JP6050072B2 - Cooling structure of bearing device - Google Patents

Description

  The present invention relates to a cooling structure for a bearing device, for example, a main shaft of a machine tool and a cooling structure for a bearing incorporated in the main shaft.

  In a spindle device of a machine tool, it is necessary to suppress the temperature rise of the device to be small in order to ensure machining accuracy. However, recent machine tools have a tendency to increase the speed in order to improve the processing efficiency, and the heat generated from the bearing supporting the main shaft is also increasing as the speed increases. In addition, so-called motor built-in types in which a driving motor is incorporated in the apparatus are becoming more and more a cause of heat generation of the apparatus.

  The rise in the temperature of the bearing due to heat generation results in an increase in preload, and we want to suppress it as much as possible in consideration of higher speed and higher accuracy of the spindle. As a method of suppressing the temperature rise of the main shaft device, there is a method of cooling the shaft and the bearing by sending compressed air for cooling to the bearing (for example, Patent Document 1). In Patent Document 1, the shaft and the bearing are cooled by injecting cold air into the space between the two bearings at an angle in the rotational direction to form a swirling flow.

JP 2000-161375 A

  Since the cooling method using the compressed air has a high cooling effect, it can be expected to effectively suppress the temperature rise of the spindle device. However, when the cooling method using compressed air is applied to a grease lubricated bearing device, there is a possibility that the grease in the bearing is blown off by the compressed air and eliminated. Therefore, it is necessary to take measures to avoid the above situation.

  An object of the present invention is to provide a cooling structure capable of efficiently cooling a bearing device with compressed air and preventing grease in the bearing from being eliminated by compressed air in a grease lubricated bearing device. is there.

The cooling structure of the bearing device of the invention, interposed outer ring spacer and the inner ring spacer, respectively between the outer ring and the inner ring of a plurality of rolling bearings arranged in the axial direction, the outer ring and the outer ring spacer is disposed in the housing, the An inner ring and an inner ring spacer are fitted to a main shaft, and the rolling bearing is applied to a bearing device that is lubricated by grease sealed in a bearing space between the outer ring and the inner ring. supply ports set for supplying compressed air for cooling toward the outer circumferential surface of the inner ring spacer vignetting, the axial end face of the outer ring spacer, discharge port for discharging the compressed air supplied from the supply port provided is, the both axial ends of the inner ring spacer, disorders wall compressed air supplied from the supply port protrudes radially outwardly is prevent from flowing into the bearing space is set vignetting, outside of the disorder wall The diameter end is slightly on the inner peripheral surface of the outer ring. Wherein the opposed through between.

According to this configuration, the compressed air that has collided with the inner ring spacer is supplied to the bearing device and the bearing by supplying the compressed air for cooling toward the outer peripheral surface of the inner ring spacer from the supply port provided in the outer ring spacer. Takes away the heat of the spindle supported by the device. Thereby, the bearing device and the main shaft are efficiently cooled. Obstacle walls are provided at both ends of the inner ring spacer in the axial direction to prevent the compressed air from flowing into the bearing space, so that the grease enclosed in the bearing space may be removed by the compressed air. It is prevented. Therefore, a good lubrication state can be maintained.

In the cooling structure of the bearing device of the present invention, the outer diameter surface of the disorders walls, both when there in the axial direction of the tapered protruding amount is large to the outer diameter side as the side close to the rolling bearing, the outer ring spacer The outlet may be a notch .
With this configuration, the compressed air supplied from the supply port flows outward in the axial direction through the spacer space, which is the space between the inner ring spacer and the outer ring spacer, along the outer peripheral surface of the inner ring spacer. It is guided to the outer diameter side along the tapered outer diameter surface of the obstacle wall of the inner ring spacer, and is discharged from a notch provided in the axial end surface of the outer ring spacer. Thereby, the flow of the compressed air in the spacer space and the discharge of the compressed air from the spacer space become smooth. Further, since a smooth flow of compressed air is generated in the spacer space, the internal pressure of the spacer space becomes lower than the internal pressure of the bearing space, and the compressed air is suppressed from flowing into the bearing space.

The supply port and the notch may be displaced from each other in the circumferential direction.
If the circumferential positions are deviated from each other, the compressed air supplied from the supply port to the spacer space flows to the notch along the outer peripheral surface of the inner ring spacer, in addition to moving outward in the axial direction. Since the movement in the circumferential direction is accompanied, it takes a long time for the compressed air to contact the inner ring spacer, and the effect of cooling the bearing device and the main shaft is enhanced.

