Hollow swivel actuator

Patent metadata

Field	Value
Publication number	US-12379015-B2
Application number	US-202318867338-A
Country	US
Kind code	B2
Filing date	Apr 7, 2023
Priority date	May 31, 2022
Publication date	Aug 5, 2025
Grant date	Aug 5, 2025

Abstract

Provided is a hollow swivel actuator including: a lower housing in which a driving motor is arranged; and an upper housing in which three gear trains and three pinion gear units for reduction are arranged at intervals of 120 degrees. A rotor worm gear for transferring an output of the driving motor is coupled through gear engagement to a ring gear integrally formed on a rotational table to transfer reduced rotational power therebetween. The hollow swivel actuator obtains a great reduction ratio by: primary reduction between the rotor worm gear of the driving motor and first to third worm wheels of the first to third gear trains; secondary reduction between first to third worm gears and fourth to sixth worm wheels of the first to third pinion gear units; and tertiary reduction between the ring gear and the first to third pinion gears, thereby achieving a large torque increase.

First claim

What is claimed is:

1. A hollow swivel actuator comprising:
a lower housing having a hollow cylindrical portion protruding upward at a center thereof;
an upper housing stacked and assembled on an upper portion of the lower housing and having a through hole formed in a central portion thereof in which the hollow cylindrical portion protrudes upward through the through hole;
a driving motor arranged on a bottom surface of the lower housing and having a cylindrical rotor worm gear integrally formed on an outer circumference of a cylindrical rotor support extending upward from the rotor;
first to third gear trains arranged and coupled at intervals of 120 degrees on the outer circumference of the rotor worm gear protruding through the upper housing, and having first to third worm wheels formed to be gear-coupled to the rotor worm gear on one side of each of first to third power transmission shafts to achieve primary reduction and first to third worm gears formed on the other side of each of the first to third power transmission shafts;
first to third pinion gear units having fourth to sixth worm wheels formed on bottom ends thereof so as to be gear-coupled to the first to third worm gears to achieve secondary reduction, and first to third pinion gears integrally formed on top ends thereof; and
a rotational table in which the first to third pinion gears of the first to third pinion gear units are gear-coupled to a ring gear integrally formed inside a side portion thereof to achieve a tertiary reduction.

2. The hollow swivel actuator of claim 1 , wherein both ends of each of the first to third power transmission shafts are rotatably supported by a plurality of bearings, and a plurality of set screws are installed in a bearing housing in which the plurality of bearings are embedded to suppress the occurrence of left and right displacements of the first to third power transmission shafts.

3. The hollow swivel actuator of claim 2 , further comprising a plurality of set screw adjustment through holes formed on a wall of the upper housing and used to fix the first to third power transmission shafts by pushing the plurality of set screws from the outside to one side.

4. The hollow swivel actuator of claim 1 , wherein a first reduction ratio of the primary reduction, a second reduction ratio of the secondary reduction, and a third reduction ratio of the tertiary reduction are sequentially set less toward a rear end.

5. The hollow swivel actuator of claim 1 , wherein the driving motor comprises:
a rotor having a cylindrical rotor support having a cup shape at a lower end thereof, and rotatably coupled to an outer circumference of the hollow cylindrical portion;
a stator which is arranged on the outer side of the rotor with an air gap, generates a rotating magnetic field, and is arranged on the bottom of the housing to rotate the rotor;
first and second bearings arranged between the cup-shaped lower end of the rotor support and a lower end of the hollow cylindrical portion to rotatably support the rotor, and stacked in series; and
a bearing support press-coupled to the outer circumference of the hollow cylindrical portion to press the second bearing.

6. The hollow swivel actuator of claim 1 , further comprising:
first and second bearings arranged between a lower end of the cylindrical rotor support and a lower end of the hollow cylindrical portion of the lower housing to rotatably support the rotor and stacked in series; and
a third bearing rotatably supporting the rotational table on an outer circumference of a top end of the hollow cylindrical portion.

7. The hollow swivel actuator of claim 6 , further comprising a bearing support press-coupled to the outer circumference of the cylindrical rotor support and arranged between the second bearing and the third bearing to press the second bearing.

8. The hollow swivel actuator of claim 1 , further comprising first to third support shafts having lower ends fixedly installed through the bottom of the upper housing and rotatably supporting the first to third pinion gear units, respectively.

9. The hollow swivel actuator of claim 8 , wherein a virtual circle formed by the first to third support shafts forms the same concentric circle as the rotational table, the first to third support shafts are arranged at intervals of 120 degrees on the virtual circle, and the first to third pinion gears are gear-coupled to the ring gear at three points at intervals of 120 degrees.

10. The hollow swivel actuator of claim 1 , wherein the rotor support, the cylindrical rotor worm gear, the first virtual circle formed by the first to third worm wheels, and a second virtual circle formed by the first to third support shafts, and the rotational table are arranged based on the same concentric circle.

Assignees

• Amotech Co Ltd

Inventors

• Kim Byung Soo
• Shin Jong Hwa

Classifications

• H02K7/1166

  comprising worm and worm-wheel (structural association with bearings specially adapted for worm gear drives H02K7/081) · CPC title

• H02K7/1163

  where at least two gears have non-parallel axes without having orbital motion · CPC title

• H02K7/116

  with gears · CPC title

• F16H57/12

  Arrangements for adjusting or for taking-up backlash not provided for elsewhere · CPC title

• F16H57/039

  Gearboxes for accommodating worm gears · CPC title