U.S. patent application number 10/387021 was filed with the patent office on 2003-11-13 for electrically motorized pump for use in water.
This patent application is currently assigned to Minebea Co., Ltd.. Invention is credited to Akiyama, Motoharu, Hokkirigawa, Kazuo.
Application Number | 20030210995 10/387021 |
Document ID | / |
Family ID | 27764524 |
Filed Date | 2003-11-13 |
United States Patent
Application |
20030210995 |
Kind Code |
A1 |
Hokkirigawa, Kazuo ; et
al. |
November 13, 2003 |
Electrically motorized pump for use in water
Abstract
The electrically motorized pump has a low energy loss because it
uses of the shaft and the sleeve made from synthetic resin
composition obtained by uniformly dispersing fine powder of RBC or
CRBC in a resin. The typical process for the production of a
synthetic resin composition for making the sleeve bearing for the
pump for use in water includes kneading with a resin the fine
powder of RBC or CRBC at a temperature in the neighborhood of the
melting point of the resin, and thereby uniformly dispersing the
fine powder of RBC or CRBC in the resin.
Inventors: |
Hokkirigawa, Kazuo;
(Sendai-Shi, JP) ; Akiyama, Motoharu; (Nagano-Ken,
JP) |
Correspondence
Address: |
SCHULTE ROTH & ZABEL LLP
ATTN: JOEL E. LUTZKER
919 THIRD AVENUE
NEW YORK
NY
10022
US
|
Assignee: |
Minebea Co., Ltd.
Nagano-Ken
JP
|
Family ID: |
27764524 |
Appl. No.: |
10/387021 |
Filed: |
March 12, 2003 |
Current U.S.
Class: |
417/423.12 |
Current CPC
Class: |
F04D 29/026 20130101;
F04D 29/047 20130101; F05D 2300/44 20130101; F04D 29/0465
20130101 |
Class at
Publication: |
417/423.12 |
International
Class: |
F04B 017/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 13, 2002 |
JP |
2002-069357 |
Claims
We claim:
1. An electrically motorized pump for use in a fluid comprising: a
motor; a pump; and at least one sleeve bearing wherein a portion of
the sleeve bearing is made of a synthetic resin composition
obtained by uniformly dispersing powder of RBC or CRBC in a resin,
the rotating parts of the motor and the pump being rotatably
supported by the sleeve bearing.
2. The electrically motorized pump of claim 1, wherein the motor
comprises: a stator; a housing with collar; and a can seal with
collar, the stator being located in an outer peripheral space
between the housing and the can seal.
3. The electrically motorized pump of claim 2, wherein the motor
further comprises: a rotor; a shaft; and at least one sleeve, the
shaft and the sleeve forming the sleeve bearing and the rotor being
rotatably supported by the sleeve bearing forming a rotor assembly,
the rotor assembly being located in an inner space of the can
seal.
4. The electrically motorized pump of claim 1, wherein a fluid may
freely flow from the impeller side to the rotor side.
5. The electrically motorized pump of claim 3, wherein the
synthetic resin composition has a ratio by mass of fine powder of
RBC or CRBC to the resin of 30 to 90:70 to 10.
6. The electrically motorized pump of claim 5, wherein the resin
used in making the sleeve bearing is selected from a group
consisting of nylon 66, nylon 6, nylon 11, nylon 12, poly acetal,
poly butylenes terephthalate, poly ethylene terephthalate, poly
propylene, poly ethylene, and poly phenylene sulfide.
7. The electrically motorized pump of claim 5, wherein the resin,
used in making the sleeve bearing includes at least two members of
the group consisting of nylon 66, nylon 6, nylon 11, nylon 12, poly
acetal, poly butylenes terephthalate, poly ethylene terephthalate,
poly propylene, poly ethylene, and poly phenylene sulfide.
8. The electrically motorized pump of claim 5, wherein the average
particle diameter of the powder of RBC or CRBC is 300 .mu.m or
less.
