Support apparatus for movable member and pump apparatus

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a support apparatus provided with a member for displaceably supporting a movable member such as a rotating shaft, and a pump apparatus.

2. Description of the Related Art

Space equipment such as artificial satellites, space stations or the like, and other equipment used in outer space include many kinds of drive mechanisms in which a support apparatus, such as ball-and-roller bearing apparatuses, ball screw apparatuses, linear guide apparatuses and the like, for displaceably supporting a movable member is used. Fluoro grease is used as a lubricant in a support apparatus for use on earth, but evaporates in outer space is responsible for contamination of various equipment and decomposition due to radioactive rays, and so cannot be used there. In a support apparatus for equipment used in outer space, molybdenum dioxide, lead or silver is used, which is low in torque and stable.

As described above, equipment used in outer space, in particular, equipment used over a long term in artificial satellites, space stations or the like, are exceedingly difficult in the exchange of parts, and required high durability. A support apparatus for supporting a movable member provided in such equipment is desirably made simple in construction for the purpose of less failure, and constructed to dispense with the use of lubricant for preventing a degraded performance due to changes in the lubricant.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a support apparatus which is simple in construction and dispenses with lubricant.

Also, it is an object of the invention to provide a pump apparatus which is simple in construction and provided with a bearing structure for supporting a rotating shaft, and which dispenses with lubricant.

The invention provides a support apparatus for displaceably supporting a movable member comprising slide members for slidably supporting the movable member, the slide members being formed of amorphous carbon.

According to the invention, a movable member can be supported by slide members formed of amorphous carbon. Amorphous carbon is high in abrasion resistance and possesses a low frictional property called a self-lubricating property, and slide members formed of amorphous carbon are used to smoothly slide relative to a movable member to, without using lubricant, enable supporting the movable member so that the movable member can be smoothly displaced. Accordingly, it is possible to obtain a support apparatus that is simple in construction and supports a movable member without the use of lubricant to enhance the durability of the support apparatus.

In the invention, it is preferable that the movable member comprises a rotating shaft and the slide members are slide bearing members for rotatably supporting the rotating shaft.

According to the invention, the slide bearing members formed of amorphous carbon can support the rotating shaft. It thereby is possible to reduce a gap between the rotating shaft and the slide bearing members and rotatably support the rotating shaft so as to cause stable rotation of the rotating shaft.

In the invention it is preferable that the slide members are arranged in a space in which a fluid is contained.

According to the invention, the slide members are formed of amorphous carbon and possess chemical resistance, so they are not subjected to chemical change by a fluid even when being provided in a space in which a fluid is contained. Besides, even if the fluid is one, either a strong acid or strong base, liable to chemically affect a mating member, the slide members are not subjected to chemical change by the fluid. The slide members can thereby preserve the function as slide members over a long term without being damaged by the fluid. Accordingly, the slide members can be suitably used in fluid flow passages.

In the invention, it is preferable that a gap between the movable member and the slide members is dimensioned to allow entry of the fluid due to the capillary phenomenon.

According to the invention, a fluid in the space enters between the movable member and the slide members. The slide members formed of amorphous carbon are not restricted in lubricant as in the case of slide members of metal, but can use a wide variety of fluids as lubricant. As described above, while lubricant is essentially unnecessary, the use of lubricant makes it possible to support the movable member in a further smoothly displaceable manner. Accordingly, a fluid in the gap can be used as lubricant so that a supporting state can be achieved to realize smooth displacement of the movable member.

In the invention, it is preferable that the fluid is liquid ammonia. According to the invention, the slide members possess chemical resistance, and are not subjected to chemical change even when a fluid is liquid ammonia, so that they can preserve their function as slide members over a long term. Moreover, it is possible to make use of liquid ammonia as a favorable lubricant. Accordingly, the slide bearing members can be favorably used in a space in which liquid ammonia is contained.

In the invention it is preferable that the support apparatus is mounted on equipment used in outer space.

According to the invention, the support apparatus can be enhanced in durability, so that it is suitably usable for equipment, such as artificial satellites, space stations or the like, which are used in outer space, and whose parts are difficult to exchange.

The invention provides a pump apparatus comprising a rotating shaft, slide bearing members formed of amorphous carbon for rotatably supporting the rotating shaft, drive means for drivingly rotating the rotating shaft and a pump body connected to the rotating shaft, for pumping a fluid.

According to the invention, the drive means is used to drive the rotating shaft to drive the pump body connected to the rotating shaft to discharge a fluid. The rotating shaft is rotatably supported by a bearing apparatus having slide bearing members. The slide bearing members are formed of amorphous carbon. Amorphous carbon is high in abrasion resistance and possesses a low frictional property called a self-lubricating property, and slide bearing members formed of amorphous carbon are used to smoothly slide relative to the rotating shaft to, without using lubricant, enable supporting the rotating shaft so that the rotating shaft can be smoothly rotated. Accordingly, it is possible to obtain a bearing apparatus which is simple in construction and supports the rotating shaft without the use of lubricant to enhance durability of the bearing apparatus, thus of the pump apparatus.

In the invention it is preferable that the pump apparatus further comprises a housing having a fluid flow passage which provides communication between a suction port and a discharge port, and that the rotating shaft is arranged in the housing, the slide bearing members are fitted in the fluid flow passage in the housing, the drive means comprises a rotor fitted in the fluid flow passage to be provided on the rotating shaft and a stator provided outside the housing to surround the rotor, and the pump body is provided midway of the fluid flow passage.

