JP2012071398A - Spindle device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spindle device which is increased in rigidity to improve the machining accuracy and can stably and reliably supply the base oil of grease to the raceway surfaces of the outer rings of angular ball bearings which are positioned on the front end side of a spindle.SOLUTION: This spindle device is configured by supporting the spindle 20 by the plurality of angular ball bearings installed in a housing while the rear surfaces thereof face each other. A grease container 2 filled with grease is provided to the inner periphery of the outer ring 3 on the rear side of the angular ball bearing positioned on the front end side of the spindle 20. A gap formation piece the front end of which is positioned near the raceway surface of the outer ring 3 and which forms a gap allowing the base oil of the grease in the grease container 2 to seep therethrough is provided to the grease container 2.

Description

  The present invention relates to a spindle device, and more particularly to a technique in which a rolling bearing device with a grease container provided with a grease container is applied to a spindle device for a machine tool.

As a lubrication method for a rolling bearing used in a spindle device for machine tools, there is a grease lubrication method that can be used without maintenance. Various types of rolling bearings with a lubrication function that are used for grease lubrication have been proposed (Patent Documents 1 to 3).
For example, as shown in FIG. 21, a spacer 51 is provided adjacent to the outer ring 50, and a grease reservoir forming component 52 (grease container 52) is provided on the inner periphery of the spacer 51. A step surface 53 following the outer ring raceway surface 50 a is provided, a part of the tip surface of the gap forming piece 54 of the grease reservoir forming component 52 is brought into contact with the step surface 53, and the gap between the tip surface and the step surface 53 is The base oil of grease is guided to the outer ring raceway surface 50a in the radial direction (Patent Document 3).

Japanese Patent No. 4234127 Japanese Patent No. 4256391 JP 2010-19268 A

  As shown in FIG. 22, when the rolling bearing formed of an angular ball bearing is used in combination with the back surface, a step is formed on the opposite side of the outer ring 50 on the side opposite to the bias side of the action line that forms a contact angle with the outer ring raceway surface. Surfaces and grease containers 52 must be provided. Conversely, if the step surface and the grease container 52 are provided on the biased side of the line of action that forms the contact angle, the raceway surface cannot be formed. In the case where the step surface and the grease container 52 are provided on the side opposite to the biased side of the line of action forming the contact angle, of the pair of angular ball bearings, the angular ball bearing disposed on the front end side of the spindle 20 close to the machining point. The distance from the intersection P1 between the line of action that forms a contact angle with the raceway surface of the outer ring 50 and the axial center L1 of the main shaft 20 to the machining point becomes long. If it does so, it will be difficult to raise the rigidity of a spindle apparatus, and it will become difficult to aim at improvement in processing accuracy.

  When a pair of angular contact ball bearings is used in combination with the back and vertical shaft, the rolling bearing near the lower side, that is, the machining point side (located on the front end side of the spindle) can be expected to be lubricated by surface tension, capillary action, etc. Since the grease reservoir forming component is disposed below the bearing, the base oil of the grease may not satisfy the desired supply amount.

  In the conventional example of FIG. 21, the gap base piece 54 is brought into contact with the stepped surface 53 so that the gap is accurately managed and the grease base oil is supplied. There's a problem. When the tip surface of the gap forming piece 54 is worn by fretting due to vibration of a spindle device for a machine tool spindle, the gap may be out of a desired range.

The object of the present invention is to increase the rigidity of the spindle device and improve the machining accuracy, and to stably and reliably supply grease base oil to the raceway surface of the outer ring of the angular ball bearing located on the front end side of the spindle. It is to provide a spindle device that can do this.
Another object of the present invention is to provide a spindle device capable of preventing fretting wear of a gap forming piece due to vibration of the spindle device or the like.

