Speed reduction device for motor

Patent metadata

Field	Value
Publication number	US-11984793-B2
Application number	US-202318117710-A
Country	US
Kind code	B2
Filing date	Mar 6, 2023
Priority date	Mar 25, 2022
Publication date	May 14, 2024
Grant date	May 14, 2024

Abstract

Disclosed is a speed reduction device for a vehicle motor. The speed reduction device includes an output gear connected to an output shaft of the motor, a transmission gear engaged with the output gear, a cam formed to be integrated with the transmission gear, a cycloid inner gear, a pair of wedges compressed against the inner peripheral surface of a through hole of the cycloid inner gear by elastic restoring force of a spring and configured to closely contact the cam, a ring gear partially engaged with the cycloid inner gear when the cycloid inner gear is eccentrically rotated, an end plate, and a final output gear configured to finally output rotational force of the cycloid inner gear, thereby preventing backlash between gears during rotational driving of the motor and reliably preventing movement of a seat after swivel adjustment is completed.

First claim

What is claimed is:

1. A speed reduction device for a motor, comprising:
a transmission gear engaged with an output gear of a motor and disposed in a speed-reducing housing;
a cam including a pair of rotational force transmission protrusions formed to protrude from an outer surface thereof, the cam being integrally mounted on an outer surface of the transmission gear;
a ring gear formed on an outer surface of the housing;
a cycloid inner gear including a through hole formed therein and a plurality of rotational force transmission pins formed thereon, the cycloid inner gear being engaged with the ring gear;
a pair of wedges disposed in close contact with an inner peripheral surface of the through hole so as to respectively contact the pair of rotational force transmission protrusions entering the through hole;
a spring configured to compress the pair of wedges against the inner peripheral surface of the through hole with elastic restoring force; and
an end plate including a plurality of restraining holes formed therein and configured to allow the plurality of rotational force transmission pins to be respectively inserted thereinto so as to enable power transmission.

2. The speed reduction device of claim 1 , wherein the output gear of the motor is embodied as a worm gear connected to an output shaft of the motor and located in the speed-reducing housing, and the transmission gear is embodied as a worm wheel gear engaged with the worm gear.

3. The speed reduction device of claim 1 , wherein the through hole is formed in a center portion of the cycloid inner gear and the plurality of rotational force transmission pins are formed on an outer surface of the cycloid inner gear, and the cycloid inner gear is partially engaged with the ring gear while being eccentric with respect to the transmission gear.

4. The speed reduction device of claim 1 , wherein the spring includes a broken-shape ring portion supported by the transmission gear and includes elastic support ends respectively bent in axial directions from opposite ends of the ring portion, the elastic support ends respectively compressing the pair of wedges against the inner peripheral surface of the through hole of the cycloid inner gear with the elastic restoring force.

5. The speed reduction device of claim 4 , wherein the transmission gear includes a support jaw formed on an outer surface thereof, wherein the support jaw allows the ring portion of the spring to be wound therearound and supported thereby.

6. The speed reduction device of claim 4 , wherein the wedges include restraining grooves respectively formed at opposite one ends thereof and configured to face each other so that the elastic support ends are respectively inserted into the restraining grooves and restrained therein, and each of the wedges gradually becomes thinner toward the other end thereof.

7. The speed reduction device of claim 1 , further comprising a rotational support shaft including an inner end configured to pass through the through hole of the cycloid inner gear and a rotational center portion of the transmission gear and the cam, the inner end being rotatably engaged with the housing, the rotational support shaft further including an outer end configured to eccentrically pass through the through hole of the cycloid inner gear and formed to extend toward the end plate.

8. The speed reduction device of claim 7 , wherein the transmission gear, the cam, and the end plate are coaxially arranged by the rotational support shaft, and the cycloid inner gear is engaged with the ring gear while the pair of wedges is in contact with and supported by the pair of rotational force transmission protrusions of the cam so as to be arranged eccentrically with respect to the transmission gear, the cam, and the end plate.

9. The speed reduction device of claim 1 , wherein the plurality of rotational force transmission pins are integrally formed on an outer surface of the cycloid inner gear and spaced apart by circumferentially equal distances around the cycloid inner gear, and the plurality of restraining holes are formed to penetrate the end plate and are spaced apart by circumferentially equal distances around the end plate.

10. The speed reduction device of claim 9 , wherein the end plate includes a final output gear mounted on an outer surface thereof, and wherein center portions of the end plate and the final output gear are rotatably inserted into and supported by a rotational support shaft.

11. The speed reduction device of claim 9 , wherein an inner diameter of each of the restraining holes is formed to be larger than a cross-sectional diameter of each of the rotational force transmission pins of the cycloid inner gear.

12. The speed reduction device of claim 11 , wherein, when the rotational force transmission pins of the cycloid inner gear are respectively inserted into the restraining holes of the end plate, some of the rotational force transmission pins are respectively in close contact with the inner peripheral surfaces of corresponding ones of the restraining holes in a direction of restraining clockwise rotation of the end plate, and rest of the rotational force transmission pins are respectively in close contact with the inner peripheral surfaces of corresponding ones of the restraining holes in a direction of restraining counterclockwise rotation of the end plate.

13. The speed reduction device of claim 10 , further comprising a housing cover including an output hole formed therein and configured to allow the final output gear to protrude to an outside of the housing cover, the housing cover being fastened to the speed-reducing housing with the ring gear interposed therebetween.

Assignees

• Hyundai Transys Inc
• Mars Co Ltd

Inventors

• Park Hee Jun
• Kim Byung Mo
• Jang Woo Kyo
• Jang Chang Hee
• Shin Jun Ho

Classifications

• H02K7/1166 Primary

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

• B60N2/02246

  Electric motors therefor · CPC title

• B60N2/02253

  characterised by the transmission between the electric motor and the seat or seat parts · CPC title

• F16H1/32 Primary

  in which the central axis of the gearing lies inside the periphery of an orbital gear · CPC title

• F16H2001/325

  comprising a carrier with pins guiding at least one orbital gear with circular holes · CPC title