According to the invention, the drive means is used to drive the rotating shaft to drive the pump body connected to the rotating shaft so that a fluid sucked through a suction port is made to flow down the flow passage to be discharged through a discharge port. In this pump apparatus, the rotating shaft, the slide bearing members and the rotor are fitted into the flow passage. In this manner, the provision of the rotating shaft, the slide bearing members and the rotor in the flow passage eliminates the need of providing rotating constituents both inside and outside the flow passage through the housing, so that the whole pump apparatus can be made favorable in sealing quality relative to leakage of the fluid, the sealing construction can be made simple, and the pump apparatus can be made small in size.

With such construction, the slide bearing members are formed of amorphous carbon and possess chemical resistance, so they are not subjected to chemical change by a fluid even when being provided in a space in which a fluid is contained. Besides, even if the fluid is one, either strong acid or strong base, liable to chemically affect a mating member, the slide members are not subjected to chemical change by the fluid. The slide bearing members can thereby preserve the function as slide bearing members over a long term without damage by the fluid.

In the invention, it is preferable that a gap between the rotating shaft and the slide bearing members is dimensioned to allow entry of the fluid due to the capillary phenomenon.

According to the invention, a fluid in the flow passage enters between the rotating shaft and the slide bearing members. The slide bearing members formed of amorphous carbon are not restricted in lubricant as in the case of slide bearing members of metal, but can use a wide variety of fluids as lubricant. As described above, while lubricant is essentially unnecessary, the use of lubricant makes it possible to support the rotating shaft in a further smoothly displaceable manner. Accordingly, the fluid in the flow passage can be used as lubricant and so a pump apparatus can be achieved to provide for further smooth rotation of the rotating shaft.

In the invention it is preferable that the pump apparatus is a pump for circulating a refrigerant and the fluid is liquid ammonia as the refrigerant.

According to the invention, the slide bearing members possess chemical resistance, and are not subjected to chemical change even when the fluid is liquid ammonia, so that they can preserve the function as slide bearing members over a long term. Moreover, the slide bearing members can make use of liquid ammonia as a favorable lubricant. Without the use of freon gas, for the sake of global environmental protection, such liquid ammonia is used as a refrigerant favorably in the pump apparatus, in which the refrigerant is circulated.

Also, liquid ammonia as refrigerant can be used to cool the rotating shaft, the slide bearing members and the rotor and to maintain a stable performance of the pump.

In the invention it is preferable that the pump body is formed of amorphous carbon.

According to the invention, the pump body is formed of amorphous carbon, and so is not susceptible to chemical influences, whereby it is possible to realize a favorable pump apparatus that keeps the function of the pump body over a long term.

In the invention, it is preferable that the slide bearing members are radial bearings to bear the radial load of the rotating shaft, and the pump body is formed of amorphous carbon to bear the thrust load of the rotating shaft.

According to the invention, formation of the pump body of amorphous carbon can have the pump body fulfilling the function of thrust bearings and bearing the thrust load of the rotating shaft. Therefore, the load on the slide bearing members can be reduced. In this manner, load is imposed on the pump body to make it possible to reduce the slide bearing members in size and enhance durability of the pump apparatus.

In the invention, it is preferable that the pump apparatus is mounted on equipment used in outer space.

According to the invention, the pump apparatus can be enhanced in durability so that it is suitably usable for equipment, such as artificial satellites, space stations or the like, which are used in outer space, of which parts are difficult to exchange.

BRIEF DESCRIPTION OF THE DRAWINGS

Other and further objects, features, and advantages of the invention will be more explicit from the following detailed description taken with reference to the drawings wherein:

FIG. 1

is a cross sectional view showing a pump apparatus

1

according to an embodiment of the invention;

FIG. 2

is a cross sectional view of the pump apparatus

1

of

FIG. 1

as viewed from above of

FIG. 1

;

FIG. 3

is a left side view of the pump apparatus

1

of

FIG. 1

;

FIG. 4

is a right side view of the pump apparatus

1

of

FIG. 1

;

FIG. 5

is a front view showing a cylindrical-shaped member

11

constituting a housing

3

;

FIG. 6

is a right side view of the cylindrical-shaped member

11

of

FIG. 5

;

FIG. 7

is a cross sectional view showing a pump chamber forming member

12

constituting the housing

3

;

FIG. 8

is a plan view of the pump chamber forming member

12

of

FIG. 7

;

FIG. 9

is a left side view of the pump chamber forming member

12

of

FIG. 7

;

FIG. 10

is a right side view of the pump chamber forming member

12

of

FIG. 7

;

FIG. 11

is a cross sectional view of a suction port forming member

13

constituting the housing

3

;

FIG. 12

is a left side view of the suction port forming member

13

of

FIG. 11

;

FIG. 13

is a right side view of the suction port forming member

13

of

FIG. 11

;

FIG. 14

is a cross sectional view showing a discharge port forming member

14

constituting the housing

3

;

FIG. 15

is a right side view of the discharge port forming member

14

of

FIG. 14

;

FIG. 16

is a front view showing a rotating shaft

4

;

FIG. 17

is a left side view of the rotating shaft

4

of

FIG. 16

;

FIG. 18

is a cross sectional view showing slide bearing members

5

;

FIG. 19

is a left side view of the slide bearing members

5

of

FIG. 18

;

FIG. 20

is a front view showing an inner gear

60

;

FIG. 21

is a cross sectional view taken along cutting plane line S

21

—S

21

in

FIG. 20

;