  The spindle device according to the present invention is a spindle device in which a spindle whose front end is a support part for a tool or a workpiece is supported by a plurality of angular ball bearings installed in a housing in combination with the back surface, and the angular device located on the front end side of the spindle. A grease container in which grease is accumulated is provided behind the ball bearing and on the inner periphery of the outer ring or next to the outer ring. The grease container has a tip positioned near the raceway surface of the outer ring. A gap forming piece for forming a gap through which the base oil of the grease is oozed is provided.

Grease is initially sealed in the grease container and each angular ball bearing. In an angular contact ball bearing located on the front end side of the spindle, the grease container located on the rear side of this bearing is repeatedly operated during a heat cycle in which the temperature rises and falls due to repeated operation stop and restart of this bearing. As the temperature rises, the internal pressure in the sealed grease container increases.
As the internal pressure in the grease container increases, the grease in the grease container and the base oil in the grease move toward the tip of the gap forming piece. Thereafter, the base oil in the grease container oozes from the tip of the gap forming piece via the thickener present in the gap due to capillary action in the grease existing in the gap. At the same time, the grease in the grease container moves toward the tip of the gap forming piece due to the capillary phenomenon of the entire gap. Accordingly, the base oil that has oozed out from the tip of the gap forming piece is supplied to the raceway surface of the outer ring. As a result, the base oil of grease is supplied to the raceway surface of the outer ring, and the amount of oil contributing to bearing lubrication can be increased.

  In addition, a pair of angular contact ball bearings is a rear combination, and the angular contact ball bearing on the front end side of the spindle is located on the rear side of this bearing, and is a grease container in which grease is accumulated inside, adjacent to the inner periphery of the outer ring or the outer ring. The following effects are obtained. With respect to the angular ball bearing on the front end side of the spindle, the distance from the intersection of the line of contact forming the contact angle with the raceway surface of the outer ring and the axis of the main shaft to the machining point is shorter than that of the conventional example. be able to. Thereby, it is possible to increase the rigidity of the spindle device and increase the processing accuracy.

  A grease container in which grease is stored is provided at the rear side of the angular ball bearing located at the rear end side of the spindle and at the inner periphery of the outer ring or adjacent to the outer ring, and the grease container is provided with a raceway surface of the outer ring. You may provide the clearance gap formation piece which forms the clearance gap where a front-end | tip part is located in the vicinity and the base oil of grease in a grease container oozes out.

  Also in the angular ball bearing on the rear end side of this spindle, the internal pressure in the grease container due to the heat cycle described above increases the grease in the grease container and the base oil in the grease at the tip of the gap forming piece. Move towards. Thereafter, the base oil in the grease container oozes from the tip of the gap forming piece via the thickener present in the gap due to capillary action in the grease existing in the gap. At the same time, the grease in the grease container moves toward the tip of the gap forming piece due to the capillary phenomenon of the entire gap. Therefore, the base oil oozed out from the tip of the gap forming piece is continuously and stably supplied to the raceway surface of the outer ring.

  When a grease container is provided on the rear side of the angular ball bearing located on the rear end side of the spindle, the angular ball bearing located on at least the front end side of the spindle among the plurality of angular ball bearings. The gap forming piece of the provided grease container may supply the base oil of the grease in the axial direction to the raceway surface of the outer ring. Thus, the gap forming piece has a structure in which the base oil is supplied in the axial direction to the raceway surface of the outer ring. Can be placed on either side of Even when the grease container is arranged on either the biased side or the opposite side, a compatible outer ring having the same shape and size can be used, so that the manufacturing cost can be reduced.

  When supplying the base oil of the grease in the axial direction, the gap forming piece of the grease container provided with respect to the angular ball bearing located at least on the front end side of the spindle among the plurality of angular ball bearings, The tip portion may face the inner circumferential surface portion extending in the axial direction and adjacent to the raceway surface of the outer ring through the gap. In this case, the wall thickness of the outer ring can be secured larger than that of the conventional outer ring provided with a step surface following the outer ring raceway surface, and the bearing rigidity can be increased.

