# US 5,344,678 A · Shaft sleeve made of ceramics

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- Number: US 5,344,678 A
- Document ID: US5344678A
- Status: Granted
- Kind: A
- Application number: 07/811,071
- Filed: 1991-12-20
- Granted: 1994-09-06
- Earliest claimed: 1990-12-25
- Assignees: Ebara Corporation
- Inventors: Ken-ichi Kajiwara; Kikuichi Mori
- Web page: https://patentgrep.com/patent/US5344678A

## CPC

- F04D 29/0465: {Ceramic bearing designs}
- F04D 1/063: {of the vertically split casing type}
- F04D 29/4266: {made of sheet metal}
- Y10T 428/131: Glass, ceramic, or sintered, fused, fired, or calcined metal oxide or metal carbide containing [e.g., porcelain, brick, cement, etc.]
- Y10T 428/1317: Multilayer [continuous layer]
- Y10T 428/1321: Polymer or resin containing [i.e., natural or synthetic]
- Y10T 428/1386: Natural or synthetic rubber or rubber-like compound containing
- Y10T 428/1393: Multilayer [continuous layer]
- Y10T 428/31826: Of natural rubber
- F04D: NON-POSITIVE-DISPLACEMENT PUMPS (engine fuel-injection pumps F02M; ion pumps H01J41/12; electrodynamic pumps H02K44/02)
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A shaft sleeve is made of ceramics and provided in confrontation with a stationary sliding member in a sliding bearing or plain bearing. The shaft sleeve made of ceramics comprises a cylindrical body made of ceramics and having a circular outer surface and a circular inner surface, and an elastic member molded on the inner surface of the cylindrical body and being formed with an inner opening having a shape corresponding to the cross section of a shaft. The shaft sleeve is usable under high temperature conditions and with liquids containing much slurry such as, for example, as a shaft sleeve of a pump.

## Claims

### Claim 1

A shaft sleeve for mounting about a shaft for rotation therewith and for mounting inside an annular bearing for rotation relative thereto, said shaft sleeve comprising:
a ceramic cylindrical body having a cylindrical outer surface and a cylindrical inner surface;
a unitary annular elastic member having a cylindrical outer surface fixedly mounted against said cylindrical inner surface of said ceramic cylindrical body, and an inner surface having a cross-sectional shape corresponding to a cross-sectional shape of an outer periphery of the shaft; and
wherein said elastic member constitutes a means for absorbing shock, for transmitting drive from the shaft to said cylindrical body when said shaft sleeve is mounted on the shaft, and for absorbing differences in dimensional variation between said ceramic cylindrical body and the shaft caused by differences in thermal expansion coefficients thereof when said shaft sleeve is mounted on the shaft.

### Claim 2 (depends on 1)

A shaft sleeve as recited in claim 1, wherein said elastic member is formed of rubber.

### Claim 3 (depends on 1)

A centrifugal pump as recited in claim 1, wherein said elastic member has a thickness in a range of 1 percent to 10 percent of a thickness of said cylindrical body.

### Claim 4 (depends on 1)

A shaft sleeve as recited in claim 1, wherein said inner surface of said elastic member has at least one spline-receiving axially extending groove formed therein.

### Claim 5 (depends on 1)

A shaft sleeve as recited in claim 1, wherein said inner surface of said elastic member has a polygonally-shaped cross section.

### Claim 6 (depends on 1)

A shaft sleeve as recited in claim 1, wherein said inner surface of said elastic member has a cross-sectional shape which defines therewithin an oblong opening.

### Claim 7

A centrifugal pump comprising:
a pump casing;
a shaft rotatably provided in said pump casing body;
an impeller supported by said shaft;
a shaft sleeve mounted about said shaft for rotation therewith;
wherein said shaft sleeve includes a ceramic cylindrical body having a cylindrical outer surface and a cylindrical inner surface, and a unitary annular elastic member having a cylindrical outer surface fixedly mounted against said cylindrical inner surface of said ceramic cylindrical body, said elastic member further including an inner surface having a cross-sectional shape corresponding to a cross-sectional shape of an outer periphery of said shaft; and
wherein said elastic member constitutes a means for absorbing shock, for transmitting drive from said shaft to said cylindrical body when said shaft sleeve is mounted on said shaft, and for absorbing differences in dimensional variation between said ceramic cylindrical body and said shaft caused by differences in thermal expansion coefficients thereof when said shaft sleeve is mounted on said shaft.

### Claim 8 (depends on 7)

A centrifugal pump as recited in claim 7, wherein said elastic member is formed of rubber.

### Claim 9 (depends on 7)

A centrifugal pump as recited in claim 7, wherein said elastic member has a thickness in a range of 1 percent to 10 percent of a thickness of said cylindrical body.

### Claim 10 (depends on 7)

A centrifugal pump as recited in claim 7, wherein said inner surface of said elastic member has at least one spline-receiving axially extending groove formed therein.

### Claim 11 (depends on 7)

A centrifugal pump as recited in claim 7, wherein said inner surface of said elastic member has a polygonally-shaped cross section.

### Claim 12 (depends on 7)

A centrifugal pump as recited in claim 7, wherein said inner surface of said elastic member has a cross-sectional shape which defines therewithin an oblong opening.