9. The electrically motorized pump of claim 8, wherein the average
particle diameter of the powder of RBC or CRBC is 10 to 50
.mu.m.
10. The electrically motorized pump of claim 8, wherein the shaft
is made of rust-resistant steel series metal.
11. The electrically motorized pump of claim 3, wherein the shaft
is made of the synthetic resin composition.
12. The electrically motorized pump of claim 11, wherein the resin
used in making the shaft is selected from a group consisting of
nylon 66, nylon 6, nylon 11, nylon 12, poly acetal, poly butylenes
terephthalate, poly ethylene terephthalate, poly propylene, poly
ethylene, and poly phenylene sulfide.
13. The electrically motorized pump of claim 11, wherein the resin
used in making the shaft includes at least two members of the group
consisting of nylon 66, nylon 6, nylon 11, nylon 12, poly acetal,
poly butylenes terephthalate, poly ethylene terephthalate, poly
propylene, poly ethylene, and poly phenylene sulfide.
14. The electrically motorized pump of claim 13, wherein the
average particle diameter of the fine powder of RBC or CRBC is 10
to 50 .mu.m.
15. The electrically motorized pump of claim 3, wherein the sleeve
of the sleeve bearing has at least one spiral groove on the inner
face of the sleeve.
16. The electrically motorized pump of claim 3, wherein the shaft
has at least one spiral groove on its surface.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This application claims priority based on Japanese patent
application No. 2002-069357, filed Mar. 13, 2002.
[0003] The present invention relates to an electrically motorized
pump for circulating cooling water in a water-cooled engine. More
particularly, the present invention relates to an electrically
motorized water pump that uses a sleeve bearing which offers a low
frictional coefficient in water.
[0004] 2. Description of the Related Art
[0005] A conventional water pump for pumping cooling water in a
closed cooling water circuit is driven by a crank shaft of an
engine. The cooling water circuit includes a water jacket of the
engine connected to a radiator of the engine. Such a conventional
pump's rotation corresponds to the number of revolutions of the
engine. The number of revolutions of such pump could not be
controlled in a fine manner. Furthermore, when the engine stops,
the pump stops immediately thereby causing troubles.
[0006] On the other hand, if a pump for use with water is driven by
an electric motor, it is possible to arbitrarily control the number
of revolutions and keep it running even when the engine is stopped.
It is also possible to arbitrarily control the flow volume of
cooling water passing through a radiator by electrically varying
the degree of opening of a thermostatically controlled valve. Such
a cooling control device for an engine has been disclosed in
Japanese Laid Open Patent Gazette, Laid Open Publication No. Hei
5/1993-231148.
[0007] The conventional electrically motorized pump for use with
water has a structure in which the impeller side and the rotor side
of a pump are sealed to prevent water from flowing through. An O
ring made of rubber is placed between the impeller side and the
rotor side or a sealing material is allowed to be in close contact
with a rotary shaft. When the rotor is used at high revolutions for
a long period of time, the O ring deteriorates causing a loss in
energy, also the sealing material, which is in close contact with
the shaft causes a loss in energy.
[0008] One object of the present invention is to provide an
electrically motorized pump for use in water which does not require
any seal between the impeller side and the rotor side of a pump,
allows water to freely flow therethrough, has low power
consumption, and allows cooling water to circulate efficiently in a
water-cooled engine.
[0009] The objects are achieved by improving upon materials
described in an article by Mr. Kazuo Horikirigawa (Kinou Zairyou
(Functional Materials), May 1997 issue, Vol. 17, No. 5, pp 24 to
28) that discloses a porous carbon material made by using rice
bran, which is called "RB ceramic" (hereinafter referred to as
"RBC"). RBC is a carbon material obtained by mixing and kneading
defatted rice bran and a thermosetting resin, and then by molding
the mixture and sintering it in an inert gas atmosphere after
drying the compact. Any thermosetting resin including a phenol
resin, a diaryl phthalate resin, an unsaturated polyester resin, an
epoxy resin, a poly imide resin, or a triazine resin may be used.
