Information
-
Patent Grant
-
6213063
-
Patent Number
6,213,063
-
Date Filed
Tuesday, September 14, 199924 years ago
-
Date Issued
Tuesday, April 10, 200123 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Wolfe; Willis R.
- Harris; Katrina B.
Agents
- Birch, Stewart, Kolasch & Birch, LLP
-
CPC
-
US Classifications
Field of Search
US
- 123 4144
- 123 4146
- 123 4147
- 029 88802
- 029 888025
- 417 42314
- 464 183
- 415 2161
- 415 111
- 415 112
- 415 1221
-
International Classifications
-
Abstract
A water pump includes a pump body and a pump cover. An impeller is housed in a pump chamber defined by the pump body and pump cover. The impeller is attached to one end of a hollow pump shaft. The pump shaft is engaged with a driving section at its other end. An intermediate part of the pump shaft is supported by a shaft support section, in the form of a cylindrical section, of the pump body. The shaft support section is longer than a diameter of the pump shaft. The shaft support section is lubricated via an oil groove. One end of the shaft support section is brought into contact with a flange of the pump shaft via a washer. The flange is integrally formed on the pump shaft by a beading process.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a water pump for a water-cooled engine.
2. Description of Related Art
Japanese Utility Model Publication No. Hei 6-31197 discloses a structure of a water pump for a water-cooled engine of a motorcycle. In the water pump, an impeller is attached to one end of a hollow pump shaft, and a pump gear is attached to the other end of the pump shaft. The pump gear rotates in response to rotation of a crankshaft. The pump shaft is supported by a crankcase of the crankshaft.
The pump gear receives a thrust load from a pin. The pin has its opposite ends supported in the crankcase via the pump gear and is orthogonal to the crankcase. The pump gear is surface-supported by the crankcase.
In order to receive the thrust load by the pin, as described above, a drilling process and a force-fitting process are required in order to install the pin. Therefore, the number of components, including the pin itself, is increased. Further, the manufacturing and repair process is difficult. In order to support the pump shaft at the opposite ends thereof, the pump shaft should be centered very precisely. Therefore, the pump shaft is preferably supported at one end thereof
SUMMARY OF THE INVENTION
It is an object of the present invention to overcome one or more of the drawbacks associated with the background art.
It is a further object of the present invention to provide a water pump including a water pump shaft for rotatably supporting a water pump impeller, wherein the water pump shaft is directly and rotatably attached to a water pump body via a shaft support section.
It is a further object of the present invention to provide a water pump including a water pump shaft having an engaging portion formed at one end, opposite to an end where the impeller is supported.
It is a further object of the present invention to provide a method of forming a water pump shaft including a flange.
These and other objects are accomplished by providing a water pump for an engine comprising: a water pump body having an approximately cylindrical support section of a first diameter and a first length, wherein said first length is longer than said first diameter; a water pump shaft having a first end, a second end, and a second diameter, said second diameter being approximately equal to said first diameter, said water pump shaft lying within said cylindrical support section to be directly and rotatably attached to said water pump body; a water pump impeller included proximate said first end; and an engaging portion included proximate said second end for causing said water pump shaft and said water pump impeller to rotate relative to said water pump body.
Further, these and other objects are accomplished by providing an engine comprising: a crank case; a crank shaft rotatably mounted in said crank case; a driven member interacting with said crank shaft to rotate in response to rotation of said crankshaft; a first engaging member connected to said driven member to rotate therewith; a water pump body attached to said engine; a water pump shaft having a first end and a second end, said water pump shaft being directly and rotatably attached to said water pump body; a water pump impeller included proximate said first end; and a second engaging member included proximate said second end, said second engaging member being engaged by said first engaging member to cause said water pump shaft and said water pump impeller to rotate in response to rotation of said first engaging member.
Moreover, these and other objects are accomplished by providing a method of forming a water pump shaft of a water pump comprising the steps of: providing a die with a cylindrical opening of a first diameter formed therein; a punch having a circular groove formed in an end thereof with a protruding cylindrical portion inside the circular groove, the cylindrical protruding portion having a second diameter; and a hollow shaft with a third outer diameter approximately equal to the first diameter and a fourth inner diameter approximately equal to the second diameter; inserting one end of the hollow shaft into the circular opening of the die; inserting the cylindrical protruding portion into the hollow shaft until the hollow shaft seats into the circular groove; moving the punch toward the die; inserting the cylindrical protruding portion into the circular opening; and bending the hollow shaft in a radial direction at a point where the hollow shaft enters the die.
