seen from FIG. 3, cylindrical portion 11 of pump
housing 2 comprises a larger diameter portion 11a that is formed
beside the above-mentioned flange portion 2a, an intermediate
diameter portion 11b that extends leftward from larger diameter
portion 11a through a radially extending annular portion (no
numeral) and a smaller diameter end portion 11c that extends
leftward from intermediate diameter portion 11b through a radially
extending annular portion 11d. As shown, an inner diameter of
smaller diameter end portion 11c gradually increases as a distance
from the left end of the end portion 11c increases.
[0034] Below intermediate diameter portion lib in FIG. 3, there is
defined a drain chamber 12 that communicates with an inside space
of the portion 11b through a drain passage 13. Denoted by numeral 9
is a plug for sealing drain chamber 12.
[0035] As is seen from FIG. 3, between intermediate diameter
portion 11b and drive shaft 3, there is concentrically disposed a
mechanical seal unit 10 by which water penetration or invasion
toward ball bearing 6 from pump chamber P is suppressed or at least
minimized. However, since complete stopping of the water
penetration toward ball bearing 6 is not effected by only the
mechanical seal unit 10, the following water drain construction is
provided.
[0036] That is, the water drain construction comprises the drain
passage 13 that is formed in a thicker lower portion of
intermediate diameter portion 11b to communicate the inside space
of the portion 11b with drain chamber 12. That is, drain passage 13
extends along the Y-axis of FIG. 3. Due to provision of drain
passage 13, cooling water that would penetrate into the inside
space of intermediate diameter portion 11b from pump chamber P
through the mechanical seal unit 10 is drained into drain chamber
12. Thus, water penetration toward the interior of smaller diameter
end portion 11c is suppressed or at least minimized.
[0037] In addition to the above-mentioned drain passage 13,
intermediate diameter portion 11b is formed, at a position
diametrically opposite to the position of the drain passage 13,
with a connecting opening 14 to communicate the interior of the
portion 11b with the outside of pump housing 2. That is, connecting
opening 14 extends along the Y-axis of FIG. 3. Due to provision of
connecting opening 14, water vapor produced in drain chamber 12 can
escape into the outside of pump housing 2.
[0038] Drive shaft 3 is made of a steel and rotatably disposed in
pump housing 2 with its axially opposed ends projected outward from
pump housing 2, as shown.
[0039] As is seen from FIG. 3, drive shaft 3 is formed at a portion
thereof facing the drain passage 13 and connecting opening 14 with
an annular groove 3a that has a given width. Due to provision of
annular groove 3a, penetrating water on the outer surface of drive
shaft 3 is suppressed from directly flowing toward the interior of
smaller diameter end portion 11c. That is, the penetrating water is
trapped by annular groove 3a and then led to drain chamber 12
through drain passage 13.
[0040] Pulley 4 is produced by pressing a steel plate and as is
seen from FIG. 1, pulley 4 has a cylindrical shape.
[0041] As is seen from FIG. 3, pulley 4 comprises a tubular base
portion 4a (or first tubular portion) that is shaped to surround
the smaller diameter end portion 11c of pump housing 2, a belt
putting rim portion 4b (or second tubular portion) that is shaped
to surround tubular base portion 4a and integrally connected to
tubular base portion 4a through an annular wall portion 4f and the
above-mentioned central hollow portion 4c that is integrally
connected to tubular base portion 4a through an annular wall
portion 4e and fixed to the left end of drive shaft 3. As is seen
from FIG. 3, for the fixing between pulley 4 and drive shaft 3, the
left end of drive shaft 3 is press-fitted into the central hollow
portion 4c of pulley 4.
[0042] As shown in FIG. 3, tubular base portion 4a of pulley 4
comprises a cylindrical wall 4d that is intimately and tightly
disposed on outer race 17 of ball bearing 6 and the above-mentioned
annular wall portion 4e. The wall portion 4e extends radially
inward from a left end of cylindrical wall 4d to a right end of
central hollow portion 4c. For the assembly, ball bearing 6 is
press-fitted into tubular base portion 4a, and then, smaller
diameter end portion 11c of pump housing 2 is press-fitted into
ball bearing 6.
[0043] As will be understood from FIG. 3, annular wall portion 4e
of pulley 4 is formed with a plurality of openings 15 through which
the penetrating water in the interior of smaller diameter end
portion 11c of pump housing 2 is discharged to the outside of water
pump 1A. Openings 15 are arranged at evenly spaced intervals. Each
opening 15 extends along the X-axis of FIG. 3.