Phenol resin being the preferred material. The mixing ratio between
defatted rice bran and the thermosetting resin is 50 to 90:50 to 10
by mass, 75:25 being the preferred ratio. Sintering is done at
700.degree. C. to 1000.degree. C. for about 40 minutes to 120
minutes using, for example, a rotary kiln.
[0010] CRB ceramic (hereinafter referred to as "CRBC") is a black
colored porous ceramic obtained by further improving RBC as
follows: after mixing and kneading defatted rice bran and a
thermosetting resin, and then preliminarily sintering the mixture
at a temperature of 700.degree. C. to 1000.degree. C. in an inert
gas atmosphere, the mixture is pulverized to about 100 mesh or less
to generate a carbonized powder. Next, the carbonized powder and a
thermosetting resin are mixed and kneaded, and after molding it
under pressure of 20 Mpa to 30 Mpa, the molded substance is again
heat treated at a temperature of 500.degree. C. to 1100.degree. C.
in an inert gas atmosphere to obtain CRBC.
[0011] RBC and CRBC have the following excellent
characteristics:
[0012] High hardness.
[0013] The surface of each particle is irregular.
[0014] Extremely small coefficient of thermal expansion.
[0015] The textural constitution is porous.
[0016] Conducts electricity.
[0017] The specific gravity is low and it is light in weight.
[0018] Extremely small coefficient of friction.
[0019] Excellent anti-wearing property.
[0020] As the raw material is rice bran, its adverse effects on the
earth's environment are minor, and it leads to the resource
saving.
SUMMARY OF THE INVENTION
[0021] The shortcomings of the prior art are overcome by the
present invention by providing an electrically motorized pump for
use in water. The pump has a stator accommodated in an outer
peripheral space between a housing with a collar and a can seal
with a collar. A rotor, a rotary shaft, and a sleeve bearing are
accommodated in the inner space of the can seal. The sleeve bearing
is attached to a central hole of a base plate of a pump casing.
Said base plate, a collar section of the housing and the can seal
are attached to each other. An impeller attached to a tip section
of the rotary shaft is located in the inner side of the pump
casing. The electrically motorized pump has a low energy loss
because it uses a shaft and a sleeve made from a synthetic resin
composition obtained by uniformly dispersing a fine powder of RBC
or CRBC in a resin.
[0022] The synthetic resin composition obtained by mixing the RBC
or CRBC in form of fine a powder of an average particle diameter of
300 .mu.m or less, preferably 10 to 100 .mu.m, more preferably 10
to 50 .mu.m, and a resin displays specific desirable sliding motion
characteristics. In particular the synthetic resin composition
obtained by uniformly dispersing a fine powder of RBC or CRBC,
especially at a ratio by mass of the fine powder of RBC or
CRBC:resin, of 30 to 90:70 to 10 displays surprisingly good wear
characteristics with anti-rust property in water, alcohol, ethylene
glycol and a mixture thereof.
[0023] The typical process for the production of a synthetic resin
composition for making the sleeve bearing for the pump for use in
water includes kneading with a resin the fine powder of RBC or CRBC
at a temperature in the neighborhood of the melting point of the
resin, and thereby uniformly dispersing the fine powder of RBC or
CRBC in the resin. The RBC can also be made using materials other
than rice bran that can be a source of carbon. One example of such
material is bran of another grain such as oat.
[0024] Further features and advantages will appear more clearly on
a reading of the detailed description, which is given below by way
of example only and with reference to the accompanying drawings
wherein corresponding reference characters on different drawings
indicate corresponding parts.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] FIG. 1 is a schematic drawing showing the assembly of a pump
for use in water.
[0026] FIG. 2 is a cross sectional view of the pump for use in.
[0027] FIG. 3 is one example of a shaft of a sleeve bearing.
[0028] FIG. 4 is one example of a shaft of a sleeve bearing.