FIG. 22

is a front view showing an outer gear

61

;

FIG. 23

is a cross sectional view taken along cutting plane line S

23

—S

23

in

FIG. 22

;

FIG. 24

is a cross sectional view showing a pump body

10

on an enlarged scale;

FIG. 25

is a cross sectional view of the pump body

10

as viewed from leftward of

FIG. 24

;

FIG. 26

is an exploded, perspective view showing the pump body

10

;

FIG. 27

is a cross sectional view showing an apparatus for measuring coefficients of friction;

FIGS. 28A and 28B

are graphs showing results of tests for measuring coefficients of friction;

FIG. 29

is a cross sectional view showing an apparatus for measuring wear in the air;

FIGS. 30A and 30B

are graphs showing results of tests for measuring wear in the air;

FIG. 31

is a cross sectional view showing an apparatus for measuring wear in the water;

FIGS. 32A and 32B

are graphs showing results of tests for measuring wear in the water;

FIG. 33

is a graph showing wear coefficients of various materials including AC;

FIG. 34

is a graph showing coefficients of thermal expansion of various materials including AC;

FIG. 35

is a graph showing bulk densities of various materials including AC;

FIG. 36

is a graph showing melting points or temperatures of thermal deformation of various materials including AC;

FIG. 37

is a graph showing the relationship between discharge pressure and flow rate of the pump apparatus

1

making use of water at 5.5° C.;

FIG. 38

is a graph showing the relationship between discharge pressure and flow rate of the pump apparatus

1

making use of ethyl ether;

FIG. 39

is a graph showing the relationship between discharge pressure and flow rate of the pump apparatus

1

making use of liquid ammonia at 8° C.;

FIG. 40

is a graph showing the relationship between discharge pressure and flow rate of the pump apparatus

1

making use of ethyl ether at 10° C.;

FIG. 41

is a graph showing the relationship between input power to a drive means and flow rate of the pump apparatus

1

making use of ethyl ether at 10° C.; and

FIG. 42

is a graph showing the relationship between number of revolutions and flow rate of the pump apparatus

1

making use of ethyl ether at 10° C.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Now referring to the drawings, preferred embodiments of the invention are described below.

FIG. 1

is a cross sectional view showing a pump apparatus

1

according to an embodiment of the invention,

FIG. 2

being a cross sectional view showing the pump apparatus

1

as viewed from above

FIG. 1

,

FIG. 3

being a left side view showing the pump apparatus

1

of

FIG. 1

, and

FIG. 4

being a right side view showing the pump apparatus

1

of FIG.

1

. The pump apparatus

1

is an apparatus for feeding a liquid, the apparatus being mounted on, for example, space equipment such as artificial satellites, space stations or the like, and equipment used in outer space outside the stratosphere, and serves to circulate a refrigerant which makes heat exchange with other apparatuses mounted on the equipment. The pump apparatus

1

comprises a housing

3

formed with a refrigerant flow passage

2

, a rotating shaft

4

provided in the housing

3

, a bearing structure

6

having slide bearing members

5

which rotatably support the rotating shaft

4

, a motor

9

having a rotor

7

and a stator

8

, and a pump body

10

connected to the rotating shaft

4

. For the sake of global environmental conservation, iron freon gas is not used for the refrigerant, but liquid ammonia is used.

Assembled to the housing

3

are a cylindrical-shaped member

11

shown in

FIGS. 5 and 6

, a pump chamber forming member

12

shown in

FIGS. 7

,

8

,

9

and

10

, a suction port forming member

13

shown in

FIGS. 11

,

12

and

13

, and a discharge port forming member

14

shown in

FIGS. 14 and 15

. The cylindrical-shaped member

11

is thin-walled and cylindrical-shaped, and both axial ends

15

and

16

thereof are formed with a plurality of, for example, circumferentially three, through holes

17

,

18

, respectively.

The pump chamber forming member

12

is formed at its one axial end

19

with an axially opened fitting recess

20

, in which a pump chamber

22

having a cylindrical-shaped, inner peripheral surface is formed to be contiguous to the other axial end of the fitting recess

20

. The fitting recess

20

is coaxial with an axis L

12

of the pump chamber forming member

12

, and the pump chamber

22

is of a smaller diameter than that of the fitting recess

20

to be formed offset from the axis L

12

of the pump chamber forming member

12

.

Also, the pump chamber forming member

12

is formed at the other axial end

21

with an axially opened bearing recess

23

, which is coaxial with the axis L

12

of the pump chamber forming member

12

, and with a shaft insertion hole

24

, which passes through the pump chamber forming member

12

along the axis L

12

to provide communication between the pump chamber

22

and the bearing recess

23

. Further, the pump chamber forming member

12

is formed with an inside pump port

25

, which is contiguous to the pump chamber

22

on a side of the other axial end

21

, and an inside pump passage

26

, which is offset from the axis L

12

of the pump chamber forming member

12

to pass in parallel to the axis L

12

. The inside pump port

25

is formed in an arc extending about an axis of the pump chamber

22

, that is, an axis L

22

of an inner peripheral surface facing the pump chamber

22

, the inside pump passage

26

being axially opened at the other axial end

21

of the pump chamber forming member

12

.