When the tip of the gap forming piece faces the inner circumferential surface portion of the outer ring through the gap, the inner circumferential surface portion adjacent to the raceway surface of the outer ring extends along the edge of the raceway surface. An annular inclined oil guide surface having an inclination approaching the bottom of the raceway surface as it approaches the raceway surface, and a cylindrical surface portion continuing from the inclined oil guide surface to the opposite side of the raceway surface, and forming this gap and the gap It is good also as what forms the said clearance gap between pieces.
In this case, the initially charged grease adheres to the inclined oil guide surface. Even if this adhesion is insufficient, the grease initially sealed in the rolling bearing is scattered by centrifugal force due to the operation of the bearing, and a part thereof adheres to the inclined oil guide surface. Thereby, the grease in the grease container, the inclined oil guide surface, and the raceway surface of the outer ring are connected. When the base oil in the grease on the inclined oil guide surface is reduced, the base oil in the grease container is not separated from the thickener of the grease on the inclined oil guide surface due to the capillary phenomenon in the grease existing in the gap. It oozes out from the gap at the tip of the gap forming piece via the thickener present inside. At the same time, the grease in the grease container is supplied from the gap at the tip of the gap forming piece to the inclined oil guide surface due to the capillary phenomenon of the entire gap. At the same time, as the internal pressure in the grease container increases due to the heat cycle, the base oil of the grease in the grease container is discharged from the gap. Thereafter, the supply of the grease base oil is repeated.
Moreover, since the said clearance gap is formed between the cylindrical surface part of an outer ring | wheel, and a clearance gap formation piece, the front-end | tip part of a clearance gap formation piece extends in an axial direction, and is located in the vicinity of an inclination oil guide surface. Thereby, even when vibration or the like occurs in the spindle device, the tip of the gap forming piece can be separated from other components by the length of the inclined oil guide surface in the axial direction to prevent interference. Therefore, there is no possibility that the tip of the gap forming piece is worn by fretting.

When the inner peripheral surface portion is composed of the inclined oil guide surface and the cylindrical surface portion, the gap forming piece may extend to a part of the inclined oil guide surface. In this case, as the internal pressure in the grease container increases, the grease in the grease container and the base oil in the grease move toward the tip of the gap. Thereafter, due to capillary action in the grease existing in the gap, the base oil in the grease container accumulates at the tip of the gap forming piece via the thickener present in the gap as a passage. At the same time, the grease in the grease container moves toward the tip of the gap forming piece due to the capillary phenomenon of the entire gap.
After that, if the amount of base oil accumulated at the tip of the gap forming piece increases, the base oil swells at this tip, and the weight of this swelled portion becomes heavy and cannot be held by surface tension etc. Apart from the forming piece, the base oil itself falls on the inclined oil guide surface to the vicinity of the raceway surface by its own weight. For example, when used on the horizontal axis, there is a part of the entire circumference where the inclined oil guide surface is inclined downward with respect to the raceway surface. In this downward inclined part, the oil is discharged and adhered to the inclined oil guide surface. The base oil of grease moves along the inclined surface toward the bottom of the raceway surface by its own weight. In this case, even if the grease is not connected between the raceway surface and the inclined oil guide surface, it slides down along the inclined oil guide surface due to its own weight. Particularly, since the tip position of the gap forming piece is a position that protrudes in the axial direction from the circumferential surface adjacent to the guide surface to a part of the inclined oil guide surface, the base oil that swells and falls at the tip of the gap forming piece is inclined oil. It surely falls on the inclined surface of the guide surface, and moves smoothly and efficiently along this inclined surface. Thus, even if grease is not connected between the raceway surface and the inclined oil guide surface, the grease base oil is reliably supplied to the raceway surface. Of course, even if grease is connected over the raceway surface and the inclined oil guide surface, the grease base oil can be reliably supplied to the raceway surface as described above.

