Patent Description:
One type of compressor is generally referred to as a scroll compressor. Scroll compressors generally include a pair of scroll members which orbit relative to each other to compress air or a refrigerant. A typical scroll compressor includes a first, stationary scroll member having a base and a generally spiral wrap extending from the base and a second, orbiting scroll member having a base and a generally spiral wrap extending from the base. The spiral wraps of the first and second orbiting scroll members are interleaved, creating a series of compression chambers. The second, orbiting scroll member is driven to orbit the first, stationary scroll member by a rotating shaft. Some scroll compressors employ an eccentric pin on the rotating shaft that drives the second, orbiting scroll member.

As prior art there may be mentioned: <CIT>, which discloses a scroll compression device that prevents scattering of lubrication oil to a discharge pipe side comprising a cup which is opened at the lower portion thereof and prevents scattering of lubrication oil disposed on the lower surface of the main frame, and an annular insulator having a double wall structure which surrounds windings disposed on the upper surface of a stator, wherein the peripheral wall of the cup is hung between the double walls of the insulator; <CIT>, which discloses a lubricating construction of a scroll compressor that includes a seal member provided between an orbiting scroll and a main frame to isolate a back pressure chamber from bearing portions to thereby keep the bearing portions substantially under a discharge pressure, a first oil feed passage extending from a lubricating oil portion under the discharge pressure to a space, disposed adjacent to an end of a crank portion of the crankshaft, through the crankshaft, a second oil feed passage extending from the above space to be opened to sliding portions of end plates of the orbiting and stationary scrolls through the end plate of the orbiting scroll, and communicating with the back pressure chamber, and a third oil feed passage extending from midway the first oil feed passage to be opened to an outer peripheral surface of the crankshaft, and serving to supply a lubricating oil to a main bearing portion by the use of a centrifugal pumping action produced by rotation of the crankshaft, wherein the second oil feed passage has midway a throttle portion of a reduced flow passage area; <CIT>, which discloses a scroll compressor in which a back-pressure chamber is divided into a first space under roughly discharge pressure at its central section and a second space under medium pressure at its outer periphery by a sealing member, wherein lubricating oil is led to the first space, and the second space is communicated with a compressed space in the cause of compression via a small hole, wherein a drain oil passage opened to the first space is provided, and communicates with a drain oil pipe for leading the lubrication oil to its bottom section inside a sealed container; <CIT>, which discloses a recess which is formed in the bottom part of a receiving part and in which oil accumulates after lubrication of a sliding part of an engagement part, and an oil supply passage, which feeds the oil in the recess to sliding parts of the compressor, are formed in the housing of a scroll compressor; and <CIT>, which discloses an oil supply structure of a scroll compressor, wherein the oil supply structure is provided to prevent a slender hole of an oil supply screw from being clogged with sludge, the oil supply screw being provided between a backpressure space, which is defined between an orbiting scroll and a main frame, and a space which is defined between a fixed scroll and the main frame, and adapted to supply oil from the backpressure space into the space, wherein the oil supply screw includes an orifice having a center hole longitudinally perforated through the center of an upper portion of a screw body of the oil supply screw and a slender hole continuously perforated below the center hole to have the same axis as that of the center hole, and a sludge discharger having a non-flat-plane configuration and formed at a lower entrance end of the screw body.

The present invention is defined by the attached independent claim, to which reference should now be made. Additional embodiments of the present invention are defined by the dependent claims appended thereto. This disclosure relates generally to scroll compressors. More specifically, the disclosure relates to a bearing housing drain in a scroll compressor for controlling lubrication of a thrust bearing in the scroll compressor.

In some embodiments, the scroll compressor can be used in a refrigeration system to compress a heat transfer fluid.

In some embodiments, the scroll compressor can be used in a system other than a refrigeration system. In such embodiments, the scroll compressor can, for example, be used to compress air or gases other than a heat transfer fluid (e.g., natural gas, etc.).

The scroll compressor includes a housing drain cavity having a bearing housing drain. The bearing housing drain is disposed at an angle relative to a horizontal axis. In some embodiments, the angle can be up to at or about <NUM> degrees.

