Rotary compressor including a plurality of recessed portions for retaining lubricating oil

Patent metadata

Field	Value
Publication number	US-11959480-B2
Application number	US-202017793293-A
Country	US
Kind code	B2
Filing date	Sep 30, 2020
Priority date	Jan 29, 2020
Publication date	Apr 16, 2024
Grant date	Apr 16, 2024

Abstract

A compression unit of a rotary compressor includes a cylinder, an upper end plate that closes the upper side of the cylinder, a lower end plate that closes the lower side of the cylinder, and a piston that is fitted to a rotating shaft, revolves along an inner peripheral surface of the cylinder, and forms a cylinder chamber in the cylinder. At least one of an end face of the piston in the axial direction of the rotating shaft, a sliding surface of the upper end plate that slides with the end face of the piston, and a sliding surface of the lower end plate that slides with the end face of the piston, has formed therein an oil-film retention region having an array of a plurality of recessed portions that retain lubricating oil.

First claim

The invention claimed is:

1. A rotary compressor comprising:
a compressor housing that is provided with a refrigerant discharge portion and a refrigerant suction portion;
a compression unit that is arranged in the compressor housing and configured to compress a refrigerant, which is sucked from the suction portion, and discharge the refrigerant from the discharge portion; and
a motor that is arranged in the compressor housing and configured to drive the compression unit, wherein
the compression unit includes an annular cylinder; an upper end plate that closes an upper side of the cylinder; a lower end plate that closes a lower side of the cylinder; a rotating shaft that is rotated by the motor; a piston that is fitted to the rotating shaft and is configured to revolve along an inner peripheral surface of the cylinder and form a cylinder chamber in the cylinder; and a vane that projects from a vane groove provided on the cylinder into the cylinder chamber and brought into contact with the piston so as to section the cylinder chamber into a suction chamber and a compression chamber,
at least one end face of both end faces of the piston in an axial direction of the rotating shaft has formed therein an oil-film retention region having an array of a plurality of recessed portions that are configured to retain lubricating oil, and
each of the plurality of recessed portions is not connected to an inner peripheral surface and an outer peripheral surface of the piston and formed in a linear shape having a bend portion, and arranged in a radial direction of the piston with a projecting end of the bend portion oriented in a circumferential direction of the piston.

2. The rotary compressor according to claim 1 , wherein, in the axial direction of the rotating shaft, a gap between the at least one end face of the piston and at least one end plate of the upper end plate and the lower end plate is greater than 0, and is 1/1000 or less of a height of the piston in the axial direction, and
in the oil-film retention region, an area ratio, which is occupied by a total of opening areas of the recessed portions to an area of the at least one end face, is 40% or less, and a depth of each recessed portion to the at least one end face is 3 μm or less.

3. The rotary compressor according to claim 1 , wherein the plurality of recessed portions arranged in the at least one end face of the piston in the radial direction of the piston are formed at intervals in the circumferential direction of the piston around an entire circumference of the piston.

4. The rotary compressor according to claim 1 , wherein the plurality of recessed portions arranged in the radial direction of the piston include a recessed portion with both ends in a radial direction connected to an end of an adjacent recessed portion.

Assignees

• Fujitsu General Ltd

Inventors

• Katayama Hiroki
• Furukawa Motonobu

Classifications

• F04C18/3564 Primary

  the surfaces of the inner and outer member, forming the working space, being surfaces of revolution · CPC title

• F04C2/3448

  with axially movable vanes · CPC title

• F04C29/02

  Lubrication (of machines or engines in general F01M); Lubricant separation (separation in general B01D) · CPC title

• F04C29/028

  Means for improving or restricting lubricant flow · CPC title

• F04C23/008

  Hermetic pumps · CPC title