[0044] Each opening 15 is so positioned and arranged as to place at
least part thereof to a position where an inside end of an
after-mentioned first annular seal member 19 and the inner race 16
of ball bearing 6 contact. More specifically, each opening 15 is
arranged to substantially face the given contact portion between
the first annular seal member 19 and the inner race 16. With this
arrangement, the penetrating water or water vapor in the interior
of smaller diameter end portion 11c is smoothly discharged into the
outside through each opening 15 before arriving at the first
annular seal member 19. Due to provision of plural openings 15, the
water discharging from pump housing 2 is effectively carried out.
Furthermore, since openings 15 are arranged to axially face inner
race 16 of ball bearing 6, the openings 15 can be used as work
assist openings for the tools that are manipulated or handled to
place the ball bearing 6 onto an exact position of the smaller
diameter end portion 11c.
[0045] The above-mentioned conical cover 5 is produced by pressing
a corrosion-resistant metal plate, such as aluminum plate,
stainless plate or the like.
[0046] As is seen from FIG. 3, conical cover 5 comprises a main
cover portion 5a that covers tubular base portion 4a of pulley 4
and a central annular portion 5b that is tightly mounted on central
hollow portion 4c of pulley 4 through press-fitting. As is seen,
main cover portion 5a of conical cover 5 extends radially outwardly
from central annular portion 5b to a position near an inside part
of belt putting rim portion 4b of pulley 4. Due to provision of
conical cover 5, direct penetration or invasion of water or foreign
substances into pump housing 2 through openings 15 is
suppressed.
[0047] The above-mentioned ball bearing 6 is of a single ball-row
type with seal members. That is, ball bearing 6 is snugly disposed
between an outer cylindrical surface of smaller diameter end
portion 11c of pump housing 2 and an inner cylindrical surface of
cylindrical wall 4d of pulley 4.
[0048] As is mentioned hereinabove, ball bearing 6 comprises inner
race 16 that is press-fitted to the outer surface of smaller
diameter end portion 11c, outer race 17 that is press-fitted to the
inner surface of cylindrical wall 4d and a plurality of balls 18
that are rotatably and partially received in guide grooves (no
numerals) respectively formed in inner and outer races 16 and
17.
[0049] As is seen from FIG. 3, ball bearing 6 is equipped with
first and second annular seal members 19 and 20. These first and
second annular seal members 19 and 20 are arranged at axially
opposed ends of ball bearing 6 respectively in a manner to cover
axially opposed open ends of an annular space (no numeral) defined
by inner and outer races 16 and 17.
[0050] As will be understood from FIGS. 3 and 4, outer peripheries
of first and second annular seal members 19 and 20 are fixed to
axially opposed inside ends of outer race 17 by caulking, while, as
will be described in detail hereinafter, inner peripheries of first
and second annular seal members 19 and 20 are arranged to slide in
grooves respectively formed in axially opposed inside ends of inner
race 16. Due to provision of first annular seal member 19, water
penetration from the interior of smaller diameter end portion 11c
to the interior of ball bearing 6 is suppressed.
[0051] As is seen from FIG. 4, due to provision of second annular
seal member 20 and the above-mentioned annular slinger 7 placed
near second annular seal member 20, water penetration from the
outside to the interior of ball bearing 6 is suppressed.
[0052] Since first and second annular seal members 19 and 20 have
substantially the same construction, the following detailed
description on the construction will be directed to only second
annular seal member 20 for simplification of explanation.
[0053] As is seen from FIG. 4, second annular seal member 20
comprises an annular metal core member 20a and an annular rubber
cover member 20x that covers an outer surface of annular metal core
member 20a. The outer periphery of second annular seal member 20 is
fixed to the inner end of outer race 17 by caulking, and the inner
periphery of second annular seal member 20 is in contact with an
inclined wall of an annular cut (no numeral) formed in the inner
end of inner race 16.
[0054] That is, the inner periphery of second annular seal member
20 is shaped into a seal lip member 20b that includes first and
second seal lips 20d and 20e. As shown, first and second seal lips
20d and 20e are parts of the rubber cover 20x and slidably and
elastically pressed against the inclined wall of the annular cut of
inner race 16.
[0055] Due to provision of seal lip member 20b elastically pressed
against the inclined wall of inner race 16, there is produced a
first sealing section S1 by which penetration or invasion of
foreign substances from the outside into ball bearing 6 is
suppressed. Due to provision of the two seal lips 20d and 20e, a
so-called double sealing structure is defined by second annular
seal member 20.
[0056] Since first annular seal member 19 (see FIG. 3) has the same
structure as the above-mentioned second annular seal member 20,
penetration or invasion of foreign substances into ball bearing 6
from the inner space of smaller diameter end portion 11c of pump
housing 2 is suppressed.