Such pump chamber forming member

12

is inserted into the cylindrical-shaped member

11

from a side of the other axial end

21

, and mounted to the one axial end

15

of the cylindrical-shaped member

11

by inserting bolts

28

through the respective through holes

17

and screwing the same to the pump chamber forming member

12

with the use of threaded holes

27

. In this state, an O-ring

31

is provided between the cylindrical-shaped member

11

and the pump chamber forming member

12

to be fitted into an annular groove

30

, which is formed in an outer peripheral portion at the other axial end

21

of the pump chamber forming member

12

, thus attaining sealing.

Formed in the suction port forming member

13

are an axially opened suction port

33

, which is disposed at a one axial end

32

to be offset from an axis L

13

of the suction port forming member

13

, and a suction passage

34

contiguous to the suction port

33

to extend axially in parallel to the axis L

13

of the suction port forming member

13

, the suction passage

34

being axially opened at the other axial end

35

of the suction port forming member

13

. Also, formed in the suction port forming member

13

are an axially opened bearing recess

36

, which is disposed at the other axial end

35

to be coaxial with the axis L

13

of the suction port forming member

13

, and a shaft insertion recess

37

contiguous to the bearing recess

36

to extend near a center in the axial direction along the axis L

13

of the suction port forming member

13

.

Such suction port forming member

13

is inserted into the cylindrical-shaped member

11

from a side of the other axial end

35

, and mounted to the other axial end

16

of the cylindrical-shaped member

11

by inserting bolts

38

through the respective through holes

18

and screwing the same to the suction port forming member

13

with the use of threaded holes

39

. In this state, an O-ring

41

is provided between the cylindrical-shaped member

11

and the suction port forming member

13

to be fitted into an annular groove

40

, which is formed in an outer peripheral portion at the other axial end

35

of the suction port forming member

13

, thus attaining sealing.

Formed in the discharge port forming member

14

is an axially opened discharge port

43

, which is disposed at the one axial end

42

thereof to be offset from an axis L

14

of the discharge port forming member

14

. Further, formed in the discharge port forming member

14

is an outside pump port

45

, which is disposed at the other axial end

44

thereof to be offset from the axis L

14

of the discharge port forming member

14

. The outside pump port

45

is disposed in a position corresponding to the discharge port

43

with respect to in a circumferential direction to extend circumferentially arcuately. Further, formed in the discharge port forming member

14

is a discharge passage

46

, which is offset from the axis L

14

of the discharge port forming member

14

to extend through the discharge port forming member

14

in parallel to the axis L

14

.

Such discharge port forming member

14

has the other axial end

44

fitted into the fitting recess

20

of the pump chamber forming member

12

to plug the pump chamber

22

in the axial direction. The pump chamber forming member

12

is provided at its one axial end

19

with a flange

47

, which extends radially outward and is formed with a plurality of (for example, four) threaded holes

46

, and the discharge port forming member

14

is provided at its one axial end

42

with a flange

49

, which extends radially outward and is formed with a plurality of (for example, four) through holes

48

. Bolts

50

inserted through the respective through holes

48

are screwed into the flange

47

with the use of the threaded holes

46

, whereby the discharge port forming member

14

is mounted to the pump chamber forming member

12

with its other axial end

44

fitted into the fitting recess

20

. In this state, an O-ring

52

is provided between the pump chamber forming member

12

and the discharge port forming member

14

to be fitted into an annular groove

51

, which is formed in an outer peripheral portion at the other axial end

44

of the discharge port forming member

14

, thus attaining sealing.

In this manner, the housing

3

is constructed, in which state the axis L

11

of the cylindrical-shaped member

11

, the axis L

12

of the pump chamber forming member

12

, the axis L

13

of the suction port forming member

13

, and the axis L

14

of the discharge port forming member

14

are in accord with the axis L

3

of the housing

3

. A rotor chamber

55

is formed in the housing

3

to be disposed between the pump chamber forming member

12

and the suction port forming member

13

, and the suction passage

34

and the inside pump passage

26

are communicated to the rotor chamber

55

. Accordingly, the suction port

33

and the discharge port

43

are formed in the housing

3

, and the flow passage

2

is formed to communicate with these ports

33

,

43

. The flow passage

2

of a fluid refrigerant is formed by connection of at least the suction passage

34

, the rotor chamber

55

, the inside pump passage

26

, the inside pump port

25

, the pump chamber

22

, the outside pump port

45

and the discharge passage

46

in this order. Such housing

3

is composed of, for example, stainless steel.

Provided within such housing

3

is the rotating shaft

4

being a movable member shown in

FIGS. 16 and 17

, the rotating shaft

4

being rotatably supported by the slide bearing members

5

, which are support members shown in

FIGS. 18 and 19

. The rotating shaft

4

is formed of stainless steel to be columnar-shaped, and its one axial end

69

is partially cut away in a circumferential direction to be oval-shaped in cross section to be adapted for latching. In this embodiment, two slide bearing members

5

are provided, each of which is formed of amorphous carbon to be made in the form of a short cylinder.

The respective slide bearing members

5

are press fitted into and fixed to the bearing recess

23

of the pump chamber forming member

12

and the bearing recess

36

of the suction port forming member

13

in such a way that the axis L

5

is in accord with the axis L

3

of the housing

3

. In this manner, the respective slide bearing members

5

are held by and provided in the housing

3

to be exposed to the rotor chamber

55

, which constitutes a part of the flow passage

2

. In a state of being inserted through the respective slide bearing members

5

, the rotating shaft

4

is inserted through the shaft insertion hole

24

of the pump chamber forming member

12

with one axial end thereof disposed in the pump chamber

22

and the other axial end thereof

56

inserted and disposed in the shaft insertion recess

37

.