DETAILED DESCRIPTION
[0029] FIG. 1 is a schematic drawing showing the assembly of a pump
for use in water. Sleeve bearings 2 and 2' are slidably Mounted a
the rotary shaft 1-1. A rotor 1' is attached to rotary shaft 1-1 to
form a rotor assembly 1. An impeller 4 is mounted at the tip
section of rotary shaft 1-1 and protrudes into pump easing 5 from a
central section 3 of pump casing 5 through an O-ring 11. On the
other hand, a stator assembly 8 for the rotation of rotor 1 is
tightly sealed in a water tight outer peripheral space formed by a
can seal 9 with a collar and a housing 6 with a collar so as to
prevent water from penetrating. A hole sensor assembly 7 is placed
within housing 6. Rotor assembly 1 is placed within can seal 9. A
pump assembly is made by attaching together housing 6, central
section 3 and pump casing 5 through O-ring 11 by means of a fixing
means such as a screw, or a bolt and a nut. The pump assembly so
formed allows fluid from impeller side to flow to the rotor
side.
[0030] FIG. 2 shows the cross sectional view of the pump for use
with water. When an electric current is allowed to flow through
stator assembly 8, rotor 1 rotates, thereby rotating rotary shaft
1-1 and impeller 4 and thus water is taken in and sent to the
cooling section of an engine. Sleeve bearing 2 consists of shaft
1-1 and sleeve 2-2. Either one or both of Shaft 1-1 and Sleeve 2-2
are formed by molding a synthetic resin composition obtained by
uniformly dispersing fine powder of RBC or CRBC in a resin.
[0031] In one embodiment shaft 1-1 is made of an alloy from the
stainless steel family. If a hard shaft is required, quenching is
carried out. As shown in FIG. 4, if necessary, it is permissible to
press a hard anti-rusting alloy sleeve 1-2 in portion of shaft 1-1.
Non limiting examples of steel series metal that may be used for
making shaft 1-1 or sleeve 2-2 are stainless steel type alloy of
iron, nickel, chrome, and molybdenum. Any alloy, as long as it is
hard and difficult to rust, can be used. Furthermore, it is also
permissible to make shaft 1-1 with the above-mentioned synthetic
resin composition.
[0032] The RBC or CRBC has an average particle diameter of 300
.mu.m or less. Average particle diameter of 10 to 100 .mu.m, more
preferably 10 to 50 .mu.m, allows a surface condition of a good
frictional coefficient to be formed, and is appropriate as a
material for a sleeve bearing for sliding motion in water.
[0033] Resins such as, for example, poly amide, polyester, and poly
olefin can be used with RBC or CRBC to obtain synthetic resin
composition. Thermoplastic resins such as nylon 66 (poly hexa-
methylene adipamide), nylon 6 (poly capramide), nylon 11 (poly
undecane amide), nylon 12, poly acetal, poly butylenes
terephthalate, poly ethylene terephthalate, poly propylene, poly
ethylene, and poly phenylene sulfide can also be used with RBC or
CRBC to obtain the synthetic resin composition, nylon 66 being
preferred. These thermoplastic resins can be used alone or a
mixture of two or more may be used. Thermosetting resin alone or in
combination with other resins can be used with RBC or CRBC to
obtain synthetic resin composition. Non-limiting examples of such
thermosetting resins are diaryl phthalate resin, an unsaturated
polyester resin, an epoxy resin, a poly imide resin, or a triazine
resin. RBC can also be made from materials other than rice bran
that can be source of carbon. One example of such material is bran
of another grain such as oat. The ratio by mass of fine powder of
RBC or CRBC to resin is 30 to 90:70 to 10. If the amount of a resin
or a combination of resins exceeds 70% by mass, the low frictional
characteristics can not be achieved, on the other hand, if a resin
or a combination of resins is 10% by mass or less, the molding
becomes difficult.