A lubricant can be forced from the housing drain cavity through the bearing housing drain and returned to a lubricant sump when a compressor is in operation. The lubricant can drain toward the housing drain cavity when the compressor is not in operation. Draining the lubricant toward the housing drain cavity can, in some embodiments, form a pool of lubricant which can be used upon compressor startup. In some embodiments, the pool of lubricant can provide lubrication to an orbiting scroll and thrust bearing of the compressor at a relatively quicker rate than if no pool of lubricant were formed. In some embodiments, this can increase a lifetime of the compressor. In some embodiments this can also reduce failure of components of the compressor due to insufficient lubrication.

A compressor is disclosed. The compressor includes the features according to independent claim <NUM>.

A heat transfer circuit is disclosed according to claim <NUM>.

A method according to claim <NUM> is also disclosed.

References are made to the accompanying drawings that form a part of this disclosure and which illustrate embodiments in which the systems and methods described in this specification can be practiced.

This disclosure relates generally to scroll compressors. More specifically, the disclosure relates to a bearing housing drain in a scroll compressor for controlling lubrication of a thrust bearing in the scroll compressor.

A bearing housing drain is generally included in a housing drain cavity of a scroll compressor. The bearing housing drain can prevent lubricant from filling the housing drain cavity, which can cause unwanted drag, which can result in efficiency loss. A vertical position of an inlet location of the bearing housing drain, a diameter of the bearing housing drain, and an angle at which the bearing housing drain is formed are useful design considerations for the bearing housing drain. For example, the vertical position of the inlet location can affect the ability and amount of lubricant pumped by the orbiting scroll bearing hub that pumps lubricant to the orbiting scroll thrust surface. The angle of the bearing housing drain can, for example, help control a level of lubricant pooled in the housing drain cavity at the time of compressor startup. Controlling the level of lubricant pooled in the housing drain cavity can create a lubricant source that is particularly useful at the time of compressor startup. The lubricant pooled in the housing drain cavity can advantageously reduce an amount of time of compressor operation before lubricant can be pumped to, for example, the orbiting scroll thrust surface, as compared to a scroll compressor without a pool of lubricant in the housing drain cavity in which the lubricant is pumped from the lubricant sump at the time of startup. In some embodiments, this can increase a lifetime of the compressor and/or reduce compressor failures. The angle of the bearing housing drain can also be selected to control an amount of lubricant within the housing drain cavity during a period of operation of the compressor.

<FIG> is a schematic diagram of a heat transfer circuit <NUM>. The heat transfer circuit <NUM> generally includes a compressor <NUM>, a condenser <NUM>, an expansion device <NUM>, and an evaporator <NUM>. The compressor <NUM> is a scroll compressor such as the scroll compressor shown and described in accordance with <FIG> below. The heat transfer circuit <NUM> is exemplary and can be modified to include additional components. For example, in some embodiments the heat transfer circuit <NUM> can include an economizer heat exchanger, one or more flow control devices, a receiver tank, a dryer, a suction-liquid heat exchanger, or the like.

The heat transfer circuit <NUM> can generally be applied in a variety of systems used to control an environmental condition (e.g., temperature, humidity, air quality, or the like) in a space (generally referred to as a conditioned space). Examples of systems include, but are not limited to, heating, ventilation, and air conditioning (HVAC) systems, transport refrigeration systems, or the like.

The components of the heat transfer circuit <NUM> are fluidly connected. The heat transfer circuit <NUM> can be specifically configured to be a cooling system (e.g., an air conditioning system) capable of operating in a cooling mode. Alternatively, the heat transfer circuit <NUM> can be specifically configured to be a heat pump system which can operate in both a cooling mode and a heating/defrost mode.

Heat transfer circuit <NUM> operates according to generally known principles. The heat transfer circuit <NUM> can be configured to heat or cool heat transfer fluid or medium (e.g., a liquid such as, but not limited to, water or the like), in which case the heat transfer circuit <NUM> may be generally representative of a liquid chiller system. The heat transfer circuit <NUM> can alternatively be configured to heat or cool a heat transfer medium or fluid (e.g., a gas such as, but not limited to, air or the like), in which case the heat transfer circuit <NUM> may be generally representative of an air conditioner or heat pump.

