# US 5,347,187 A · Miniature electric motor

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- Number: US 5,347,187 A
- Document ID: US5347187A
- Status: Granted
- Kind: A
- Application number: 07/913,637
- Filed: 1992-07-16
- Granted: 1994-09-13
- Earliest claimed: 1991-08-29
- Assignees: Matsushita Electric Industrial Co., Ltd.
- Inventors: Toshiaki Tsuzaki; Noriyoshi Naito
- Web page: https://patentgrep.com/patent/US5347187A

## CPC

- H02K 5/1675: {radially supporting the rotary shaft at only one end of the rotor (H02K5/1677 takes precedence)}
- H02K 21/22: with magnets rotating around the armatures, e.g. flywheel magnetos
- H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53})

## Abstract

In a miniature electric motor a hollow cylindrical socket (2) is formed by deep drawing process on a roof plate of a frame (1), and in this socket (2) a bearing housing (4) is tightly fit projecting outwardly and inwardly from its roof plane, and at least one bearing metal (3) is further tightly fitted therein in a manner to project from both ends of the bearing housing (4). By utilizing the draw-worked socket (2) for tightly holding the bearing metal (3), the accuracy of axis or circularity of the bearing hole is assured.

## Claims

### Claim 1

A miniature electric motor comprising:
a rotor having a rotor shaft;
a stator; and
a single-piece frame top of generally cylindrical bowl shape for supporting said stator and said rotor;
a frame bottom secured to said frame top forming a frame enclosing said stator and said rotor;
said single-piece frame top forming a hollow cylindrical socket for holding a bearing structure projecting both outwardly and inwardly from a roof plane of said frame; and
said bearing structure comprising at least one bearing metal, said bearing structure being tightly fit in said socket of said frame and projecting both outwardly and inwardly from said roof plane of said frame, said bearing structure having a first and a second rotating sliding contact point to said rotor shaft;
wherein a predetermined clearance is formed in the direction of an axis of said rotor shaft between said first rotating sliding contact point and said second rotating sliding contact point.

### Claim 2 (depends on 1)

The miniature electric motor in accordance with claim 1, wherein said bearing structure further comprises a bearing housing.

### Claim 3 (depends on 1)

The miniature electric motor in accordance with claim 1, wherein said bearing structure projects only outwardly from said roof plate of said frame.

### Claim 4 (depends on 1, 2)

The miniature electric motor in accordance with claim 1 or 2, wherein positions along said axis of said rotor shaft where said bearing structure contacts said socket, and where said first rotating sliding contact point contacts said rotor shaft, are staggered with each other along the direction of said axis of said rotor shaft.

### Claim 5 (depends on 1)

The miniature electric motor in accordance with claim 1, wherein positions along said axis of said rotor shaft where said bearing structure contacts said socket, and where said first and said second rotating sliding contact points contact said rotor shaft, are staggered with each other along the direction of said axis of said rotor shaft.