In the cooling structure of the bearing device according to the present invention, the rolling bearing has a seal member that seals the bearing space at an axial end of the outer ring, and an outer diameter side end of the obstacle wall is an outer diameter of the end surface of the inner ring. located on the outer diameter side than the side edge and located on the inner diameter side than the inner diameter side end of the end face of the outer ring has a shape in which the end face of the failure wall is opposed via the seal member and the gap, said seal member it may be one lifting a labyrinth seal effect and the failure wall.
As a result, the compressed air can be further prevented from flowing into the bearing space.

  The cooling structure for a bearing device according to the present invention can be suitably used for supporting the spindle of a machine tool. In that case, since the cooling effect of the main shaft is high, operation in a high-speed region is possible.

The cooling structure of the bearing device of the invention, interposed outer ring spacer and the inner ring spacer, respectively between the outer ring and the inner ring of a plurality of rolling bearings arranged in the axial direction, the outer ring and the outer ring spacer is disposed in the housing, the An inner ring and an inner ring spacer are fitted to a main shaft, and the rolling bearing is applied to a bearing device that is lubricated by grease sealed in a bearing space between the outer ring and the inner ring. supply ports set for supplying compressed air for cooling toward the outer circumferential surface of the inner ring spacer vignetting, the axial end face of the outer ring spacer, discharge port for discharging the compressed air supplied from the supply port provided is, the both axial ends of the inner ring spacer, disorders wall compressed air supplied from the supply port protrudes radially outwardly is prevent from flowing into the bearing space is set vignetting, outside of the disorder wall The diameter end is slightly on the inner peripheral surface of the outer ring. To face through between the bearing device by compressed air can be cooled efficiently, moreover possible to prevent the grease in the bearing is eliminated by compressed air.

It is sectional drawing of the bearing apparatus provided with the cooling structure which concerns on one Embodiment of this invention. It is the elements on larger scale of FIG. It is sectional drawing which cut | disconnected the inner ring | wheel spacer and the outer ring | wheel spacer of the same bearing apparatus by the plane perpendicular | vertical to an axial direction. It is the figure which expanded and represented a part of outer ring spacer of the same bearing device. It is sectional drawing of the bearing apparatus provided with the cooling structure which concerns on different embodiment of this invention. It is the figure which expanded and represented a part of outer ring spacer of the same bearing device. It is sectional drawing which cut | disconnected the inner ring | wheel spacer and the outer ring | wheel spacer of the bearing apparatus which concerns on further different embodiment of this invention by the plane perpendicular | vertical to an axial direction. It is sectional drawing which shows the state which integrated the bearing apparatus shown in FIG.5 and FIG.6 in the main shaft apparatus of a machine tool.

A cooling structure for a bearing device according to an embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 1, the bearing device J includes an outer ring spacer 4 and an inner ring spacer 5 interposed between outer rings 2 and 2 and between inner rings 3 and 3 of a plurality of rolling bearings 1 and 1 arranged in the axial direction. I am letting. An angular ball bearing is applied as each rolling bearing 1. These angular ball bearings are installed in a combination on the back surface, and counter bores are provided on the opposite sides of the contact angles on the outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring. A plurality of rolling elements 8 are interposed between the raceway surfaces of the inner and outer rings 3, 2, and these rolling elements 8 are held by a cage 9 in a circumferentially equidistant manner. The rolling bearings 1 and 1 are grease-lubricated, and seal members 31 and 32 that seal the bearing space S1 between the outer ring 2 and the inner ring 3 are attached to both ends of the outer ring 2 in the axial direction.

  The bearing device J is used, for example, for supporting a main shaft of a machine tool. In this case, as shown in FIG. 3, the outer ring 2 of each rolling bearing 1 is fixed in a housing 6, and the inner ring 3 is fixed to the main shaft 7. Fits to the outer peripheral surface.

The cooling structure of the bearing device J will be described.
In FIG. 1, a radial clearance δ <b> 1 is provided between the inner peripheral surface of the outer ring spacer 4 and the outer peripheral surface of the inner ring spacer 5, and an inner ring spacer is provided on the inner peripheral surface of the outer ring spacer 4. A supply port 10 is provided for supplying compressed air for cooling toward the outer peripheral surface of 5. In this example, as shown in FIG. 3, the number of the supply ports 10 is three, and each supply port 10 is equally distributed in the circumferential direction.

  As shown in FIGS. 1 and 3, an annular introduction groove 11 for introducing the compressed air A is provided on the outer peripheral surface of the outer ring spacer 4. The introduction groove 11 is provided in an intermediate portion in the axial direction on the outer peripheral surface of the outer ring spacer 4 and communicates with each supply port 10 through a connection hole 11a. Compressed air A is supplied to the introduction groove 11 from a compressed air supply device (not shown) provided outside the bearing device J through the compressed air introduction hole 46 provided in the housing 6.