In this manner, the rotating shaft

4

is rotatably supported about the axis L

3

from radially outward by the slide bearing members

5

with the axis L

4

in accord with the axis L

3

of the housing

3

. Thus the respective slide bearing members

5

are radial bearings for supporting the rotating shaft

4

in a radial direction. When the rotating shaft

4

has an outer diameter of, for example, 2 mm, a radial gap d between the rotating shaft

4

and the respective slide bearing members

5

is at least 0.75 mm and at most 2 mm with an inner diameter of the slide bearing members

5

being selected to be at most 2.015 mm and at least 2.004 mm. Such gap is dimensioned to allow a refrigerant in the rotor chamber

55

to enter thereinto due to the capillary phenomenon. Thus the gap is formed to be extremely small, thus enabling stably stable support of the rotating shaft

4

.

Fitted in the pump chamber

22

as shown in

FIGS. 24 and 25

are an inner gear

60

shown in

FIGS. 20 and 21

, and an outer gear

61

shown in

FIGS. 22 and 23

. The inner gear

60

is formed at an outer periphery thereof with a plurality of (for example, four) teeth

62

. The outer gear

61

is substantially cylindrical-shaped and formed at an inner periphery thereof with teeth

63

, the number of which is more by one than that of the teeth

62

of the inner gear

60

.

As shown in

FIG. 26

, the inner gear

60

is fixed to one end

69

of the rotating shaft

4

in a state in which a spacer

65

in the form of a substantially elliptical cylinder is press fitted onto one end

55

of the rotating shaft

4

and the inner gear is press fitted onto the spacer

65

. Accordingly, the inner gear

60

has its axis L

60

aligned with the axis L

3

of the housing

3

. The outer gear

61

is fitted onto the inner gear

60

in a state of meshing with the inner gear

60

. The outer gear

61

has an outer diameter slightly smaller than an inner periphery of the pump chamber

22

and has its axis L

61

aligned with the axis L

22

of the pump chamber

22

to be eccentric relative to the inner gear

60

.

These inner gear

60

, outer gear

61

and a portion surrounding the pump chamber

22

constitute a displacement pump, concretely a pump body

10

being a trochoidal gear pump. With the pump body

10

, a plurality of pressure chambers are defined between the inner gear

60

and the outer gear

61

, so that when the inner gear

60

is rotated by rotation of the rotating shaft

4

, the outer gear

61

correspondingly rotates to vary volumes of the pressure chambers. The pressure chambers are communicated to the inside pump port

25

in a position where volumes become large, and are made contiguous to the outside pump port

45

in a position where volumes become small.

Also, the inner gear

60

and the outer gear

61

are formed of amorphous carbon. The inner gear

60

also functions as a thrust bearing for axially supporting the rotating shaft

4

.

The rotor

7

fixed to the rotating shaft

4

and formed of a magnet is provided in the rotor chamber

55

, and the stator

8

is provided in a position surrounding the rotor

7

outside the housing

3

. Drive means

9

is constituted by the rotor and the stator. The stator

8

includes a coil, which is electrically energized to impart torque to the rotor

7

due to the magnetic action between it and the rotor

7

, thus rotatingly driving the rotating shaft

4

to rotate the inner gear

60

to drive the pump body

10

. Thereby, the pump body

10

causes a refrigerant to be sucked from the suction port

33

to flow down the flow passage

2

to be discharged from the discharge port

43

.

Amorphous carbon (referred below to as “AC”) is also called glass carbon, and is amorphous carbon to have a property of a low coefficient of friction.

FIGS. 28A and 28B

show results of a test in which a coefficient of friction was measured by sliding, for example a stationary test piece

70

formed of AC shown in

FIG. 27

, on an outer periphery of a rotating test piece formed of high carbon chromium bearing steel (SUJ2) or silicon nitride (Si

3

N

4

). In this manner, members formed of AC exhibit small coefficients of friction even when no lubricant exists between them and other members, and further exhibit extremely small coefficients of friction when a lubricant is present, irrespective of the kind of lubricant.

Also, members formed of AC have a property in that the coefficients of friction are small.

FIGS. 30A and 30B

show results of a test in which depth of severe-mild wear was measured by rotating, pushing and sliding a test shaft

74

, which was formed of stainless steel and had a semi-spherical shaped tip end, on, for example, a stationary test piece

73

formed of AC and shown in FIG.

29

. Also,

FIGS. 32A and 32B

show results of a test, in which severe-mild wear and surface roughness were measured by rotating, pushing and sliding a test piece

75

, which was formed of alumina ceramics, on a test piece composed of AC or several compounds in water as shown in FIG.

31

. As indicated by these test results and a graph in

FIG. 33

, members formed of AC are small in coefficient of friction as compared with other members formed of other materials, and so hard to abrade, and are small in surface roughness even in the case of wearing.

Further, members formed of AC are small in coefficient of thermal expansion as shown in

FIG. 34

, small in bulk density as shown in

FIG. 35

, and high in melting point or temperature thermal deformation to be high in heat resistance as shown FIG.

36

.

Also, Table 1 shows properties of AC and other materials in combination, Table 2 showing properties of AC, Table 3 showing contents of impurities in the slide bearing members

5

formed of AC, inner gear

60

and the outer gear

61

, and Table 4 showing hydrofluoric acid resistance of the slide bearing members

5

formed of AC, inner gear

60

and the outer gear

61

.

