# US 2013/0156618 A1 · Electric pump

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- Number: US 2013/0156618 A1
- Document ID: US20130156618A1
- Status: Published application
- Kind: A1
- Application number: 13/712,007
- Filed: 2012-12-12
- Published: 2013-06-20
- Earliest claimed: 2011-12-16
- Assignees: Aisan Kogyo Kabushiki Kaisha
- Inventors: Takahiro Nakamura
- Web page: https://patentgrep.com/patent/US20130156618A1

## CPC

- F04D 13/06: the pump being electrically driven
- F04D 13/0633: {Details of the bearings}
- F04D: NON-POSITIVE-DISPLACEMENT PUMPS (engine fuel-injection pumps F02M; ion pumps H01J41/12; electrodynamic pumps H02K44/02)

## Abstract

In an electric pump, a vortex chamber may be formed by a clearance between an outer circumferential surface of an impeller and an inner circumferential surface of a casing. A low rigidity part may be provided to a supporting portion or a shaft, or to both of them. The low rigidity part may be formed such that while the electric pump operates, a center point of the shaft in a top view of the shaft moves along a specific line which is parallel to a tangent line of the outer circumferential surface of the impeller at the specific position and passes through the center point of the shaft while the electric pump does not operate, or moves to one of two areas divided by the specific line. The one of the two areas may he opposite to the other of the two areas that includes the specific position.

## Claims

### Claim 1

An electric pump comprising:
a casing configured to form a motor chamber and a pump chamber;
a shaft of which lower edge side is configured to be supported by a supporting portion disposed on the casing;
a rotor configured to rotate around the shaft;
an impeller configured to be fixed on an upper side of the rotor and be contained rotatably in the pump chamber;
a stator configured to be disposed on an outer circumferential side of the rotor in the motor chamber; and
a vortex chamber configured to be formed by a clearance between an outer circumferential surface of the impeller and an inner circumferential surface of the casing in the pump chamber, wherein
liquid flows in the vortex chamber,
the clearance is the narrowest at a specific position in a circumferential direction of the impeller,
a low rigidity part is provided to the supporting portion or the shaft, or to each of the supporting portion and the shaft, the low rigidity part having lower rigidity than other part of the supporting portion or the shaft to which the low rigidity part is provided, and
the low rigidity part is formed such that while the electric pump operates, a center point of the shaft in a top view of the shaft moves along a specific line, or moves to one of two areas divided by the specific line, the specific line being parallel to a tangent line of the outer circumferential surface of the impeller at the specific position and passing through the center point of the shaft while the electric pomp does not operate, and the one of the two areas being opposite to the other of the two areas that includes the specific position.

### Claim 2 (depends on 1)

The electric pump as in claim 1, wherein
the low rigidity part is included in the shaft,
the low rigidity part is formed on the lower edge side of the shaft, and
the other part of the shaft is formed on the upper edge side of the shaft.

### Claim 3 (depends on 2)

The electric pump as in claim 2, wherein
a cross-sectional area of the low rigidity part of the shaft in a direction vertical to an axis direction of the shaft is smaller than that of the other part of the shaft in the direction.

### Claim 4 (depends on 2)

The electric pump as in claim 2, wherein
the low rigidity part comprises an elastic member formed of a material having an elastic coefficient smaller than that of the other part of the shaft.

### Claim 5 (depends on 1)

The electric pump as in claim 1 wherein
the low rigidity part is included in the supporting portion, and
the low rigidity part is disposed at a part of the supporting portion.