Other objects and further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limitative of the present invention, and wherein:
FIG. 1
is a cross sectional view of a water pump, in accordance with the present invention;
FIG. 2
is a partial cross sectional view of an engine in combination with the water pump of
FIG. 1
;
FIG.
3
(
a
) illustrates a first step in forming a water pump shaft of the water pump of
FIG. 1
;
FIG.
3
(
b
) illustrates a second step in forming the water pump shaft;
FIG.
3
(
c
) illustrates a third step in forming the water pump shaft;
FIG.
3
(
d
) illustrates a fourth step in forming the water pump shaft; and
FIG.
3
(
e
) illustrates a fifth step in forming the water pump shaft.
DESCRIPTION OF PREFERRED EMBODIMENTS
An engine structure will be outlined with reference to FIG.
2
. The engine is a water-cooled four-cycle DOHC (double overhead camshaft) engine. The engine includes a crankcase
1
, a cylinder
2
, a cylinder head
3
, and a cylinder head cover
4
which is a part of the cylinder head
3
. A piston
5
is slidably housed in the cylinder
2
and is coupled to a crankshaft
6
(the center thereof is shown in
FIG. 2
) in the crankcase
1
. A combustion chamber is provided between the piston
5
, cylinder
2
and cylinder head
3
.
An inlet port
7
and an exhaust port
8
are provided on the cylinder head
3
and communicate with the combustion chamber. The inlet port
7
and exhaust port
8
are opened and closed by an inlet valve
10
and an exhaust valve
11
, respectively. The inlet valve
10
end exhaust valve
11
are driven by cams on camshafts
12
and
13
, which are rotated in synchronization with the crankshaft
6
.
A water jacket
14
is provided on the cylinder
2
and the cylinder head
3
, and receives cooling water from a water pump
15
disposed in the crankcase
1
. Water heated in a cooling process is fed to a radiator (not shown) via a thermostat
16
attached on the cylinder head
3
. The water is cooled by the radiator, and is then returned to the water pump
15
.
The thermostat
16
is provided with a bypass circuit including a bypass hose
17
connected to the water pump
15
. When a water temperature is below a predetermined value, a thermostat valve is switched over to the bypass circuit, so that cooling water heated by the engine is not fed to the radiator, but is directly returned to the water pump
15
via the bypass hose
17
.
In
FIG. 2
, an inlet pipe
18
receives cooling water, supplied from the radiator via a hose
18
A. The engine also includes an oil pan
19
, a starting motor
21
, and a speed sensor
22
connected to a transmission. The speed sensor
22
is disposed on a main shaft
23
of the transmission. Further, the engine includes a countershaft
24
, and a shift drum
25
.
A detailed structure of the water pump
15
will now be described with reference to FIG.
1
. The water pump
15
includes a pump body
30
, and a pump cover
31
, both of which are united by bolts
32
. The pump body
30
is coupled to the crankcase
1
. An impeller
34
is housed in a pump chamber
33
defined between the pump body
30
and the pump cover
31
.
The impeller
34
is force-fitted to one end of a pump shaft
35
in order to be connected thereto. The pump shaft
35
is hollow, has its one end blocked by the impeller
34
, and has its intermediate part received in a shaft support section
37
of a cylindrical part
36
formed in the pump body
30
. A length of the shaft support section
37
is larger than a diameter of the pump shaft
35
. In a prefeffed embodiment, the length is approximately three times the diameter of the pump shaft
35
.
The shaft support section
37
is constituted by an inner surface of a through hole formed in the cylindrical member
36
. The shaft support section
37
is partially and axially provided with an oil supplying groove
38
. The oil supplying groove
38
is blocked by a seal
39
at one end thereof, and communicates with one end of an oil supplying opening
41
, formed on an inner surface of the crankcase
1
, via a radial opening
40
. The oil supplying opening
41
communicates with an oil collecting recess
42
having an open top. Oil circulating, or dispersing, in the crankcase
1
is collected in the oil collecting recess
42
, and is supplied to the shaft support section
37
via the oil supplying opening
41
and the radial opening
40
.
An inner end of the cylindrical member
36
housed in the crankcase
1
is brought into contact with a flange
44
of the pump shaft
35
via a washer
43
. The flange
44
is radially formed on the pump shaft
35
by a bending, or beading, process, as will be described later. The flange
44
is integral with the pump shaft
35
.