TABLE 1

ductility

coefficient

fusing

Young's

(breaking

of thermal

bonding

point or

strength

modulus

strain)

expansion

density

material

structure

strength

Tg (K)

(MPa)

(GPa)

(%)

×10

−6

/° C.

(Mg/m

3

)

ceramics

aggregation

ionic bond

high

large

large

small

small

small to

of

and

800-3500

1000-20000

70-700

10

0

0-10

medium

compound-

covalent

1-5

based

bond

crystal

metal

crystal of

metallic

medium

medium

medium

medium

medium

medium to

simple

bond

400-3400

400-3000

70-400

10

0

-10

2

4-40

large

substance or

2-20

solid

solution

organic

amorphous

covalent

low

small

small

medium

large

small

polymer

substance

bond

350-600

10-100

10 or

10

0

-10

3

10

2

or more

1-2

composed of

less

molecular

chain

amorphous

simple,

covalent

2600

200

30

1

3

1.5

carbon

amorphous

bond

substance

isotropic

crystal

covalent

3600

40-90

10-15

10

0

4.6-6.5

1.7-1.9

high-

aggregation

bond

density

of simple

graphite

substance

TABLE 2

* properties

gas

Coefficient

heat

Charpy

ash

bulk

trans-

bending

tensil

tensil

elastic

Resist-

of thermal

con-

impact

con-

density

porosity

mittance

strength

strength

elon-

modulus

ibility

expansion

ductivity

Shore

strength

tent

g/cm

3

%

cm

2

/sec

MPa

MPa

gation %

GPa

μΩ · cm

×10

−6

/K

W/m · K

hardness

kg · cm/cm

2

ppm

1.46-1.60

0.6-0.9

2.4 × 10

−12

120

(40)

(1.1)

30

4400-

3.0

5-8

127-130

(2.1-3.6)

20

4500

TABLE 3

* analytical value of ash content (impurities)

impurities

total ash

Al

Ca

Cr

Ba

Fe

Co

Mn

Sr

Ni

V

Si

content

concentration

ND

1.5

<0.1

<0.1

2.5

0.1

ND

<0.1

1.4

<0.1

2.7

20

(ppm)

TABLE 4

hydrofluoric acid resistance

impurities

Al

Ca

Cr

Cu

Fe

K

Mg

Na

Ni

Pb

Si

concentration

0.14

<1

<0.1

<0.2

<0.5

<1

<0.05

0.3

<0.05

<0.2

<1000

(ppm)

As apparent from the above-mentioned respective test results and the respective Tables 1 to 4, AC possesses properties such as lightness, low coefficient of thermal expansion, high rigidity, high heat resistance, gas non-permeability, high hardness, abrasion resistance, low coefficient of friction, compact homogeneous structure, chemical resistance and carbon powder non-falling or the like, and is much suitable as a material for members, which slide relative to other members. That is, AC can be much suitably used as the above-mentioned slide bearing member.

FIG. 37

is a graph showing the relationship between discharge pressure and flow rate of the pump apparatus

1

making use of water at 5.5° C.,

FIG. 38

being a graph showing the relationship between discharge pressure and flow rate of the pump apparatus

1

making use of ethyl ether, and

FIG. 39

being a graph showing the relationship between discharge pressure and flow rate of the pump apparatus

1

making use of liquid ammonia at 8° C. Also,

FIG. 40

is a graph showing the relationship between discharge pressure and flow rate of the pump apparatus

1

making use of ethyl ether at 10° C.,

FIG. 41

being a graph showing the relationship between input power to the drive means and flow rate of the pump apparatus

1

making use of ethyl ether at 10° C.,

FIG. 42

being a graph showing the relationship between number of revolutions and flow rate of the pump apparatus

1

making use of ethyl ether at 10° C. In addition,

FIGS. 40

to

42

show results in the case of using ethyl ether easy to handle while the inventors of this application have confirmed that similar results can be obtained in the case of using liquid ammonia.

Table 5 shows results of the performance test of the pump apparatus

1

making use of ethyl ether at temperature of 10° C., Table 6 showing results of the performance test of the pump apparatus

1

making use of ethyl ether at temperature of 20° C., Table 7 showing results of the performance test of the pump apparatus

1

making use of ethyl ether at temperature of 40° C., Table 8 showing results of the performance test of the pump apparatus

1

making use of ethyl ether at temperature of 60° C., Tables 9 and 10 showing results of the performance test of the pump apparatus

1

making use of ethyl ether at temperature of 60° C., and Tables 11 to 13 showing results of the performance test of the pump apparatus

1

making use of liquid ammonia at 8° C.

