Gear assembly, reduction gear and cleaning robot

Patent metadata

Field	Value
Publication number	US-10844946-B2
Application number	US-201816039374-A
Country	US
Kind code	B2
Filing date	Jul 19, 2018
Priority date	Jul 26, 2017
Publication date	Nov 24, 2020
Grant date	Nov 24, 2020

Abstract

A gear assembly includes an upper cover and a lower cover, a stator fixed to the lower cover, a rotor opposite to the stator and including a rotary shaft and magnet, a main gear fixed to the rotary shaft and rotating along with the rotary shaft, and a helical gear engaged with the main gear, the main gear and the helical gear being both received in the cover member, the upper cover including a boss portion with a recess receiving a tip of the rotary shaft. The rotor is axially movable and when the rotary shaft stops rotating, the tip of the rotary shaft is in the recess of the boss portion, and when the rotary shaft rotates, the helical gear applies a force on the main gear, and the tip of the rotary shaft is disengaged from the recess of the boss portion.

First claim

What is claimed is:

1. A gear assembly, comprising:
a cover structure including an upper cover and a lower cover;
a stator fixed to the lower cover;
a rotor opposite to the stator and including a rotary shaft and a magnet rotating around a central axis;
a main gear fixed to the rotary shaft and rotating along with the rotary shaft; and
a helical gear engaged with the main gear; wherein
the main gear and the helical gear are both received in the cover structure; the upper cover includes a boss including a recess receiving a tip of the rotary shaft;
the rotor is axially movable;
the helical gear is axially fixed;
when the rotary shaft stops rotating, the tip of the rotary shaft is in the recess of the boss; and
when the rotary shaft rotates, the helical gear applies a force on the main gear, and the tip of the rotary shaft is disengaged from the recess of the boss.

2. The gear assembly according to claim 1 , wherein in a state where the tip of the rotary shaft is disengaged from the recess of the boss, an axial center of the magnet is axially configured in a staggered manner relative to an axial center of the stator.

3. The gear assembly according to claim 1 , wherein
the lower cover includes a recessed portion depressed to the upper cover; and
at least a portion of the rotor together with the stator are received in the recessed portion.

4. The gear assembly according to claim 3 , wherein the gear assembly includes an outer rotor motor including the stator and the rotor, and the magnet is disposed at a radial outer side of the stator.

5. The gear assembly according to claim 1 , wherein an upper surface of the lower cover disposed axially opposite to a lower end of the rotary shaft includes a thrust washer.

Assignees

• Nidec Corp

Inventors

• Zhang Tiecheng
• Zhang Xuechao
• Han Zhenmin

Classifications

• H02K7/125

  magnetically influenced · CPC title

• H02K2213/03

  Machines characterised by numerical values, ranges, mathematical expressions or similar information · CPC title

• H02K7/003

  Couplings; Details of shafts (means for mounting rotors on shafts H02K1/28) · CPC title

• H02K21/22

  with magnets rotating around the armatures, e.g. flywheel magnetos · CPC title

• F16H1/08

  the members having helical, herringbone, or like teeth · CPC title