Speed reducer-equipped motor unit

Patent metadata

Field	Value
Publication number	US-12072017-B2
Application number	US-202218551402-A
Country	US
Kind code	B2
Filing date	Nov 22, 2022
Priority date	Nov 22, 2022
Publication date	Aug 27, 2024
Grant date	Aug 27, 2024

Abstract

A motor unit for transmitting a driving force of a motor driven by a battery to an opening and closing mechanism through a worm gear and a worm wheel includes lubricating grease. The grease includes a solid additive that increases a friction coefficient between the worm gear and the worm wheel as its addition amount increases. The addition amount is not less than a first threshold and is not more than a second threshold. The first threshold is an addition amount for realizing a friction coefficient at which transmission efficiency from the worm wheel to the worm gear becomes 0 [%]. The second threshold is an addition amount for realizing a friction coefficient at which a starting voltage of the motor to move the opening and closing mechanism in an opening direction becomes a minimum guaranteed voltage of the battery after the opening and closing mechanism is restrained fully closed.

First claim

The invention claimed is:

1. A speed reducer-equipped motor unit that includes a motor driven by electric power supplied from a battery and transmits a driving force of the motor to an opening and closing mechanism through a worm gear and a worm wheel,
the speed reducer-equipped motor unit comprising grease that lubricates the worm gear and the worm wheel,
the grease including base oil serving as a base material of the grease, a thickener that is dispersed in the base oil and forms a three-dimensional structure, a solid additive that is dispersed in the base oil and increases a friction coefficient between the worm gear and the worm wheel as an addition amount thereof increases,
an amount of the addition amount ranges from a first threshold value to a second threshold value,
the first threshold value being the amount of the addition amount for realizing the friction coefficient at which transmission efficiency from the worm wheel to the worm gear becomes 0 [%],
the second threshold value being the amount of the addition amount for realizing the friction coefficient at which a starting voltage of the motor, the starting voltage being required to move the opening and closing mechanism in a direction of opening, becomes a minimum guaranteed voltage of the battery after the opening and closing mechanism is restrained to be fully closed in a specific environment and,
wherein the specific environment is an environment in which an output voltage of the battery is higher than a rated voltage of the battery.

2. The speed reducer-equipped motor unit according to claim 1 , wherein the solid additive is an acrylic resin powder.

3. The speed reducer-equipped motor unit according to claim 1 , wherein
the minimum guaranteed voltage is a voltage that is 60 [%] of a rated voltage of the battery.

4. The speed reducer-equipped motor unit according to claim 1 , wherein
the opening and closing mechanism is a power window.

Assignees

• Mabuchi Motor Co

Inventors

• Yamamoto Kazuyuki

Classifications

• F16H57/0498

  Worm gearings · CPC title

• F16H19/02

  for interconverting rotary {or oscillating} motion and reciprocating motion · CPC title

• E05Y2900/55

  Windows · CPC title

• E05Y2201/71

  Toothed gearing · CPC title

• E05F15/603

  using rotary electromotors · CPC title