TABLE 5

number of

input side

discharge side

differential

current

input

revolution

pressure

pressure

pressure

flow rate

A

W

msec

rpm

V

gf/cm

2

V

gf/cm

2

gf/cm

2

V

cc/min

kg/h

0.188

3.01

3.74

4011

−0.196

−284

−0.075

−109

175

3.89

233

10.12

0.209

3.34

4.02

3731

−0.193

−279

−0.020

−29

250

3.30

198

8.60

0.218

3.49

4.14

3623

−0.193

−280

0.003

5

285

2.85

171

7.42

0.235

3.76

4.38

3425

−0.190

−274

0.044

64

338

2.13

128

5.54

0.279

4.46

5.14

2918

−0.180

−261

0.118

171

431

0.00

0

0.00

TABLE 6

number of

input side

discharge side

differential

current

input

revolutions

pressure

pressure

pressure

flow rate

A

W

msec

rpm

V

gf/cm

2

V

gf/cm

2

gf/cm

2

V

cc/min

kg/h

0.167

2.67

3.46

4335

−0.096

−137

0.044

63

201

4.19

251

10.76

0.196

3.14

3.84

3906

−0.086

−123

0.148

211

334

3.08

185

7.91

0.211

3.38

4.08

3676

−0.079

−112

0.209

298

410

2.07

124

5.32

0.226

3.62

4.38

3425

−0.073

−104

0.255

363

467

1.02

61

2.61

0.243

3.89

4.56

3289

−0.071

−102

0.289

413

515

0.00

0

0.00

TABLE 7

number of

input side

discharge side

differential

current

input

revolutions

pressure

pressure

pressure

flow rate

A

W

msec

rpm

V

gf/cm

2

V

gf/cm

2

gf/cm

2

V

cc/min

kg/h

0.197

3.15

3.88

3866

0.246

342

0.381

530

188

4.40

264

11.02

0.206

3.30

4.06

3695

0.236

328

0.421

585

257

3.68

221

9.20

0.215

3.44

4.16

3606

0.243

338

0.455

632

294

2.99

179

7.48

0.225

3.60

4.38

3425

0.246

342

0.486

676

334

2.29

137

5.73

0.238

3.81

4.56

3289

0.255

354

0.530

737

383

1.39

84

3.48

0.262

4.19

5.00

3000

0.256

356

0.576

801

445

0.00

0

0.00

TABLE 8

number of

input side

discharge side

differential

current

input

revolution

pressure

pressure

pressure

flow rate

A

W

msec

Rpm

V

gf/cm

2

V

gf/cm

2

gf/cm

2

V

cc/min

kg/h

0.206

3.30

4.08

3676

0.789

1065

0.943

1273

208

4.23

254

10.27

0.215

3.44

4.22

3555

0.785

1059

0.969

1308

249

3.60

216

8.74

0.220

3.52

4.34

3456

0.787

1062

0.996

1345

283

3.06

184

7.44

0.236

3.78

4.60

3261

0.804

1085

1.056

1425

340

2.03

122

4.93

0.248

3.97

4.84

3099

0.820

1107

1.102

1488

381

1.13

68

2.74

0.269

4.30

5.20

2885

0.783

1057

1.096

1480

423

0.00

0

0.00

TABLE 9

number of

input side

discharge side

differential

current

input

revolution

pressure

pressure

pressure

flow rate

A

W

Hz

rpm

V

gf/cm

2

V

gf/cm

2

gf/cm

2

V

cc/min

kg/h

0.215

3.44

59.10

3546

−141

131

272

310

0.229

3.66

55.86

3352

−90

380

470

250

0.240

3.84

53.47

3208

−59

544

603

200

0.253

4.05

50.76

3046

−36

699

735

150

0.266

4.26

48.07

2884

−22

826

848

100

0.282

4.51

44.64

2678

−8

966

974

50

0.295

4.72

42.73

2564

−3

0

TABLE 10

number of

input side

discharge side

differential

current

input

revolutions

pressure

pressure

pressure

flow rate

A

W

Hz

rpm

V

gf/cm

2

V

gf/cm

2

gf/cm

2

V

cc/min

kg/h

0.286

4.58

39.06

2344

−162

157

319

330

0.300

4.80

37.03

2222

−134

330

464

300

0.325

5.20

33.33

2000

−92

587

679

250

0.351

5.62

30.12

1807

−66

828

894

200

0.384

6.14

26.10

1566

−39

150

0.416

6.66

22.72

1363

−22

100

0.459

7.34

18.31

1099

−7

50

0.490

7.84

15.33

920

−2

0

TABLE 11

number of

input side

discharge side

differential

current

input

revolution

pressure

pressure

pressure

flow rate

A

W

Hz

rpm

V

gf/cm

2

V

gf/cm

2

gf/cm

2

V

cc/min

kg/h

0.145

2.32

64.10

3846

2.398

3309

2.569

3545

236

4.52

271

11.22

0.160

2.56

59.17

3550

2.393

3303

2.659

3669

366

3.05

183

7.58

0.193

3.09

56.17

3370

2.417

3335

2.742

3784

449

2.26

136

5.62

0.250

4.00

45.45

2727

2.412

3329

2.818

3889

560

0.18

11

0.44

TABLE 12

number of

input side

discharge side

differential

current

input

revolutions

pressure

pressure

pressure

flow rate

A

W

V

rpm

V

gf/cm

2

V

gf/cm

2

gf/cm

2

V

cc/min

kg/h

0.150

2.40

3.99

3660

2.486

3431

2.630

3629

198

5.24

315

13.03

0.160

2.56

3.85

3531

2.469

3407

2.649

3656

249

4.29

257

10.65

0.170

2.72

3.75

3439

2.464

3400

2.704

3732

332

3.15

189

7.83

TABLE 13

number of

input side

discharge side

differential

current

input

revolutions

pressure

pressure

pressure

flow rate

A

W

Hz

rpm

V

gf/cm

2

V

gf/cm

2

gf/cm

2

V

cc/min

kg/h

0.120

1.92

91.90

5514

2.550

3519

2.620

3616

97

5.00

300

12.42

The pump apparatus

1

makes use of the slide bearing members

5

formed of the above-mentioned AC to support the rotating shaft

4

, and so the above-mentioned construction can realize a pump apparatus of high efficiency involving a small consumption power required for operation as shown in

FIGS. 37

to

42

and Tables 5 to 13.

