# US 9,518,573 B2 · Reciprocating compressor with gas bearing

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- Number: US 9,518,573 B2
- Document ID: US9518573B2
- Status: Granted
- Kind: B2
- Application number: 13/602,744
- Filed: 2012-09-04
- Published: 2013-03-07
- Granted: 2016-12-13
- Earliest claimed: 2011-09-06
- Assignees: LG Electronics Inc.
- Applicants: Donghan Kim
- Inventors: Donghan Kim
- Web page: https://patentgrep.com/patent/US9518573B2

## CPC

- F04B 35/045: {using solenoids}
- F04B 39/0005: {adaptations of pistons}
- F04B 39/0027: {Pulsation and noise damping means}
- F04B 39/02: Lubrication (of machines or engines in general F01M)
- F04B 39/0215: {characterised by the use of a special lubricant}
- F04B 39/0223: {characterised by the compressor type (swash-plate compressors F04B27/109)}
- F04B 39/023: {Hermetic compressors}
- F04B 39/0276: {the pump being of the reciprocating piston type, e.g. oscillating, free-piston compressors}
- F04B 39/0292: {Lubrication of pistons or cylinders}
- F04B 39/122: {Cylinder block}
- F04B 39/123: {Fluid connections}
- F04B: POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS (machines for liquids, or pumps, of rotary-piston or oscillating-piston type F04C; non-positive-displacement pumps F04D; pumping of fluid by direct contact of another fluid or by using inertia of fluid to be pumped F04F)

## Abstract

A reciprocating compressor with a gas bearing is configured to support a portion between a cylinder and a piston by the gas bearing and induce a resonating motion of the piston by the use of compression coil springs. Therefore, a proper resonating motion of a vibrating body can be induced by the use of the gas bearing, without using plate springs, and accordingly manufacturing costs and the number of assembly processes can be reduced and the installation direction of the compressor can be freely designed.

## Claims

### Claim 1

A reciprocating compressor with a gas bearing, the reciprocating compressor comprising:
a cylinder having a compression space;
a piston inserted into the compression space, that reciprocates relative to the cylinder;
a discharge valve configured to be attachable to and detachable from a front end surface of the cylinder, to selectively open and close the compression space of the cylinder;
a discharge cover having a discharge space that selectively communicates with the compression space by the discharge valve, and coupled to a front end of the cylinder,
a gas bearing that lubricates a bearing surface of the cylinder and the piston by gas; and
a plurality of resonant springs that supports both sides of the piston in a motion direction, wherein the plurality of resonant springs includes at least one first resonant spring and at least one second resonant spring in the form of compression coil springs, and provided, respectively, on the both sides of the piston, wherein a plurality of at least one of the first resonant spring or the second resonant spring is provided, wherein the plurality of resonant springs is arranged such that lines orthogonal to front end surfaces of at least two of the plurality of resonant springs in a winding direction meet at one point, and wherein the gas bearing includes:
an inlet formed in the cylinder at a distance which is greater than a radius of the discharge valve relative to a center of the discharge valve;
at least one first gas flow path formed in the cylinder in communication with the at least one gas inlet opening, wherein a central longitudinal axis of the at least one first gas flow path extends substantially parallel to a central longitudinal axis of the cylinder;
at least one second gas flow path formed in the cylinder, wherein a central longitudinal axis of the at least one second gas flow path extends substantially perpendicular to the central longitudinal axis of the at least one first gas flow, wherein the gas is provided to the bearing surface through the at least one second gas flow path;
a gas communication opening formed at a center portion of a gas guide provided on an outer circumferential surface of the piston;
a gas guide groove formed on the outer circumferential surface of the piston, wherein the gas guide groove communicates with the gas communication opening, and wherein the gas guide groove has an annular shape and has a larger length in the reciprocating direction of the piston than the gas communication opening so that gas introduced into the gas guide groove is uniformly distributed over the entire bearing surface between the cylinder and the piston; and
a plurality of holes formed at both sides of the gas communication opening in the reciprocating direction of the piston, respectively.

### Claim 2 (depends on 1)

The reciprocating compressor of claim 1, wherein the plurality of the one of the first resonant spring or the second resonant spring is arranged to engage each other such that distal ends of the plurality of first or second resonant springs are wound at a same distance in opposite directions relative to a center of the piston.

### Claim 3 (depends on 1)

The reciprocating compressor of claim 1, wherein the plurality of the one of the first resonant spring or the second resonant spring is arranged to engage each other such that distal ends of the plurality of first or second resonant springs are wound at a same distance in opposite directions along a circumferential direction relative to a center of the piston.

### Claim 4 (depends on 1)

The reciprocating compressor of claim 1, wherein a number of the first resonant spring is equal to a number of the second resonant spring.

### Claim 5 (depends on 1)

The reciprocating compressor of claim 1, wherein the at least one second gas flow path includes an annular gas pocket formed on an inner circumferential surface of the cylinder that communicates with the at least one first gas flow path.

### Claim 6 (depends on 1)

The reciprocating compressor of claim 1, wherein the gas guide has a cylinder shape and includes the plurality of holes at both sides of the gas communication opening, wherein each of the plurality of holes has a significantly smaller surface area than the gas communication opening.

### Claim 7 (depends on 1)

The reciprocating compressor of claim 1, wherein the gas guide is formed as a porous material.