A grease container for each angular ball bearing may be provided on the inner periphery of the outer ring. Since the grease container is provided on the inner periphery of the outer ring as a bearing component in this way, the number of parts is reduced compared to a structure in which the grease container is disposed on the inner periphery of the outer ring spacer, and the entire bearing device is compact. Can be achieved.
A grease container for each angular ball bearing may be provided on the inner periphery of the outer ring spacer adjacent to the outer ring. In this case, a material having a standard outer ring width can be used, and the manufacturing cost can be reduced.

Four or more angular ball bearings are installed. These angular ball bearings are arranged side by side on the front end side of the spindle with the front side facing the front end side of the spindle, and the front side is the rear end of the spindle. It is good also as what was installed side by side toward the end side.
The spindle may be installed in a standing posture.
The spindle may be installed in a standing posture with the front end facing downward. In this case, for the angular ball bearing on the front end side of the spindle close to the machining point, since the grease container is disposed above the bearing, the grease in the grease container moves smoothly to the tip end side of the gap forming piece by its own weight. . The base oil of the grease in the grease container is also easily moved from the gap at the tip of the gap forming piece to the raceway side of the outer ring due to its own weight.

The spindle device according to the present invention is a spindle device in which a spindle whose front end is a support part for a tool or a workpiece is supported by a plurality of angular ball bearings installed in a housing in combination with the back surface, and the angular device located on the front end side of the spindle. A grease container in which grease is accumulated is provided behind the ball bearing and on the inner periphery of the outer ring or next to the outer ring. The grease container has a tip positioned near the raceway surface of the outer ring. A gap forming piece for forming a gap for oozing out the base oil of the inner grease was provided. For this reason, the rigidity of the spindle device can be increased, the processing accuracy can be improved, and the grease base oil can be stably and reliably supplied to the raceway surface of the outer ring of the angular ball bearing located on the front end side of the spindle. it can.
When the tip of the gap forming piece faces the inner circumferential surface portion of the outer ring through the gap, the inner circumferential surface portion adjacent to the raceway surface of the outer ring extends along the edge of the raceway surface. An annular inclined oil guide surface having an inclination approaching the bottom of the raceway surface as it approaches the raceway surface, and a cylindrical surface portion continuing from the inclined oil guide surface to the opposite side of the raceway surface, and forming this gap and the gap When the gap is formed between the two pieces, fretting wear of the gap-forming piece due to vibration of the spindle device or the like can be prevented.

(A) is sectional drawing of the spindle apparatus based on 1st Embodiment of this invention, (B) is sectional drawing which expands and shows the spindle and bearing apparatus of the spindle apparatus partially. (A) is sectional drawing of the rolling bearing apparatus with a grease container of the spindle front end side of the spindle apparatus, (B) is sectional drawing which expands and shows the principal part of the bearing apparatus. It is sectional drawing which expands and shows the cage | basket guide surface vicinity of the outer ring | wheel in the same bearing apparatus. It is sectional drawing which expands and shows the grease container etc. in the same bearing apparatus. (A) is sectional drawing of the rolling bearing apparatus with a grease container of the spindle rear end side of the spindle apparatus, (B) is sectional drawing which expands and shows the principal part of the bearing apparatus. It is the schematic explaining the effect of the bearing apparatus. (A) is the schematic explaining the effect of the spindle apparatus, (B) is the schematic explaining the effect of the spindle apparatus based on a prior art. (A) is sectional drawing of the rolling bearing apparatus with a grease container of the spindle front end side of the spindle apparatus which concerns on other embodiment of this invention, (B) is sectional drawing which expands and shows the principal part of the bearing apparatus. is there. (A) is sectional drawing of the rolling bearing apparatus with a grease container of the spindle rear end side of the spindle apparatus, (B) is sectional drawing which expands and shows the principal part of the bearing apparatus. It is the schematic explaining the effect of the bearing apparatus. (A) is sectional drawing of the rolling bearing apparatus with a grease container concerning other embodiment of this invention, (B) is sectional drawing which expands and shows the principal part of the bearing apparatus. It is sectional drawing of the rolling bearing apparatus with a grease container which concerns on the modification which changed the bearing apparatus partially, and made the contact angle reverse direction with respect to the bearing apparatus. (A) is sectional drawing of the rolling bearing apparatus with a grease container concerning other embodiment of this invention, (B) is sectional drawing which expands and shows the principal part of the bearing apparatus. (A) is sectional drawing of the rolling bearing apparatus with a grease container concerning other embodiment of this invention, (B) is sectional drawing which expands and shows the principal part of the bearing apparatus. It is sectional drawing of the rolling bearing apparatus with a grease container which concerns on other embodiment of this invention. It is sectional drawing of the spindle apparatus which concerns on other embodiment of this invention. It is sectional drawing of the spindle apparatus which concerns on other embodiment of this invention. It is sectional drawing of the spindle apparatus which concerns on other embodiment of this invention. It is sectional drawing of the spindle apparatus which concerns on other embodiment of this invention. It is an expanded sectional view which expands and shows the spindle and angular contact ball bearing of the spindle device partially enlarged. It is sectional drawing of the rolling bearing used for the conventional spindle apparatus for machine tools. It is an expanded sectional view of the principal part of the conventional spindle apparatus.