In operation, the compressor <NUM> compresses a heat transfer fluid (e.g., refrigerant or the like) from a relatively lower pressure gas to a relatively higher-pressure gas. The relatively higher-pressure and higher temperature gas is discharged from the compressor <NUM> and flows through the condenser <NUM>. In accordance with generally known principles, the heat transfer fluid flows through the condenser <NUM> and rejects heat to a heat transfer fluid or medium (e.g., water, air, etc.), thereby cooling the heat transfer fluid. The cooled heat transfer fluid, which is now in a liquid form, flows to the expansion device <NUM>. The expansion device <NUM> reduces the pressure of the heat transfer fluid. As a result, a portion of the heat transfer fluid is converted to a gaseous form. The heat transfer fluid, which is now in a mixed liquid and gaseous form flows to the evaporator <NUM>. The heat transfer fluid flows through the evaporator <NUM> and absorbs heat from a heat transfer medium (e.g., water, air, etc.), heating the heat transfer fluid, and converting it to a gaseous form. The gaseous heat transfer fluid then returns to the compressor <NUM>. The above-described process continues while the heat transfer circuit is operating, for example, in a cooling mode (e.g., while the compressor <NUM> is enabled).

<FIG> illustrates the compressor <NUM> having a bearing housing drain <NUM>. The compressor <NUM> can be used in the heat transfer circuit <NUM> of <FIG>. It is to be appreciated that the compressor <NUM> can also be used for purposes other than in a heat transfer circuit. For example, the scroll compressor <NUM> can be used to compress air or gases other than a heat transfer fluid (e.g., natural gas, etc.). It is to be appreciated that the scroll compressor <NUM> may include one or more additional features. For example, the scroll compressor <NUM> can include one or more filters for filtering the lubricant to prevent contaminants (e.g., metal or the like) from being introduced to the features being lubricated.

The illustrated compressor <NUM> is a single-stage scroll compressor. More specifically, the illustrated compressor <NUM> is a single-stage vertical scroll compressor. It is to be appreciated that the principles described in this specification are not intended to be limited to single-stage scroll compressors and that they can be applied to multi-stage scroll compressors having two or more stages.

The compressor <NUM> is illustrated in cross-sectional side view. The scroll compressor <NUM> includes a hermetically sealed housing <NUM>. The housing <NUM> includes an upper portion 22A, a lower portion 22B, a middle portion 22C, and an intermediate portion 22D. It will be appreciated that the compressor <NUM> may not include the intermediate portion 22D (sometimes alternatively referred to as the intermediate cap 22D). The compressor <NUM> includes a suction inlet <NUM> and a discharge outlet <NUM>.

The compressor <NUM> includes an orbiting scroll <NUM> and a non-orbiting scroll <NUM>. The non-orbiting scroll <NUM> can alternatively be referred to as, for example, the stationary scroll <NUM>, the fixed scroll <NUM>, or the like. The non-orbiting scroll <NUM> is aligned in meshing engagement with the orbiting scroll <NUM> by means of an Oldham coupling <NUM>.

The compressor <NUM> includes a driveshaft <NUM>. The driveshaft <NUM> can alternatively be referred to as the crankshaft <NUM>. The driveshaft <NUM> can be rotatably driven by, for example, an electric motor <NUM>. The electric motor <NUM> can generally include a stator <NUM> and a rotor <NUM>. The driveshaft <NUM> is fixed to the rotor <NUM> such that the driveshaft <NUM> rotates along with the rotation of the rotor <NUM>. The electric motor <NUM>, stator <NUM>, and rotor <NUM> operate according to generally known principles. The driveshaft <NUM> can, for example, be fixed to the rotor <NUM> via an interference fit or the like.

The driveshaft <NUM> includes an opening <NUM>. The opening <NUM> can alternatively be referred to as the lubricant passage <NUM>, according to some embodiments. The opening <NUM> is fluidly connected to the lubricant sump <NUM> and an upper main housing <NUM>. In operation, lubricant can be provided from the lubricant sump <NUM> to the components (e.g., thrust bearing <NUM>, orbiting scroll <NUM>, etc.) of the upper main housing <NUM> via the opening <NUM>. To enable the flow of lubricant, a lubricant pump <NUM> extends into the lubricant sump <NUM>. The lubricant pump <NUM> is fixed to a lower end of the driveshaft <NUM>. As a result, the lubricant pump <NUM> can pump lubricant from the lubricant sump <NUM> via centrifugal force when the driveshaft <NUM> rotates. The lubricant pump <NUM> operates according to generally known principles.