The other end of the pump shaft
35
has a joint
45
in the shape of a notch. The joint
45
is engaged by a projecting of a driving shaft
46
, so that the driving shaft
46
and the pump shaft
35
rotate together. The driving shaft
46
is connected to a pump gear
47
. The pump gear
47
is supported by the crankcase
1
separately from the water pump
15
. The pump gear
47
rotates in response to rotation of the crankshaft
6
.
A mechanical seal
48
is provided between an outer surface of the pump shaft
35
and the pump body
30
at the end of the pump shaft
35
where the impeller
34
is attached. The mechanical seal
48
is in contact with the impeller
34
via a floating seat
49
.
Now reference will be made to FIGS.
3
(
a
) through
3
(
e
) to describe a method of forming the flange on the pump shaft
35
. In FIG.
3
(
a
), one end of a straight pipe material
50
is inserted into an opening
52
of a die, or dies
51
, and is held therein. The opening
52
has an inner diameter that is substantially equal to an outer diameter of the pipe material
50
. The opening
52
has a depth that is equal to a distance between one end of the pump shaft
35
and the flange
44
.
In FIG.
3
(
b
), the other end of the pipe material
50
, projecting from the dies
51
, is fitted into a punch
53
. The punch
53
has an annular groove
54
for engagement with the projecting end of the pipe material
50
. A portion
55
of the punch
53
inside the annular groove
54
is fitted into the pipe material
50
. A portion
756
of the punch
53
outside the annular groove
54
recedes from a tip
57
of the portion
56
by a size D.
FIG.
3
(
c
) illustrates a state when the punch
53
is pressed and moved toward the dies
51
. A part of the pipe material
50
that is not covered by the dies
51
and the punch
53
bends or projects radially to form the flange
44
. Thus, the pipe shaft
35
has the flange
44
extending around its circumference. The size of the flange
44
can be set as desired by adjusting the size D.
In FIG.
3
(
d
), the punch
53
is moved backward, which enables the water pump shaft
35
to be detached from the dies
51
. Thereafter, the joint
45
is formed on one end of the pump shaft
35
, and the pump shaft
35
is thermally treated and polished together with the joint
45
. The shaft support section
37
may also be thermally treated and polished. The pump shaft
35
is now completed.
Some of the advantages of the water pump, in accordance with the present invention, will now be described. The shaft support section
37
of the cylindrical part
36
is longer than the diameter of the pump shaft
35
. This enables the pump shaft
35
to be directly and rotatably attached to the pump body
30
by the long shaft support section
37
, rather than having the pump shaft
35
connected to the crankcase
1
, as in the background art.
The joint
45
is provided at an end of the pump body
30
, which is opposite to the end where the impeller
34
is arranged. The joint
45
removeably engages with the driving shaft
46
. This structure enables the pump shaft
35
to be supported at one end thereof, and dispenses with a heavy member, such as a gear, provided on the pump shaft
35
. This makes the water pump light weight. Further, this simplifies the manufacturing and repair processes, since the water pump can be made without having to attach the gear onto the pump shaft
35
, and since a water pump failure in the impeller section of the water pump can be fixed without having to replace the pump gear
47
operating in conjunction with the crankshaft
6
.
The oil collector
42
, oil supplying opening
41
, and opening
40
collect oil dispersing in the crankcase
1
and guide the oil to the oil supplying groove
38
. Each may be in the shape of a duct. This system is effective in reliably supplying lubrication oil to the shaft support section
37
, thus prolonging the life of the water pump.
The hollow pump shaft
35
also has several advantages. The pump shaft
35
is light weight and can be easily manufactured. Further, the flange
44
is integrally formed in the center of the pump shaft
35
, so that the pump shaft
35
can receive the thrust load of the mechanical seal
48
at the flange
44
. Still further, no pins are required to attach the flange
44
, and the pump shaft
35
will not be drilled in order to attach pins. The bending process to form the flange
44
can be easily performed and provides excellent precision in positioning the flange
44
on the pump shaft
35
.
The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.
Claims
- 1. A water pump for an engine comprising:a water pump body having an approximately cylindrical support section of a first diameter and a first length, wherein said first length is longer than said first diameter; a water pump shaft having a first end, a second end, and a second diameter, said second diameter being approximately equal to said first diameter, said water pump shaft lying within said cylindrical support section to be directly and rotatably attached to said water pump body; a water pump impeller included proximate said first end; an engaging portion included proximate said second end for causing said water pump shaft and said water pump impeller to rotate relative to said water pump body; and a flange attached to an approximate center of said water pump shaft.
- 2. The water pump according to claim 1, wherein said water pump shaft is hollow.
- 3. The water pump according to claim 1, further comprising:an oil supplying groove formed along at least a portion of said first length of said cylindrical support section for supplying lubricating oil to the rotatable attachment between said water pump shaft and said water pump body.