  As shown in FIG. 1, both end portions in the axial direction of the inner ring spacer 5 are obstruction walls 33 projecting to the outer diameter side. In this example, the obstacle wall 33 has a tapered shape in which the protruding amount toward the outer diameter side is larger toward the side closer to the axial rolling bearing 1. Further, a notch 34 serving as a discharge port for the compressed air A supplied from the supply port 10 is provided on the axial end surface of the outer ring spacer 4. For example, the notch 34 has a rectangular cross-sectional shape as shown in FIG. 4, and the outer ring 2 of the rolling bearing 1 is disposed adjacent to the outer ring spacer 4, so that the notch 34 is formed between the outer ring spacer 4 and the inner ring spacer. It becomes an opening shape which communicates between the space S2 between the seats 5 and the outside of the bearing device J. In this configuration, in order to assemble the outer ring spacer 4 (in order to prevent interference between the inner periphery of the outer ring spacer 4 and the obstacle wall 33), the inner ring spacer 5 is divided, for example, in the axial intermediate portion. It consists of two inner ring spacer divided bodies.

  As shown in FIG. 2, which is a partially enlarged view of FIG. 1, the outer diameter end of the obstacle wall 33 faces the inner peripheral surface of the outer ring spacer 4 with a slight radial clearance δ2. Further, the end face of the obstacle wall 33 faces the axially inner sealing member 31 with a slight axial clearance δ3. Thereby, the labyrinth seal portion 35 having a labyrinth seal effect is constructed by the seal member 31 and the obstacle wall 33, and the bearing space S1 and the spacer space S2 are separated by the labyrinth seal portion 35.

  In the bearing device J, the cooling compressed air A sent from the compressed air supply device provided outside the bearing device J during operation is supplied from the supply port 10 of the outer ring spacer 4 to the outer peripheral surface of the inner ring spacer 5. Supplied towards The compressed air A collides with the inner ring spacer 5, then flows axially along the outer peripheral surface of the inner ring spacer 5, and further flows along the tapered outer diameter surface of the obstacle wall 33 of the inner ring spacer 5. It is guided to the radial side and discharged from the notch 34 of the outer ring spacer 5. By guiding the compressed air A to the outer diameter side by the obstacle wall 33, the flow of the compressed air A in the spacer space S2 and the discharge of the compressed air A from the spacer space S2 become smooth. While the compressed air A passes through the spacer space S2, the heat of the bearing device J and the main shaft 7 supported by the bearing device J is taken away. Thereby, the bearing device J and the main shaft 7 are efficiently cooled.

By the opposite axial ends of the inner ring spacer 5 fault wall 33 is provided, the compressed air A is no possible is Habame flowing into the bearing space S1. In particular, in this embodiment, since the bearing space S1 and the spacer space S2 are separated by a labyrinth seal portion 35, Ru is Habame from flowing into the bearing space S1 of the compressed air A more effectively. Furthermore, since the compressed air A flows smoothly in the spacer space S2, the internal pressure of the spacer space S2 is lower than the internal pressure of the bearing space S1, and the compressed air A hardly flows into the bearing space S1. For these reasons, the compressed air A can be prevented from flowing into the bearing space S1 as much as possible, and the grease enclosed in the bearing space S1 can be prevented from being removed by the compressed air A. Therefore, a good lubrication state can be maintained.

  In the above embodiment, the supply port 10 and the notch 34 are arranged at the same circumferential position, but the supply port 10 and the notch 34 are arranged in the circumferential direction as in the embodiment shown in FIGS. The positions may be shifted. When the circumferential positions of the supply port 10 and the notch 34 are shifted from each other, the compressed air A supplied from the supply port 10 to the spacer space S2 flows to the notch 34 along the outer peripheral surface of the inner ring spacer 5. Sometimes, in addition to the movement outward in the axial direction, the movement in the circumferential direction is accompanied, so that the time for the compressed air A to contact the inner ring spacer 5 becomes longer, and the effect of cooling the bearing device J and the main shaft 7 is enhanced.

  Further, when the rotation direction of the shaft supported by the bearing device J is constant like the main shaft 7 of the machine tool, the air discharge direction of each supply port 10 is set to the inner ring 3 (FIG. 1) as shown in FIG. ) And the rotation direction L1 of the main shaft 7 may be inclined forward. Each supply port 10 is linear and is offset (offset amount OS) from an arbitrary radial straight line L2 in a cross section perpendicular to the axis of the outer ring spacer 4 in a direction perpendicular to the straight line L2. It is in. Thus, when the air discharge direction of each supply port 10 is inclined, when the discharged compressed air A hits the outer peripheral surface of the inner ring spacer 5, the pressing force of the compressed air A can be applied to the inner ring spacer 5. And the operation of driving the main shaft 7 can be expected.