[0034] The molding is in general done by extrusion molding or
injection molding. The preferred temperature of the mold die is on
a slightly lower side between the glass transition point and the
melting point of the resin. Furthermore, good frictional property
can be obtained by gradual cooling of the mold die.
[0035] The following examples explain the details of the present
invention.
EXAMPLE 1
[0036] Manufacturing Example of RBC Fine Powder
[0037] 750 grams of defatted rice bran and 250 grams of a phenol
resin in liquid form (Resol) were mixed and kneaded while heating
them at a temperature of 50.degree. C. to 60.degree. C. A uniform
mixture having plasticity was obtained. The mixture was baked for
100 minutes at a temperature of 900.degree. C. in a nitrogen
atmosphere in a rotary kiln, and the carbonated baked product thus
obtained was pulverized in a pulverizing machine. The pulverized
product was sieved through a sieve of 150 mesh to obtain a fine
powder of RBC having an average particle diameter of 140 to 160
.mu.m.
[0038] Example of Preparation 1 of a Composition of RBC Fine Powder
and a Resin
[0039] While heating at a temperature of 240.degree. C. to
290.degree. C., 500 grams of the RBC fine powder thus obtained and
500 grams of nylon 66 powder were mixed and kneaded. Thus a uniform
plastic mixture having 50% by mass of the RBC fine powder was
obtained.
[0040] Preparation of a Sleeve Bearing and Application Thereof to a
Pump for Use in Water
[0041] The synthetic resin composition obtained by melting and
mixing the RBC fine powder and nylon 66 was injection molded,
thereby preparing a sleeve of 22 mm in outer diameter, 8 mm in
inner diameter, and 20 mm in length. A shaft of 7.95 mm in outer
diameter and 200 mm in length made of SUS 303 stainless alloy was
inserted into the molded sleeve, thereby preparing a sleeve bearing
as shown in FIG. 3. As shown in FIG. 1 and FIG. 2, this sleeve was
used in the sleeve bearings 2 and 2' for a rotor assembly.
EXAMPLE 2
[0042] By using the method described in Example 1, RBC fine powder
of an average particle diameter of 140 to 160 .mu.m was
obtained.
[0043] Example of Preparation 2 of a Composition of RBC Fine Powder
and a Resin
[0044] While heating at a temperature of 240.degree. C. to
290.degree. C., 700 grams of the RBC fine powder thus obtained and
300 grams of nylon 66 powder were mixed and kneaded. Thus a uniform
plastic mixture having 70% by mass of the RBC fine powder was
obtained.
[0045] Preparation of a Sleeve Bearing and Application Thereof to a
Pump for Use in Water
[0046] The synthetic resin composition obtained by melting and
mixing the RBC fine powder and nylon 66 was injection molded,
thereby preparing a sleeve of 22 mm in outer diameter, 8 mm in
inner diameter, and 20 mm in length. A shaft of 7.95 mm in outer
diameter and 200 mm in length made of SUS 304 stainless alloy was
inserted into the molded sleeve, thereby preparing a sleeve bearing
as shown in FIG. 3. As shown in FIG. 1 and FIG. 2, this sleeve was
used in sleeve bearings 2 and 2' of a rotor assembly.
EXAMPLE 3
[0047] Manufacturing Example 3 of RBC Fine Powder
[0048] 750 grams of defatted rice bran and 250 grams of a phenol
resin in a liquid form (Resol) were mixed and kneaded while heating
them at a temperature of 50.degree. C. to 60.degree. C. A uniform
mixture having plasticity was obtained. The mixture was baked for
100 minutes at a temperature of 1000.degree. C. in a nitrogen
atmosphere in a rotary kiln, and the carbonated baked product thus
obtained was pulverized in a pulverizing machine, followed by
sieving with a sieve of 400 mesh, and thus fine powder of RBC
having an average particle diameter of 40 to 50 .mu.m was
obtained.