  A first embodiment of the present invention will be described with reference to FIGS. The spindle device for a machine tool according to this embodiment uses a rolling bearing device with a grease container provided with a grease container. First, the overall configuration of the spindle device will be described, and then the rolling bearing devices with grease containers on the front end side and the rear end side of the spindle will be sequentially described.

  As shown in FIGS. 1A and 1B, for example, the angular ball bearing of FIG. 2A is arranged on the front end side of the spindle 20 (main shaft 20), and the angular ball bearing of FIG. The two angular ball bearings are arranged on the rear end side of 20 and are installed in the housing 21 in a combination of the back surfaces. Two angular ball bearings rotatably support both ends of the spindle 20. The inner ring 4 of each angular ball bearing is positioned in the axial direction by inner ring positioning spacers 22 and 22 and step portions 20 a and 20 a of the spindle 20, and is fastened and fixed to the spindle 20 by an inner ring fixing nut 23. The outer ring 3 is positioned and fixed in the housing 21 by an outer ring spacer 24 and outer ring pressing lids 25, 25. The housing 21 is formed by fitting a housing inner cylinder 21a and a housing outer cylinder 21b, and an oil passage groove 21c for cooling is provided in the fitting portion.

  The front end 20b of the spindle 20 serves as a tool or workpiece support, and the rear end 20c of the spindle 20 is connected to a drive source such as a motor via a rotation transmission mechanism (not shown). The motor may be built in the housing 21. This spindle apparatus can be applied to various machine tools such as a machining center, a lathe, a milling machine, and a grinding machine.

A rolling bearing device with a grease container on the front end side of the spindle will be described with reference to FIGS.
As shown in FIG. 2A, this rolling bearing device with a grease container has a rolling bearing 1 and a grease container 2. The rolling bearing 1 is an angular ball bearing, and in the example of FIG. 2A, the grease container 2 is provided on the back side of the outer ring that receives an axial load. Further, the grease container 2 is mounted in the bearing space so as to be fixed in position with respect to the outer ring 3 that is the stationary side race ring, and is configured to store grease in the grease container 2. As will be described later, the base oil of the grease in the grease container 2 is supplied to the raceway surface 3a of the stationary raceway.

The rolling bearing 1 includes an inner ring 4, an outer ring 3, a plurality of rolling elements 5, a cage 6, and a seal 7, and the plurality of rolling elements 5 are interposed between the raceway surfaces 4 a and 3 a of the inner and outer rings 4 and 3. These rolling elements 5 are held at regular intervals in the circumferential direction by a cylindrical cage 6. One end in the axial direction between the inner and outer rings 4, 3, that is, one end on the bearing front side is sealed with a seal 7.
The outer ring 3 is provided with an outer ring extension 3 b extending in the width direction for forming the grease container 2. The outer ring extension 3b extends in the width direction according to the capacity of the grease container 2 and the like from the biased side of the action line 3c that forms a contact angle with the raceway surface 3a of the outer ring 3.