  FIG. 8 is a cross-sectional view showing a part of the spindle device of the machine tool in which the bearing device shown in FIGS. 5 and 6 is incorporated. In the bearing device J, the outer rings 2, 2 of the rolling bearings 1, 1 and the outer ring spacer 4 are fitted to the inner peripheral surface of the housing 6, and the inner rings 3, 3 and the inner ring spacer 5 of the rolling bearings 1, 1 are machine tools. The main shaft 7 is fitted on the outer peripheral surface. For example, the outer ring 2 and the outer ring spacer 4 have a clearance fit with respect to the housing 6, and the inner ring 3 and the inner ring spacer 5 have an interference fit with respect to the shaft 7. The outer ring 3 of the rolling bearing 1 on one side (right side of the figure) is positioned in the axial direction by the step portion 6 a of the housing 6, and the inner ring 3 of the rolling bearing 1 is positioned in the axial direction by the positioning spacer 41. The bearing device J is fixed to the housing 6 by pressing the outer ring presser 42 and the outer ring presser 43 against the outer ring 2 and the inner ring 3 of the other (left side in the figure) rolling bearing 1.

  The housing 6 and the outer ring retainer 43 are provided with a compressed air introduction hole 46 through which the compressed air A for cooling sent from the compressed air supply device 45 is introduced into the bearing device J. The compressed air introduction hole 46 communicates with the introduction groove 11 provided on the outer peripheral surface of the outer ring spacer 5. The housing 6 and the outer ring retainer 43 are provided with an exhaust hole 47, and the exhaust hole 47 communicates with the notch 34 of the outer ring spacer 5 through the connection hole 48.

  Since the cooling structure of the bearing device J has a high cooling effect on the bearing device J and the main shaft 7 as described above, the main shaft device can be operated in a high-speed region. For this reason, this bearing apparatus J can be used suitably for support of the main axis | shaft of a machine tool.

DESCRIPTION OF SYMBOLS 1 ... Rolling bearing 2 ... Outer ring 3 ... Inner ring 4 ... Outer ring spacer 5 ... Inner ring spacer 6 ... Housing 7 ... Main shaft 10 ... Supply port 31, 32 ... Seal member 33 ... Obstacle wall 34 ... Notch 35 ... Labyrinth seal part A Compressed air J Bearing device S1 Bearing space S2 Spacer δ2 Ring clearance

Claims (5)

Between the outer ring of a plurality of rolling bearings arranged in the axial direction and the outer ring spacer and the inner ring spacer is interposed respectively between the inner ring, the outer ring and the outer ring spacer is disposed in the housing, fitting the inner ring and the inner ring spacer is the main axis In the bearing device in which the rolling bearing is lubricated by grease sealed in a bearing space between the outer ring and the inner ring,
The inner peripheral surface of the seat between the outer ring, the supply port for supplying compressed air for cooling toward the outer circumferential surface of the inner ring spacer is set vignetting, the axial end face of the outer ring spacer, supplied from the supply port Discharge ports for discharging the compressed air are provided , and the obstruction that prevents the compressed air supplied from the supply port from flowing into the bearing space by projecting to the outer diameter side at both axial ends of the inner ring spacer wall set vignetting, radially outer end of the disorder wall cooling structure of the bearing apparatus characterized by opposed through a slight gap to the inner peripheral surface of the outer ring. In the cooling structure of the bearing device according to claim 1, the outer diameter surface of said fault wall, with the amount of projection of the outer diameter side as the side closer to the axial direction of the rolling bearing is large tapered between said outer ring A cooling structure for a bearing device, wherein the outlet of the seat is a notch .   The cooling structure for a bearing device according to claim 2, wherein the supply port and the notch are displaced from each other in the circumferential direction. 4. The cooling structure for a bearing device according to claim 1, wherein the rolling bearing includes a seal member that seals the bearing space at an axial end of the outer ring, and outer diameter end is located on the inner diameter side than the inner diameter side end of the end surface of and and the outer ring located on the outer diameter side than the outer diameter end of the end face of the inner ring, the end face of the failure wall the sealing member and the gap through a shaped facing, the cooling structure of the seal member and the failure wall and lifting one bearing device a labyrinth seal effect.   The cooling structure for a bearing device according to any one of claims 1 to 4, which is used for supporting a main shaft of a machine tool.

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