[0057] As is best shown in FIG. 4, annular slinger 7 secured to
pump housing 2 is arranged to face the right end of ball bearing
16. Annular slinger 7 comprises an annular metal core member 21 and
an annular rubber cover member 22 that covers a radially outside
portion of annular metal core member 21 except a left surface that
faces second annular seal member 20. Annular metal core member 21
is made of a metal having a high thermal conductivity and suitable
resiliency. One example of such metal is aluminum alloy.
[0058] As shown, annular slinger 7 has an inner peripheral portion
21a that is fixed to an outer surface of smaller diameter end
portion 11c of pump housing 2 and an outer peripheral portion that
is provided with an annular seal lip 23. The outer peripheral
portion of annular slinger 7 is placed near an inner surface of
cylindrical wall 4d of pulley 4. In FIG. 4, the space formed
between the outer periphery of annular slinger 7 and the inner
surface of cylindrical wall 4d is denoted by C1. As shown, s
annular seal lip 23 is a part of rubber cover member 22 and
slidably and elastically pressed against a right end surface of
outer race 17.
[0059] As is seen from FIGS. 3 and 4, due to provision of annular
seal lip 23, foreign substances from the outside and cooling water
that would arrive thereto through connecting opening 14 from
mechanical seal unit 10 are suppressed from invading the interior
of ball bearing 6.
[0060] As is seen from FIG. 4, inner peripheral portion 21a of
annular slinger 7, that is tightly disposed on the outer surface of
smaller diameter end portion 11c of pump housing 2, is sandwiched
between an annular ridge 11d' formed on radially extending annular
portion 11d of pump housing 2 and the right end of inner race 16 of
ball bearing 6.
[0061] Thus, inner race 16 of ball bearing 6, annular slinger 7 and
pump housing 2 constitute a first single unit which is fixed. It is
to be noted that in FIG. 4, cylindrical wall 4d and outer race 17
constitute a second single unit that turns around the fixed first
single unit.
[0062] As is seen from FIG. 4, the outer peripheral portion of
annular slinger 7 is slightly depressed rightward and thus there is
defined a given space C2 between the right end of ball bearing 6
and the outer peripheral portion of annular slinger 7. The space C2
is sealed by annular seal lip 23, as shown.
[0063] As is seen from FIGS. 3 and 4, radially extending annular
portion 11d of pump housing 2 is formed with an annular groove 24
at a radially inside position of annular ridge 11d'. More
specifically, as shown, the radially inside end of annular groove
24 is mated with the cylindrical outer surface of smaller diameter
end portion 11c. With this arrangement, exact setting of the inner
periphery of annular slinger 7 onto the cylindrical outer surface
of smaller diameter end portion 11c is achieved. This is because
the inner periphery of annular slinger 7 can have an increased
flexibility in selecting the best set position due to provision of
annular groove. If such annular groove 24 is not provided, the
flexibility in selecting the best set position for the inner
periphery of annular slinger 7 would be lowered. That is, due to
provision of annular groove 24, annular slinger 7 can be exactly
and tightly disposed on smaller diameter end portion 11c of pump
housing 2 without rattle.
[0064] Annular seal lip 24 is so sized and constructed as to be
sufficiently pressed against the right end of outer race 17 even
when a certain displacement is taken place by outer race 17 under
operation of the water pump 1A. The displaced positions of outer
race 17 are shown by broken lines in FIG. 4.
[0065] Due to provision of annular seal lip 24 elastically pressed
against the right end of outer race 17, there is provided a second
sealing section S2 by which invasion of foreign substances from the
outside into the space C2 and thus into ball bearing 6 is
suppressed.
[0066] As is seen from FIGS. 1, 2 and 3, particularly FIG. 2, the
above-mentioned impeller 8 is fixed at its central hollow portion
8c to the projected right end of drive shaft 3. Like pulley 4,
impeller 8 is produced by pressing a steel plate and has an
integrated structure.
[0067] As is well shown in FIGS. 2 and 3, impeller 8 comprises an
annular base portion 8a, a plurality of vanes 8b pressed out of a
peripheral portion of annular base portion 8a and the
above-mentioned central hollow portion 8c.
[0068] As is described in detail hereinabove, in water pump 1A
according to the present invention, there are arranged two, viz.,
first and second sealing sections S1 and S2 in series in a passage
that extends from the outside (or water drain chamber 12) to the
interior of ball bearing 6. Furthermore, in water pump 1A, there is
further arranged a third sealing section that is constructed by
first annular seal member 19 (see FIG. 3) and arranged in a passage
that extends from the outside to the interior of ball bearing 6
through openings 15 of pulley 4. Accordingly, invasion or
penetration of foreign substances and water into the interior of
ball bearing 6 is quite effectively suppressed.