  As shown in FIG. 2B, the inner peripheral surface portion 8 adjacent to the right side of the raceway surface 3a of the outer ring 3 is composed of an annular inclined oil guide surface 8a and a cylindrical surface portion 8b. Among these, the inclined oil guide surface 8a is provided at a position following the biased side of the action line 3c that forms a contact angle with the raceway surface 3a of the outer ring 3. The inclined oil guide surface 8a has an inclination that approaches the bottom of the raceway surface 3a along the edge of the raceway surface 3a of the outer ring 3 as it approaches the raceway surface 3a. By the operation of the bearing, the grease initially sealed in the rolling bearing 1 is scattered by centrifugal force, and a part thereof adheres to the inclined oil guide surface 8a. The cylindrical surface portion 8b continues from the inclined oil guide surface 8a to the side opposite to the track surface 3a.

  As shown in FIG. 3, a small-diameter inner peripheral surface portion 9 is provided on the inner peripheral surface adjacent to the left side of the raceway surface 3a of the outer ring 3, that is, on the inner peripheral surface opposite to the inclined oil guide surface 8a. The small-diameter inner peripheral surface portion 9 is formed with a smaller diameter than the inner peripheral surface portion on the inclined oil guide surface side. The small-diameter inner peripheral surface portion 9 having a small diameter is used as a guide surface for the cage 6. That is, the outer peripheral surface 6 a of the cage 6 is guided by the small-diameter inner peripheral surface portion 9. An outer ring seal groove 10 is formed at an end of the outer ring inner peripheral surface adjacent to the small diameter inner peripheral surface portion 9, and a seal 7 is fitted and fixed to the outer ring seal groove 10.

As shown in FIG. 2 (A), the inner ring 4 is also provided with an inner ring extension 4b extending in the width direction. The inner ring extension 4b is located on the inner ring side of the outer ring extension 3b and the grease container 2. The full width dimension of the inner ring 4 including the inner ring extension portion 4b is defined to be substantially the same as the full width dimension of the outer ring 3.
An inner ring outer peripheral surface 4c adjacent to the right side of the raceway surface 4a of the inner ring 4 is formed, and a small diameter outer peripheral surface portion 4e having a smaller diameter than the inner ring outer peripheral surface 4c is formed on the inner ring outer peripheral surface 4c via a step portion 4d. It is formed. A predetermined radial gap δ1 is formed between the small-diameter outer peripheral surface portion 4e and the grease container 2, so that interference between the inner ring 4 and the grease container 2 is prevented. As shown in FIG. 3, an inner ring seal groove 11 is formed at an end portion of the inner ring outer peripheral surface 4f adjacent to the left side of the raceway surface 4a of the inner ring 4 in the figure.

The grease container 2 and the like will be described.
As shown in FIG. 4, the grease container 2 is provided with a gap forming piece 12 that extends in the axial direction and has a tip portion 12 a positioned in the vicinity of the inclined oil guide surface 8 a. A gap δ <b> 2 for oozing out the base oil of the grease in the grease container 2 is formed at the distal end portion 12 a of the gap forming piece 12. The grease container 2 has a groove-shaped grease container main body 13 that is open on the outer peripheral surface side. The grease container main body 13 is inclined in the radial direction from the cylindrical bottom surface portion 13a and one axial end edge of the bottom surface portion 13a. It has one side wall part 13b standing upright and the other side wall part 13c standing up radially outward from the other axial end edge of the bottom surface part 13a. The gap forming piece 12 extends from the outer diameter side end of the one side wall portion 13b of the grease container body 13 to the axial rolling element side. The one side wall portion 13b has an inclination angle that inclines inward of the bearing as it goes radially outward from the inner diameter side end.

