Cooling structure for bearing device

A bearing device having a plurality of axially juxtaposed rolling bearings, each of the rolling bearings having an inner ring mounted on a main shaft and an outer ring accommodated in a housing;

• an inner ring spacer interposed between the inner rings of the neighboring rolling bearings and mounted on the main shaft;
• an outer ring spacer interposed between the outer rings of the neighboring rolling bearings and accommodated in the housing;
• and a cooling structure, wherein the cooling structure comprises:
• a nozzle provided in the outer ring spacer and configured to supply a cooling fluid to the rolling bearings by discharging the cooling fluid to an outer peripheral surface of the inner ring spacer, the cooling fluid including a compressed air,
• wherein the outer peripheral surface of the inner ring spacer is shaped to guide the cooling fluid, discharged from the nozzle, towards the neighboring rolling bearings on both sides,
• the nozzle for discharging the compressed air towards the outer peripheral surface of the inner ring spacer has a discharge port side that is provided in the outer ring spacer so as to incline forwardly with respect to the direction of rotation, and
• a radially protruding projection is defined in axial opposite side portions of the discharge port of the nozzle in the outer ring spacer or the inner ring spacer,
• wherein a first gap is formed between a radial tip end portion of the projection and a peripheral surface of the inner ring spacer, and
• the first gap is made smaller than a second gap present between the inner peripheral surface of the outer ring spacer, where the discharge port exists, and the outer peripheral surface of the inner ring spacer.

A bearing device having a plurality of axially juxtaposed rolling bearings, each of the rolling bearings having an inner ring mounted on a main shaft and an outer ring accommodated in a housing;

• an inner ring spacer interposed between the inner rings of the neighboring rolling bearings and mounted on the main shaft;
• an outer ring spacer interposed between the outer rings of the neighboring rolling bearings and accommodated in the housing;
• and a cooling structure, wherein the cooling structure comprises:
• a nozzle provided in the outer ring spacer and configured to supply a cooling fluid to the rolling bearings by discharging the cooling fluid to an outer peripheral surface of the inner ring spacer, the cooling fluid including a compressed air,
• wherein the nozzle has a discharge port side that is inclined forwardly with respect to a direction of rotation of the main shaft,
• the outer peripheral surface of the inner ring spacer is shaped to guide the cooling fluid, discharged from the nozzle, towards the neighboring rolling bearings on both sides, and
• a plurality of circumferentially juxtaposed holes are provided at a location of the outer peripheral surface of the inner ring spacer where the compressed air is discharged from the discharge port.

A bearing device having three or more of axially juxtaposed rolling bearings, including an intermediate rolling bearing and an end rolling bearing, each of the rolling bearings having an inner ring mounted on a main shaft and an outer ring accommodated in a housing;

• inner ring spacers interposed between the inner rings of neighboring rolling bearings and mounted on the main shaft;
• outer ring spacers interposed between the outer rings of neighboring rolling bearings and accommodated in the housing;
• and a cooling structure, wherein the cooling structure comprises:
• a nozzle provided in each of the outer ring spacers and configured to supply a cooling fluid to the neighboring rolling bearings by discharging the cooling fluid to an outer peripheral surface of each of the inner ring spacers, the cooling fluid including at least one of oil and air,
• wherein the nozzle has a discharge port side that is inclined forwardly with respect to a direction of rotation of the main shaft,
• the outer peripheral surfaces of each of the inner ring spacers is shaped to guide the cooling fluid, discharged from the nozzle, towards the neighboring rolling bearings on both sides,
• the outer ring spacers and the inner ring spacers are disposed between the outer rings of the neighboring rolling bearings and between the inner rings of the neighboring rolling bearings, respectively,
• of two of the outer ring spacers neighboring each other through the intermediate rolling bearing, one of these two outer ring spacers is operable to supply a mixture of the air and oil to the intermediate rolling bearing,
• the relationship between the flow rate or pressure of the cooling fluid discharged from the discharge port of one of the two outer ring spacers, which is positioned on an upstream side with respect to the direction of flow of the cooling fluid that is supplied to the intermediate rolling bearing, and from the discharge port of the other of the two outer ring spacers, which is positioned on a downstream side with respect to the direction of flow of the cooling fluid, is such that the cooling fluid discharged from the cooling fluid discharge port of the outer ring spacer positioned on the downstream side is configured to prevent reversing the flow of the cooling fluid within the intermediate rolling bearing.