[0049] Example of Preparation 3 of a Composition of RBC Fine Powder
and a Resin
[0050] While heating at a temperature of 240.degree. C. to
290.degree. C., 700 grams of the RBC fine powder thus obtained and
300 grams of nylon 66 powder were mixed and kneaded. Thus a uniform
plastic mixture having 70% by mass of the RBC fine powder was
obtained.
[0051] Preparation of a Sleeve Bearing and Application Thereof to
Pump for Use in Water
[0052] The synthetic resin composition obtained by melting and
mixing the RBC fine powder and nylon 66 was injection molded,
thereby preparing a sleeve of 22 mm in outer diameter, 8 mm in
inner diameter, and 20 mm in length. A shaft of 7.95 mm in outer
diameter and 200 mm in length made of SUS bearing steel was
inserted into the molded sleeve, thereby preparing a sleeve bearing
as shown in FIG. 3. As shown in FIG. 1 and FIG. 2, it was used as
sleeve bearings 2 and 2' of a rotor assembly.
EXAMPLE 4
[0053] Manufacturing Example of CRBC Fine Powder
[0054] 750 grams of defatted rice bran and 250 grams of a phenol
resin in a liquid form (Resol) were mixed and kneaded while heating
them at a temperature of 50.degree. C. to 60.degree. C. A uniform
mixture having plasticity was obtained. The mixture was baked for
60 minutes at a temperature of 900.degree. C. in a nitrogen
atmosphere in a rotary kiln. And the carbonated baked product thus
obtained was pulverized in a pulverizing machine, followed by
sieving with a sieve of 200 mesh, and thus fine powder of RBC
having an average particle diameter of 100 to 120 .mu.m was
obtained.
[0055] While heating at a temperature of 100.degree. C. to
150.degree. C., 750 grams of the RBC fine powder thus obtained and
500 grams of a phenol resin in a solid form (Resol) were mixed and
kneaded. Thus a uniform mixture having plasticity was obtained.
Then, the plastic material was molded under pressure into a sphere
of about 1 cm in diameter under a pressure of 22 Mpa. The
temperature of the mold die was 150.degree. C. The molded product
was taken out from the mold die and placed in a kiln, the
temperature of the molded product was raised to 500.degree. C. in a
nitrogen atmosphere at a rate of 1.degree. C. per minute, and it
was kept at 500.degree. C. for 60 minutes, and then sintered at
900.degree. C. for about 120 minutes. Then, the temperature was
lowered to 500.degree. C. at a rate of 2 to 3.degree. C. per
minute, and after reaching 500.degree. C. or lower, it was cooled
naturally while leaving it undisturbed. The CRBC molded product
thus obtained was pulverized in a pulverizing machine, followed by
sieving with a sieve of 500 mesh to obtain CRBC fine powder having
an average particle diameter of 20 to 30 .mu.m.
[0056] Example of Preparation of a Composition of CRBC Fine Powder
and a Resin
[0057] While heating at a temperature of 240.degree. C. to
290.degree. C., 500 grams of the CRBC fine powder thus obtained and
500 grams of nylon 66 powder were mixed and kneaded. Thus a uniform
plastic mixture having 50% by mass of the CRBC fine powder was
obtained.
[0058] Preparation of a Sleeve Bearing and Application Thereof to a
Pump for Use in Water
[0059] The synthetic resin composition obtained by melting and
mixing the CRBC fine powder and nylon 66 was injection molded into
a sleeve of 22 mm in outer diameter, 8 mm in inner diameter, and 20
mm in length. A 200 mm long shaft is made by pressing two
cylindrical members of 7.95 mm in outer diameter, 5.00 in inner
diameter and 20 mm in length and made of SUS 304 stainless alloy
into both ends of the shaft. The shaft was inserted into the molded
sleeves, thereby preparing a sleeve bearing as shown in FIG. 4. It
was used for sleeve bearings 2 and 2' of the rotor assembly shown
in FIG. 1 and FIG. 2.