With the above-mentioned pump apparatus

1

, the drive means

9

drives the rotating shaft

4

to drive the pump body

10

connected to the rotating shaft

4

so that the refrigerant sucked through the suction port

33

can be made to flow down the flow passage

2

to be discharged from the discharge port

43

. The rotating shaft

4

is rotatably supported by the bearing apparatus

6

having the slide bearing members

5

. The slide bearing members

5

are formed of amorphous carbon, which possesses the above-mentioned properties and can support the rotating shaft

4

for smooth rotation. Besides, amorphous carbon possesses high chemical resistance and so is free of damage even in the case of being fitted into the fluid flow passage. Further, the rotating shaft

4

, the slide bearing members

5

and the rotor

7

are fitted into the flow passage

2

. The gap between the rotating shaft

4

and the slide bearing members

5

is formed to be exceedingly small as described above to further stabilize rotation of the rotating shaft

4

.

Such exceedingly small gap allows entering of liquid ammonia as the refrigerant due to the capillary phenomenon. As AC possesses high chemical resistance, it is free of damage even in the case of being fitted into the fluid flow passage. Also, the slide bearing members

5

formed of AC are made irrespective of the kind of a fluid used, and accordingly liquid ammonia can be made use of as a favorable lubricant. Accordingly, the pump apparatus makes it possible to use a refrigerant being fed as a lubricant and to achieve smooth rotation of the rotating shaft. Further, since the bearing structure

6

can be formed by means of slide bearing members, it can be made simple and undergoes less failure.

Also, AC is small in coefficient of friction to suppress the generation of heat produced upon rotation of the rotating shaft

4

and can prevent thermal expansion of the rotating shaft

4

and the slide bearing members

5

. Besides, even if frictional heat is generated, stable rotation could be maintained because AC is small in coefficient of thermal expansion and the gap, between the rotating shaft

4

and the slide bearing members

5

is not varied in dimension. Further, AC is small in coefficient of friction, so that with the above-mentioned small gap smooth rotation is achieved even for fluids of high viscosity such as liquid ammonia. Also, owing to small wear, even over long term use, the fluid is prevented from being contaminated with abrasion powder and the above-mentioned gap is prevented from being varied in dimension, so that smooth and stable rotation can be realized over a long term without maintenance. Accordingly, the pump apparatus can be preferably mounted on equipment used in outer space outside the stratosphere to enhance durability.

Also, provision of such rotating members in the housing

3

makes the sealing properties favorable and simplifies the construction therefor, thus enabling making the pump apparatus

1

small in size. Also, it is possible to cool the rotating shaft

4

, the slide bearing members

5

and the rotor

7

to keep a stable performance of the pump. Further, the cylindrical-shaped member

11

is thin-walled to provide a cooling effect of the stator

8

surrounding the rotor chamber

55

. Besides, the drive means

9

including the slide bearing members

5

and the rotor

7

is located upstream of the pump body

10

in a flow direction of the refrigerant, so that the slide bearing members

5

and the rotor

7

can be cooled prior to fluid compression by the pump body

10

and so a stable and favorable cooling effect is obtained. In this manner, such excellent pump apparatus

1

can be realized.

Also, the pump body

10

is formed of amorphous carbon, which is hardly subjected to chemical influences by the fluid, and maintains the function of the pump body over a long term, thus realizing a favorable pump apparatus

1

. Further, formation of the pump body

10

of amorphous carbon can have the pump body

10

fulfilling the function of thrust bearings and bearing the thrust load of the rotating shaft

4

. Therefore, the load on the slide bearing members

5

can be reduced. In this manner, the load is imposed on the pump body

10

to make it possible to reduce the slide bearing members

5

in size and enhance durability of the pump apparatus.

The above-mentioned embodiment is only exemplary of the invention and can be modified within the scope of the invention. For example, the slide bearing members

5

may be one in number or three or more. Also, the fluid may be other on than liquid ammonia.

Also, the support apparatus and the pump apparatus may be used in other equipment, such as medical equipment, than equipment used in outer space outside the stratosphere.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and the range of equivalency of the claims are therefore intended to be embraced therein.

Number	Name	Date	Kind
4342491	Jamison et al.	Aug 1982	A
4731302	Weissmantel et al.	Mar 1988	A
5366298	Toshimitsu et al.	Nov 1994	A
5747631	Sasaki et al.	May 1998	A
5765392	Baur	Jun 1998	A
6114791	Ito et al.	Sep 2000	A
6502991	Knepper et al.	Jan 2003	B2

Number	Date	Country
2314130	May 1994	CA
0600468	Jun 1994	EP
0752538	Jan 1997	EP
470014	Aug 1937	GB
1259672	Jan 1972	GB
1279827	Jun 1972	GB
05-296248	Nov 1993	JP
6-193637	Jul 1994	JP
7-53260	Feb 1995	JP
7-259749	Oct 1995	JP
9-203381	Aug 1997	JP
10-112949	Apr 1998	JP
11-292526	Oct 1999	JP
2000-213533	Aug 2000	JP
2001-032840	Feb 2001	JP

Support apparatus for movable member and pump apparatus

Information

Patent Number

Date Filed

Date Issued

Inventors

Original Assignees

Examiners

Agents

CPC

US Classifications

Field of Search

US

International Classifications

Abstract

Description

Claims

Priority Claims (1)

US Referenced Citations (7)

Foreign Referenced Citations (15)