- 4. The water pump according to claim 3, further comprising:an opening on an edge of said water pump body; and a duct formed in said water pump body communicating said opening to said oil groove to supply the lubricating oil to said oil supplying groove.
- 5. The water pump according to claim 1, further comprising:a washer disposed between said flange and said water pump body.
- 6. The water pump according to claim 1, wherein said flange is integrally formed as a part of said water pump shaft.
- 7. The water pump according to claim 6, wherein said water pump shaft is hollow and wherein said flange is integrally formed as a part of said water pump shaft by a bending process.
- 8. An engine comprising:a crank case; a crank shaft rotatably mounted in said crank case; a driven member interacting with said crank shaft to rotate in response to rotation of said crankshaft; a first engaging member connected to said driven member to rotate therewith; a water pump body attached to said engine; a water pump shaft having a first end and a second end, said water pump shaft being directly and rotatably attached to said water pump body; a water pump impeller included proximate said first end; and a second engaging member included proximate said second end, said second engaging member being engaged by said first engaging member to cause said water pump shaft and said water pump impeller to rotate in response to rotation of said first engaging member, wherein said second engaging member is a notch formed in said second end of said water pump shaft, and wherein said first engaging member is a protruding member adapted to mate within said notch.
- 9. The engine according to claim 8, wherein said driven member is a gear.
- 10. The engine according to claim 9, wherein said water pump body includes an approximately cylindrical support section of a first diameter and a first length, said first length being longer than said first diameter; said water pump shaft having a second diameter, said second diameter being approximately equal to said first diameter, said water pump shaft lying within said cylindrical support section to be directly and rotatably attached to said water pump body.
- 11. The engine according to claim 10, further comprising:an oil supplying groove formed along at least a portion of said first length of said cylindrical support section for supplying lubricating oil to the rotatable attachment between said water pump shaft and said water pump body.
- 12. The engine according to claim 11, further comprising:an opening on an edge of said water pump body; a duct formed in said water pump body communicating said opening to said oil supplying groove to supply the lubricating oil to said oil supplying groove; and an oil supplying reservoir within said crank case communicating with said opening.
- 13. The engine according to claim 8, wherein said water pump shaft is hollow.
- 14. A method of forming a water pump shaft of a water pump comprising the steps of:providing a die with a cylindrical opening of a first diameter formed therein; a punch having a circular groove formed in an end thereof with a protruding cylindrical portion inside the circular groove, the cylindrical protruding portion having a second diameter; and a hollow shaft with a third outer diameter approximately equal to the first diameter and a fourth inner diameter approximately equal to the second diameter; inserting one end of the hollow shaft into the circular opening of the die; inserting the cylindrical protruding portion into the hollow shaft until the hollow shaft seats into the circular groove; moving the punch toward the die; inserting the cylindrical protruding portion into the circular opening; and bending the hollow shaft in a radial direction at a point where the hollow shaft enters the die.
- 15. The method according to claim 14, wherein said bending step includes bending the hollow shaft in the radial direction completely around a circumference of the hollow shaft.
- 16. The method according to claim 15, further comprising the step of:folding the hollow shaft back onto itself to form a flange completely around the circumference of the hollow shaft.
- 17. The method according to claim 16, wherein the flange is located in approximately a center of a length of the hollow shaft.
- 18. The method according to claim 16, wherein the cylindrical opening has a depth and the cylindrical protruding portion has an extension length, and the depth is greater than the extension length.
- 19. A water pump for an engine comprising:a water pump body having an approximately cylindrical support section of a first diameter and a first length, wherein said first length is longer than said first diameter; a water pump shaft having a first end, a second end, and a second diameter, said second diameter being approximately equal to said first diameter, said water pump shaft lying within said cylindrical support section to be directly and rotatably attached to said water pump body; a water pump impeller included proximate said first end; and a notch formed in said second end of said water pump shaft for engaging with a protruding member adapted to mate within said notch for causing said water pump shaft and said water pump impeller to rotate relative to said water pump body.
- 20. The water pump according to claim 19, further comprising:a flange attached to an approximate center of said water pump shaft.
- 21. The water pump according to claim 20, wherein said flange is integrally formed as a part of said water pump shaft.
Priority Claims (1)
Number |
Date |
Country |
Kind |
10-279429 |
Sep 1998 |
JP |
|
US Referenced Citations (1)
Number |
Name |
Date |
Kind |
869887 |
Duryea |
Nov 1907 |
|