[0060] The compositions of RBC or CRBC and resins used in Example 5
through Example 9 were prepared by using the same RBC or CRBC fine
powder as produced in Example 1 through Example 4 and by dispersing
the fine powder of the RBC or the CRBC in resins under the
conditions as indicated in Table 1. In addition, for the sake of
comparison, commercially available PPS resin for pumps used in
water (made by Idemitsu Sekiyu Kagaku K., K. Co., Ltd.) was
used.
1 TABLE 1 Composition Composition Composition Composition
Composition 5 6 7 8 9 Ex. For comp. Types of RBC One used in One
used in One used in One used in One used in -- and CRBC Ex. 4 Ex. 3
Ex. 1 Ex. 2 Ex. 2 fine powder Synthetic Nylon 66 PBT PP PPS Nylon
66 PPS resin Finepowder: 70:30 50:50 70:30 50:50 30:70 -- resin
(ratio by mass) PBT: poly butylenes terephthalate PP: polypropylene
PPS: poly phenylene sulfide
[0061] The characteristics of the compositions of the RBC or CRBC
fine power, and resins, and the PPS resin used in the sleeve
bearing for use in water of Example 1 through Example 9 are
summarized in Table 2.
2 TABLE 2 Tensile strength Bending strength Bending Resistivity
(ohm Specific (MPa) (MPa) elasticity (GPa) cm) gravity Composition
of Ex. 1 64.6 98.6 6.12 4.9 E+01 1.35 Composition of Ex. 2 61.4
97.6 6.14 3.2E+01 1.38 Composition of Ex. 3 76.5 120 8.85 2.1E+01
1.43 Composition of Ex. 4 75.9 117 8.56 3.4E+01 1.38 Composition of
Ex. 5 58.2 105 4.12 3.3E+01 1.27 Composition of Ex. 6 49.6 72.3 7.5
3.3E+01 1.46 Composition of Ex. 7 22.7 44.3 6.5 3.8E+01 1.32
Composition of Ex. 8 79.2 121 7.6 4.0E+01 1.48 Composition of Ex. 9
57.3 101 4.3 2.7E+01 1.24 PPS in Ex. For compar. 159 235 14.1
1.0E+16 1.75
EXAMPLE 5
[0062] The synthetic resin composition 5 listed in Table 1 was
injection molded, thereby preparing a sleeve of 22 mm in outer
diameter, 8 mm in inner diameter, and 20 mm in length having a
spiral groove of 0.1 mm in depth on the inner side. A shaft of 7.95
mm in outer diameter and 200 mm in length made of SUS bearing steel
was inserted into the molded sleeves, thereby preparing sleeve
bearings shown in FIG. 3. These sleeve bearings were used for
sleeve bearings 2 and 2' of the rotor assembly shown in FIG. 1 and
FIG. 2.
EXAMPLE 6
[0063] The synthetic resin composition 6 listed in Table 1 was
injection molded, thereby preparing a shaft of 7.95 mm in outer
diameter, and 200 mm in length. Sleeves 22 mm in outer diameter, 8
mm in inner diameter, and 120 mm in length were made from SUS
bearing steel. The sleeves were inserted on the shaft to form
sleeve bearings as shown in FIG. 3. These sleeve bearings were used
for sleeve bearings 2 and 2' of the rotor assembly shown in FIG. 1
and FIG. 2.
EXAMPLE 7
[0064] The synthetic resin composition 7 listed in Table 1 was
injection molded, thereby preparing a shaft of 7.95 mm in outer
diameter, and 200 mm in length having a spiral groove of 0.1 mm in
depth. Sleeves 22 mm in outer diameter, 8 mm in inner diameter and
20 mm in length were made from SUS bearing steel. The sleeves were
inserted on the shaft to form sleeve bearings as shown in FIG. 3.
These sleeve bearings were used for sleeve bearings 2 and 2' of the
rotor assembly shown in FIG. 1 and FIG. 2.
