# US 9,751,644 B2 · Three-dimensional rigid ball driving system

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- Number: US 9,751,644 B2
- Document ID: US9751644B2
- Status: Granted
- Kind: B2
- Application number: 14/414,852
- Filed: 2013-07-24
- Published: 2015-06-18
- Granted: 2017-09-05
- Earliest claimed: 2012-07-25
- Assignees: Korea Aerospace Research Institute
- Applicants: Korea Aerospace Research Institute
- Inventors: Dae-Kwan Kim; Hyungjoo Yoon; Wooyong Kang; Yong Bok Kim; Hong-Taek Choi
- Web page: https://patentgrep.com/patent/US9751644B2

## CPC

- B64G 1/285: {using momentum wheels}
- B64G 1/244: {Spacecraft control systems}
- B64G 1/283: {using reaction wheels}
- B64G 1/32: using earth's magnetic field
- G05D 1/0808: {specially adapted for aircraft}
- H02K 5/173: using bearings with rolling contact, e.g. ball bearings
- H02K 5/1737: {radially supporting the rotor around a fixed spindle; radially supporting the rotor directly}
- H02K 7/088: {radially supporting the rotor directly}
- H02K 16/04: Machines with one rotor and two stators
- H02K 17/16: having rotors with internally short-circuited windings, e.g. cage rotors
- H02K 41/025: Asynchronous motors
- H02K 2201/18: Machines moving with multiple degrees of freedom
- B64G: COSMONAUTICS; VEHICLES OR EQUIPMENT THEREFOR
- G05D: SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
- H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53})

## Abstract

Provided is a three-dimensional rigid ball driving system including: a support frame having a polyhedral shape; a rigid ball positioned at the center of an inner portion of the support frame; a plurality of ball bearings installed at corners of inner sides of the support frame, respectively, and contacting a surface of the rigid ball; and a plurality of electromagnets disposed around the ball bearings and generating magnetic fields to rotate the rigid ball; and a controller controlling the electromagnets to control a rotation direction and a rotation speed of the rigid ball.

## Claims

### Claim 1

A three-dimensional rigid ball driving system comprising:
a support frame (10) having a polyhedral shape;
a rigid ball (20) positioned at the center of an inner portion of the support frame (10);
a plurality of ball bearings (30) installed at corners of inner sides of the support frame (10), respectively, and contacting a surface of the rigid ball (20);
a plurality of electromagnets (40) disposed around the ball bearings (30) and generating magnetic fields to rotate the rigid ball (20); and
a controller (50) controlling the electromagnets (40) to control a rotation direction and a rotation speed of the rigid ball (20),
wherein the ball bearings (30) include balls (31), bearing racers (32) installed in the support frame (10) and having grooves (32A) having the balls (31) seated therein and having a hemispherical shape, and bearing cages (33) coupled to upper portions of the bearing racers (32) and having guide grooves (33A) formed therein and having a hemispherical shape,
the balls (31) being installed so as to be confined in grooves formed by allowing the grooves (32A) of the bearing racers (32) and the guide grooves (33A) of the bearing cages (33) to meet each other.

### Claim 2 (depends on 1)

The three-dimensional rigid ball driving system of claim 1, wherein centers of the balls (31) are positioned at points defined by following Equation 3:
X
=
±
R
+
r
(
3
)
,
Y
=
±
R
+
r
(
3
)
,
Z
=
±
R
+
r
(
3
)
[
Equation
⁢
⁢
3
]
where X, Y, and Z are coordinate values of points at which the centers of the balls (31) of the ball bearings (30) are positioned, R is a radius of the rigid ball (20), and r is a radius of the ball (31) of the ball bearing (30).

### Claim 3 (depends on 1)

The three-dimensional rigid ball driving system of claim 1, wherein the ball bearing (30) and the support frame (10) have a vibration damping member installed therebetween.

### Claim 4 (depends on 1)

The three-dimensional rigid ball driving system of claim 1, wherein a cross section of the support frame in a length direction has a ‘’ shape.

### Claim 5

A three-dimensional rigid ball driving system comprising:
a support frame (10) having a polyhedral shape;
a rigid ball (20) positioned at the center of an inner portion of the support frame (10);
a plurality of ball bearings (30) installed at corners of inner sides of the support frame (10), respectively, and contacting a surface of the rigid ball (20);
a plurality of electromagnets (40) disposed around the ball bearings (30) and generating magnetic fields to rotate the rigid ball (20); and
a controller (50) controlling the electromagnets (40) to control a rotation direction and a rotation speed of the rigid ball (20),
wherein a cross section of the support frame in a length direction has a ‘’ shape.