[0069] In the following, conspicuous effects of water pump 1A of
the first embodiment of the present invention will be described
with the aid of FIGS. 3 and 4.
[0070] Due to the nature of water pump 1A having the
above-mentioned construction, there is inevitably formed a first
given space SP1 (see FIG. 4) defined by pulley 4, ball bearing 6
and is annular slinger 7. Thus, under operation of water pump 1A,
first given space SP1 tends to collect therein leaked cooling water
from connecting opening 14 (see FIG. 3) and foreign substances from
the outside.
[0071] However, for the following reasons, such tendency is
suppressed or at least minimized. That is, as is seen from FIG. 3,
upon starting of the associated engine, pulley 4 is turned around
the fixed smaller diameter end portion 11c of pump housing 2 and
thus, as is seen from FIG. 4, outer race 17 of ball bearing 6,
which is secured to pulley 4, turns around the axis of drive shaft
3 keeping a contact of the right end surface thereof with annular
seal lip 23 of slinger 7. Due to frictional heat produced by the
sliding contact between the right end surface of outer race 17 and
annular seal lip 23, water collected in first given space SP1 is
evaporated and thus removed therefrom. This reduces the possibility
of leakage of water through second sealing section S2. If the
leading end of annular seal lip 23 is arranged to contact a
radially outer side of the right end surface of outer race 17 as
shown in FIG. 4, the frictional heat is much effectively produced
due to an increased speed with which the leading end of annular
seal lip 23 contacts the right end surface of outer race 17. Of
course, in this case, water evaporation is much effectively
made.
[0072] In addition to the above, heat transmitted to annular
slinger 7 from pump housing 2 promotes the above-mentioned water
evaporation. That is, cooling water pumped up by water pump 1A is
led to the engine block for cooling the engine, and thus, the
cooling water is heated by the engine block before rerunning to
water pump 1A. This means that under operation of water pump 1A,
pump housing 2 that defines pump chamber P therein is heated to a
certain level and thus annular slinger 7 connected to pump housing
2 is also heated by the heat transfer from heated pump housing 2.
Heating of annular slinger 7 induces heating of annular seal lip
23, which promotes the water is evaporation at first given space
SP1.
[0073] Even if the water (viz., cooling water or foreign
substances) passes through the second sealing section S2 and enters
into a second given space SP2 (see FIG. 4) that is defined by
annular slinger 7, annular seal lip 23, the right end surface of
outer roller 17 and second annular seal member 20, the water in
second given space SP2 is evaporated by the heat transmitted to
annular slinger 7 and inner race 16 of ball bearing 6 from pump
housing 2. That is, even if water leaks into second given space SP2
from first given space SP1, the possibility of inversion or
penetration of water into the interior of ball bearing 6 is quite
small.
[0074] Because annular slinger 7 is of a fixed member, the slinger
7 is not subjected to "cooling by wind" that would be induced if
annular slinger 7 rotates, and thus, the heat accumulated in
annular slinger 7 is not lost fast. That is, in the first
embodiment, the heat transmitted to annular slinger 7 is
effectively used for evaporating water.
[0075] As is described hereinabove, in water pump 1A of the first
embodiment of the present invention, due to provision of annular
seal lip 23, invasion and penetration of foreign substances and
water from the outside and connecting passage 14 toward second
given space SP2 facing second annular seal member 20 are suppressed
or at least minimized. Furthermore, by the frictional heat produced
under operation of water pump 1A, the water staying near second
sealing section S2 is effectively evaporated. Thus, undesired
invasion or penetration of such foreign substances and water into
the interior of ball bearing 6 is suppressed or at least
minimized.
[0076] Even if water happens to leak into second given space SP2
through second sealing section S2, the heat produced under
operation of water pump 1A functions to evaporate the water and
thus suppresses or at least minimizes the possibility of invasion
or penetration of water into the interior of ball bearing 6.
[0077] Because of the above-mentioned effective watertight
construction for ball bearing 6, there is no need of using a high
precision ball bearing, such as the ball bearing having two rows of
balls between inner and outer races. Thus, production cost can be
reduced in the water pump of the invention.
[0078] Referring to FIGS. 5 and 6, there are shown modifications of
annular slinger 7, which are usable in water pump 1A of the first
embodiment.
[0079] In the modification of FIG. 5, only a peripheral portion of
annular metal core member 21 is covered with the rubber cover
member 22, as shown. For a tight mounting of rubber cover member 22
onto the metal core member 21, the peripheral portion of the metal
core member 21 is formed with a plurality of openings 21b through
which material of the rubber cover member 22 runs.