The main upper housing <NUM> includes a housing drain cavity <NUM>. The housing drain cavity <NUM> builds up lubricant received from the opening <NUM>. The built-up lubricant provides lubrication to the thrust bearing <NUM>, orbiting scroll <NUM>, and the like in the main upper housing <NUM>. The thrust bearing <NUM> generally can receive lubricant which is pushed by the orbiting scroll hub <NUM> against the walls of the housing drain cavity <NUM> until it reaches the thrust bearing <NUM>.

To prevent too much lubricant from building up in the housing drain cavity <NUM>, the housing drain cavity <NUM> includes the bearing housing drain <NUM>. The bearing housing drain <NUM> is fluidly connected to the housing drain cavity <NUM>. The bearing housing drain <NUM> can prevent an excess amount of lubricant from building up in the housing drain cavity <NUM>, which may cause excessive drag.

An inlet end 20A of the bearing housing drain <NUM> receives the lubricant from the housing drain cavity <NUM>. In line with the claimed invention, the inlet end 20A of the bearing housing drain <NUM> is disposed a distance y from a bottom surface of the thrust bearing <NUM>, which is vertically lower than a lower end of the orbiting scroll hub <NUM>. It will be appreciated that the distance y can be varied based on, for example, a geometry of the orbiting scroll hub <NUM> (see <FIG> for additional discussion of the geometry of the orbiting scroll hub <NUM>). In some embodiments of the disclosure not according to the claimed invention, the inlet end 20A of the bearing housing drain <NUM> that receives the lubricant from the housing drain cavity <NUM> is disposed at about the same vertical location as the lower end of the orbiting scroll hub <NUM>. The placement enables lubricant to drain from the housing drain cavity <NUM>. A higher elevation for the inlet end 20A may cause lubricant to be pumped into the bearing housing drain <NUM> (and returned to the lubricant sump <NUM>) instead of being provided to the thrust bearing <NUM>. An outlet end 20B of the bearing housing drain <NUM> that is located relatively farther from the housing drain cavity <NUM> allows lubricant to flow toward the lubricant sump <NUM>.

The bearing housing drain <NUM> is inclined with respect to a horizontal axis x at an angle α. The angle α can be e.g. up to at or about <NUM> degrees. The angle α can be selected to control an amount of lubricant that drains (via gravity) into the housing drain cavity <NUM> versus an amount of lubricant that drains (via gravity) into the lubricant sump <NUM>. For example, a relatively shallow angle α allows lubricant to drain toward the lubricant sump <NUM>. A relatively higher angle α reduces an amount of lubricant exiting the housing drain cavity <NUM>. A relatively higher angle α allows lubricant to drain toward the housing drain cavity <NUM>. In some embodiments, a higher angle α can increase reliability. Too high of an angle α can cause unwanted drag. The selection of the angle α also generally controls a steady-state lubricant volume in the housing drain cavity <NUM> during operation of the compressor <NUM>.

Angling the bearing housing drain <NUM> at an angle α can provide lubricant to the thrust bearing <NUM> more quickly than if the lubricant is pumped from the lubricant sump <NUM> on compressor startup. For example, the bearing housing drain <NUM> being disposed at an angle α can enable a pool of lubricant to be maintained in the housing drain cavity <NUM>, which can be pumped to the thrust bearing <NUM> on compressor startup. In some embodiments this can, for example, ensure proper lubrication of the components of the compressor <NUM> upon startup. Providing increased lubrication of the components of the compressor <NUM> can, for example, increase the lifetime of the compressor <NUM>. Accordingly, the angle α can be selected to control a depth of lubricant pooled in the housing drain cavity <NUM> upon compressor shutdown that can be provided to the thrust bearing <NUM>, or the like, upon compressor startup before the lubricant can be provided from the lubricant sump <NUM> via the lubricant pump <NUM>.

The design of the bearing housing drain <NUM> (e.g., a diameter d, the distance y from the lower surface of the thrust bearing <NUM>, and the angle α) can be optimized to provide an optimal combination of lubricant delivery to bearings of the compressor <NUM>, power draw of the compressor <NUM> during operation, and lubricant delivery time at startup of the compressor <NUM>. In some embodiments, the optimal combination of the diameter d, the distance y, and the angle α can be selected for a particular compressor size and operating parameter.

