A bearing device for a turbocharger according to one embodiment of the present invention includes: a rotational shaft; a journal bearing device including a compressor-side journal bearing and a turbine-side journal bearing; a bearing housing including a compressor-side bearing supporting portion, a turbine-side bearing supporting portion, and a bearing housing main body; and a lubricant oil guide member extending along a circumference direction of the rotational shaft, at an outer circumference side of at least one of the compressor-side bearing supporting portion and the turbine-side bearing supporting portion. When a virtual line extending vertically downward from a rotational center CL of the rotational shaft is defined as a reference line VL in a state where an oil discharge port is orientated downward, the lubricant oil guide member extends from the reference line VL along the circumference direction toward each of one side and another side of the reference line VL over a predetermined angle θ about the rotational center CL of the rotational shaft.

A bearing device for a turbocharger according to one embodiment of the present invention includes: a rotational shaft; a journal bearing device including a compressor-side journal bearing and a turbine-side journal bearing; a bearing housing including a compressor-side bearing supporting portion, a turbine-side bearing supporting portion, and a bearing housing main body; and a lubricant oil guide member extending along a circumference direction of the rotational shaft, at an outer circumference side of at least one of the compressor-side bearing supporting portion and the turbine-side bearing supporting portion. When a virtual line extending vertically downward from a rotational center CL of the rotational shaft is defined as a reference line VL in a state where an oil discharge port is orientated downward, the lubricant oil guide member extends from the reference line VL along the circumference direction toward each of one side and another side of the reference line VL over a predetermined angle θ about the rotational center CL of the rotational shaft.

On an inner circumferential surface (25a) of a housing (25) opposed to an outer circumferential surface (37a, 37b) of an outer ring, toward a front side in a rotation direction (B) of a rotation shaft (21), a first groove (41H, 41I) is formed as a groove portion for guiding an oil (39) in a direction toward a first oil supply hole (41D, 41E).

On an inner circumferential surface (25a) of a housing (25) opposed to an outer circumferential surface (37a, 37b) of an outer ring, toward a front side in a rotation direction (B) of a rotation shaft (21), a first groove (41H, 41I) is formed as a groove portion for guiding an oil (39) in a direction toward a first oil supply hole (41D, 41E).

A heating, ventilation, air conditioning, and refrigeration (HVACR) system includes a compressor with a gas bearing supplied with compressed gas and a controller. The controller is configured to determine an inlet pressure and outlet pressure of the gas bearing, determine a maximum speed limit based on the inlet pressure and the outlet pressure, and prevent the compressor from operating at a speed that is greater than the maximum speed limit. A method of controlling a compressor includes calculating a maximum speed limit based on an inlet pressure and an outlet pressure of the gas bearing. The method also includes in response to determining that a speed setting is greater than the maximum speed limit, adjusting operation of the compressor such that a speed of the compressor is at or below the maximum speed limit.

A heating, ventilation, air conditioning, and refrigeration (HVACR) system includes a compressor with a gas bearing supplied with compressed gas and a controller. The controller is configured to determine an inlet pressure and outlet pressure of the gas bearing, determine a maximum speed limit based on the inlet pressure and the outlet pressure, and prevent the compressor from operating at a speed that is greater than the maximum speed limit. A method of controlling a compressor includes calculating a maximum speed limit based on an inlet pressure and an outlet pressure of the gas bearing. The method also includes in response to determining that a speed setting is greater than the maximum speed limit, adjusting operation of the compressor such that a speed of the compressor is at or below the maximum speed limit.

A heat transfer circuit includes a compressor, a condenser, an expander, and an evaporator that are fluidly connected together. The compressor includes a housing and a shaft rotatable relative to the housing to compress a working fluid received at a suction inlet, in which the shaft is supported by a gas bearing, and the gas bearing including a bearing housing having a fluid inlet and an outlet. A high pressure gas source is fluidly connected to the fluid inlet of the bearing housing for supplying high pressure fluid to the fluid inlet of the gas bearing such that the gas bearing supports the shaft when the shaft is rotating. A pressure reducer is connected to the outlet of the gas bearing is provided for reducing a vent pressure of the gas bearing.

A heat transfer circuit includes a compressor, a condenser, an expander, and an evaporator that are fluidly connected together. The compressor includes a housing and a shaft rotatable relative to the housing to compress a working fluid received at a suction inlet, in which the shaft is supported by a gas bearing, and the gas bearing including a bearing housing having a fluid inlet and an outlet. A high pressure gas source is fluidly connected to the fluid inlet of the bearing housing for supplying high pressure fluid to the fluid inlet of the gas bearing such that the gas bearing supports the shaft when the shaft is rotating. A pressure reducer is connected to the outlet of the gas bearing is provided for reducing a vent pressure of the gas bearing.

A lubricant supply system is for a compressor that compresses a first working fluid in a heat transfer circuit. The lubricant supply system includes a lubricant tank, a lubricant pathway for supplying lubricant from the lubricant tank to one or more bearings of the compressor, and a lubricant refrigeration system with a lubricant heater and a lubricant cooler. The lubricant heater configured to heat the lubricant discharged from the one or more bearings and the lubricant cooler configured to cool the lubricant flowing through the lubricant pathway. A method of lubricating a compressor includes heating the lubricant, directing the lubricant from a lubricant tank through a lubricant pathway to one or more bearings of the compressor, and cooling the lubricant passing through the lubricant pathway.

A lubricant supply system is for a compressor that compresses a first working fluid in a heat transfer circuit. The lubricant supply system includes a lubricant tank, a lubricant pathway for supplying lubricant from the lubricant tank to one or more bearings of the compressor, and a lubricant refrigeration system with a lubricant heater and a lubricant cooler. The lubricant heater configured to heat the lubricant discharged from the one or more bearings and the lubricant cooler configured to cool the lubricant flowing through the lubricant pathway. A method of lubricating a compressor includes heating the lubricant, directing the lubricant from a lubricant tank through a lubricant pathway to one or more bearings of the compressor, and cooling the lubricant passing through the lubricant pathway.