EXAMPLE 8
[0065] The synthetic resin composition 8 listed in Table 1 was
injection molded, to prepare two sleeves of 22 mm in outer
diameter, 8 mm in inner diameter, and 20 mm in length. A shaft of
7.95 mm in outer diameter and 200 mm in length made of SUS bearing
steel having a spiral groove of 0.1 mm in depth was inserted into
the sleeves, thereby preparing sleeve bearings as shown in FIG. 3.
These sleeve bearings were used for sleeve bearings 2 and 2' of the
rotor assembly shown in FIG. 1 and FIG. 2.
EXAMPLE 9
[0066] The synthetic resin composition 9 listed in Table 1 was
injection molded, thereby preparing a shaft of 7.95 mm in outer
diameter, and 200 mm in length having a spiral groove of 0.1 mm in
depth. Sleeves 22 mm in outer diameter, 8 mm in inner diameter and
20 mm in length were made from SUS bearing steel. The sleeves were
inserted on the shaft to form sleeve bearings as shown in FIG. 3.
These sleeve bearings were used for sleeve bearings 2 and 2' of the
rotor assembly shown in FIG. 1 and FIG. 2.
[0067] Example for Comparison
[0068] The commercially available PPS resin for pump for use with
water (made by Idemitsu Sekiyu Kagaku K., K., Co., Ltd.) was
injection molded, thereby preparing sleeves 22 mm in outer
diameter, 8 mm in inner diameter and 20 mm in length. A shaft of
7.95 mm in outer diameter and 200 mm in length made of SUS 303
stainless alloy was inserted into the sleeves, thereby preparing a
sleeve bearing as shown in FIG. 3. These sleeve bearings were used
for sleeve bearings 2 and 2' of the rotor assembly shown in FIG. 1
and FIG. 2.
[0069] The frictional characteristics in water of the sleeve
bearings for sliding motion in water obtained in Example 1 through
Example 9 and in Example for Comparison are summarized in Table
3.
3 TABLE 3 Ex. For Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6 Ex. 7 Ex. 8
Ex. 9 compare Shape of Sleeve bearing helix Frictiona 0.212 0.198
0.259 0.221 0.231 0.288 0.232 0.288 0.268 0.406 1 coeff. .mu. A
Frictiona 0.182 0.212 0.234 0.209 0.239 0.268 0.195 0.259 0.252
0.413 1 coeff. .mu. B Frictiona 0.194 0.195 0.238 0.184 0.228 0.268
0.188 0.213 0.244 0.388 1 coeff. .mu. C Frictiona 0.138 0.167 0.211
0.177 0.172 0.229 0.162 0.198 0.212 0.259 1 coeff. .mu. D Frictiona
0.156 0.182 0.204 0.195 0.172 0.213 0.159 0.156 0.218 0.213 1
coeff. .mu. E Frictiona 0.148 0.153 0.204 0.152 0.153 0.187 0.168
0.177 0.196 0.248 1 coeff. .mu. F A. measured under the condition
of a sliding speed of 0.001 m / sec B. measured under the condition
of a sliding speed of 0.005 m / sec C. measured under the condition
of a sliding speed of 0.01 m / sec D. measured under the condition
of a sliding speed of 0.1 m / sec E. measured under the condition
of a sliding speed of 0.5 m / sec F. measured under the condition
of a sliding speed of 1 m / sec
[0070] As can be clearly seen from the results given in Table 3,
the pumps for use with water which use the sleeve bearings made
from the synthetic resin compositions of fine powder of RBC and
CRBC and the resins are markedly excellent in frictional
characteristics in water. Additionally, an electrically motorized
pump for use in water which does not require any seal between the
impeller side and the rotor side of a pump, allows a water fluid to
freely flow, saves power consumption, allows cooling water for a
water-cooled engine to be effectively circulated and is low in
energy loss.
[0071] While a preferred embodiment of the invention has been
described, various modifications will be apparent to one skilled in
the art in light of this disclosure and are intended to fall within
the scope of the appended claims.
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