[0080] In the modification of FIG. 6, an entire construction of
annular metal core member 21 is covered with the rubber cover
member 22, as shown. In this modification, the annular metal core
member 21 is protected from corrosion.
[0081] Referring to FIG. 7, there is shown an essential portion of
a water pump 1B of a second embodiment of the present
invention.
[0082] As shown, in this second embodiment, the annular seal lip 23
of annular slinger 7 extends radially outward to slidably contact
to an inner surface of a junction portion 4x (see FIG. 3) between
tubular base portion 4a and annular wall portion 4f of pulley
4.
[0083] In this second embodiment 1B, substantially the same effects
as those of the above-mentioned first embodiment 1A are obtained
due to similar construction therebetween. However, in this second
embodiment 1B, the frictional heat produced by the sliding contact
between the junction portion 4x of pulley 4 and annular seal lip 23
is higher than that produced in the first embodiment 1A since the
junction portion 4x provides the annular seal lip 23 with a much
longer running way per each turning of pulley 4. This means that
the water staying at and near second sealing section S2 is much
effectively evaporated.
[0084] Furthermore, in water pump 1B of this second embodiment,
there is no space that corresponds to the first given space SP1 of
the first embodiment 1A. Thus, the possibility of leakage of water
through second sealing section S2 is lowered.
[0085] Referring to FIG. 8, there is shown an essential portion of
a water pump 1C of a third embodiment of the present invention.
[0086] As shown, in this third embodiment, the annular slinger 7
has no rubber cover member disposed thereon, and annular rubber
cover member 20x of second annular seal member 20 is formed with an
annular seal lip 24 that extends radially outward to slidably
contact to an inner surface 7a of the naked annular slinger 7.
[0087] Because of the naked structure of annular slinger 7, the
heat transmitted thereto from pump housing 2 is much effectively
used for producing the frictional heat by the sliding contact of
annular seal lip 24 with annular slinger 7. Thus, water staying at
and near second sealing section S2 is much effectively
evaporated.
[0088] Referring to FIG. 9, there is shown an essential portion of
a water pump 1D of a fourth embodiment of the present
invention.
[0089] As shown, in this fourth embodiment, the annular slinger 7
has no rubber cover member disposed thereon and an annular dry film
coat (or annular solid lubricant film) 25 is formed on a peripheral
part of the inner surface 7a of the naked annular slinger 7. As
shown, a major surface of annular dry film coat 25 is in contact
with the right end surface of outer race 17 of ball bearing 6. Due
to the resiliency possessed by naked annular slinger 7, the major
surface of annular dry film coat 25 is pressed against the right
end surface of the outer race 17.
[0090] Due to usage of annular dry film coat 25 that is pressed
against the right end surface of outer race 17 of ball bearing 6,
second sealing section S2 can exhibit an excellent sealing function
against water and foreign substances.
[0091] If desired, following modifications may be applied to the
water pumps of the above-mentioned embodiments.
[0092] That is, if desired, grease may be applied to the top of
annular seal lip 23 or 24 for promoting the water stopping function
of the seal lip and increasing the durability of the seal lip
against the friction in case of water pumps 1A, 1B and 1C of the
first, second and third embodiments.
[0093] Furthermore, if desired, besides the above-mentioned
water/foreign substances stopping structure including annular
slinger 7 and annular seal lip 23 or 24 or annular dry film coat
25, a structure similar to the water/foreign substances stopping
structure may be applied to a left side of ball bearing 6 (see FIG.
3).
[0094] Furthermore, if desired, another water stopping structure
may be employed in water pumps 1A, 1B, 1C and 1D. That is, the
water stopping structure comprises an annular seal lip (not shown)
that is mounted on conical cover 5 (see FIG. 3) and has a leading
end pressed against an inner surface of belt putting rim portion 4b
of pulley 4 or an outer surface of cylindrical wall 4d of pulley.
With such water stopping structure, a space S3 defined between a
periphery of conical cover 5 and the inner surface of belt putting
rim portion 4b is substantially closed, and thus, invasion of water
into ball bearing 6 through openings 15 is suppressed or at least
minimized.
[0095] The entire contents of Japanese Patent Application
2011-132180 filed Jun. 14, 2011 are incorporated herein by
reference.
[0096] Although the invention has been described above with
reference to embodiments of the invention, the invention is not
limited to such embodiments as described above. Various
modifications and variations of such embodiments may be carried out
by those skilled in the art, in light of the above description.
* * * * *