<FIG> illustrate various geometries for an outer surface <NUM> of the orbiting scroll hub <NUM> (<FIG>). <FIG> illustrates the orbiting scroll hub <NUM> having an outer surface that is cylindrical, according to some embodiments. <FIG> illustrates the orbiting scroll hub <NUM> having an outer surface <NUM> that is tapered (e.g., chamfered), according to an example not within the scope of the claimed invention. <FIG> illustrates the orbiting scroll hub <NUM> having an outer surface <NUM> that is stepped, according to another example not within the scope of the claimed invention.

The bearing housing drain <NUM> is generally disposed in fluid communication with the housing drain cavity <NUM>. An inlet of the bearing housing drain <NUM> is disposed at a location proximate to the housing drain cavity <NUM> such that lubricant from the housing drain cavity <NUM> can flow into the bearing housing drain <NUM> when the compressor <NUM> is in operation. Further, with such placement, lubricant can drain from the bearing housing drain <NUM> toward the housing drain cavity <NUM> when the compressor is not in operation. An outlet of the bearing housing drain <NUM> is generally disposed at a location which is relatively vertically higher than the inlet, the relative vertical height being based on the angle α of the bearing housing drain <NUM>.

In the illustrated embodiments and examples, the bearing housing drain <NUM> is disposed a distance y1, y2, y3 from lower surface of the thrust bearing <NUM> (<FIG>). The distances y1 - y3 can vary due to the geometry of the outer surface <NUM> of the orbiting scroll hub <NUM>. Generally, y1 is greater than y2 and y3 and y2 may be greater than y3. The bearing housing drain <NUM> is generally at a distance w1, w2, w3 (in a left-right direction of <FIG>) from the outer surface <NUM> of the orbiting scroll hub <NUM>. In some embodiments and examples, the distances w1 - w3 can be the same. In some embodiments and examples, the distances w1 - w3 can be different. It will be appreciated that the distances w1 - w3 may depend on, for example, the compressor <NUM> (<FIG>) in which the bearing housing drain <NUM> is implemented. It will further be appreciated that a wall of the housing drain cavity <NUM> (<FIG>) can be chamfered or stepped in place of the orbiting scroll hub <NUM>.

The terminology used in this specification is intended to describe particular embodiments and is not intended to be limiting. The terms "a," "an," and "the" include the plural forms as well, unless clearly indicated otherwise. The terms "comprises" and/or "comprising," when used in this specification, indicate the presence of the stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, and/or components.

Claim 1:
A compressor (<NUM>), comprising:
a compressor housing (<NUM>);
a non-orbiting scroll member (<NUM>) and an orbiting scroll member (<NUM>);
an orbiting scroll hub (<NUM>) having an upper end and a lower end, the lower end being disposed at a vertical elevation that is lower than the upper end;
a thrust bearing (<NUM>);
a lubricant sump (<NUM>);
a housing drain cavity (<NUM>) disposed within the compressor housing (<NUM>) and configured to receive lubricant from the lubricant sump (<NUM>) and to deliver the lubricant to the thrust bearing (<NUM>), whereby, in use, lubricant is pushed by the orbiting scroll hub (<NUM>) against walls of the housing drain cavity (<NUM>) until it reaches the thrust bearing (<NUM>); and
a bearing housing drain (<NUM>) fluidly connected to the housing drain cavity (<NUM>) and the lubricant sump (<NUM>), wherein the bearing housing drain (<NUM>) receives a lubricant flow from the housing drain cavity (<NUM>) at an inlet end (20A), and a portion of the lubricant flow is directed from the housing drain cavity (<NUM>) through the bearing housing drain (<NUM>) to an outlet end (20B),
characterized in that the outlet end (20B) of the bearing housing drain (<NUM>) is disposed at a location which is relatively vertically higher than the inlet end (20A) of the bearing housing drain (<NUM>), the inlet end (20A) is relatively vertically lower than the lower end of the orbiting scroll hub (<NUM>), and the outlet end (20B) is relatively vertically higher than the lower end of the orbiting scroll hub (<NUM>).