  An annular positioning notch 14 for positioning the grease container 2 with respect to the outer ring 3 is formed on the inner peripheral surface of the outer ring extension 3 b in the outer ring 3. The positioning cutout portion 14 is formed at an end portion of the inner peripheral surface of the outer ring extension 3b, and includes a cylindrical inner peripheral surface portion 14a and a stepped portion 14b following the inner peripheral surface portion 14a. An escape portion 14c is annularly provided at the corner between the inner peripheral surface portion 14a and the stepped portion 14b. An outer diameter side end of the other side wall 13c is engaged with the positioning cutout 14. The outer diameter side end of the other side wall 13c of the grease container main body 13 is fitted and fixed to the inner peripheral surface portion 14a of the positioning notch 14 so that the radial position of the grease container 2 is positioned relative to the outer ring 3. Is done. At the same time, the inner side surface of the outer diameter side end of the other side wall portion 13c contacts the stepped portion 14b of the positioning notch portion 14, whereby the axial position of the grease container 2 is positioned with respect to the outer ring 3. . In addition, since the relief part 14c was provided in the corner part of the internal peripheral surface part 14a and the step part 14b, interference with the corner | angular part of the outer-diameter side end of the other side wall part 13c and the said corner part can be prevented. Thereby, the grease container 2 can be accurately positioned with respect to the outer ring 3.

  The outer ring extension 3b is formed with a grease filling hole 15 for filling the grease in the grease container 2. The grease sealing hole 15 is formed of a female screw that penetrates in the radial direction. A male screw member (not shown) that is screwed into the grease sealing hole 15 to seal the grease sealing hole 15 is provided. In place of the configuration in which the outer ring extension 3b is provided with the grease sealing hole 15, the other side wall 13c of the grease container body 13 is provided with a grease sealing hole 15 penetrating in the axial direction, and is a male screw that is screwed into the grease sealing hole 15. You may make it the structure which provided the member.

  As shown in FIGS. 2B and 4, the gap forming piece 12 faces the inner peripheral surface of the outer ring 3, and the gap is formed between the outer ring inner peripheral surface and the tip end portion 12 a of the gap forming piece 12. δ2 is formed. That is, as shown in an enlarged view in FIG. 2B, the tip end portion 12a of the gap forming piece 12 extends in the axial direction and is located in the vicinity of the inclined oil guide surface 8a. The gap δ2, that is, the radial gap δ2 is formed between the cylindrical surface portion 8b and the tip end portion 12a of the gap forming piece 12. Further, the gap forming piece 12 extends from the outer diameter side end of the one side wall portion 13b of the grease container body 13 toward the axial rolling element side, and the base oil of the grease in the grease container 2 is supplied to the raceway surface 3a of the outer ring 3. It is configured to supply in the axial direction.

  A rolling bearing device with a grease container on the rear end side of the spindle will be described with reference to FIG. Here, FIG. 5A relates to a modified form in which the rolling bearing device with a grease container shown in FIG. 2 is partially changed, and the rolling bearing with a grease container in which the direction of the contact angle is opposite to that of the bearing device. FIG. 5B is a cross-sectional view showing an enlarged main part of the bearing device. In the example of FIG. 5, the grease container 2 is provided on the front side of the outer ring that does not receive an axial load. As shown in FIG. 5 (A), the outer ring extension 3b extends in the width direction from the side opposite to the biased side of the action line 3c that forms a contact angle with the raceway surface 3a of the outer ring 3. As shown in FIG. 5 (B), the inclined oil guide surface 8a of the inner peripheral surface portion 8 of the outer ring 3 is on the opposite side to the biased side of the action line 3c that forms a contact angle with the raceway surface 3a of the outer ring 3. It is provided at the following position.

  As shown in FIG. 5A, an inner ring counter bore 4g made of an inclined surface is formed adjacent to the left side of the raceway surface 4a of the inner ring 4 in the figure. No inner ring seal groove is formed at the end of the inner ring counter bore 4g. An inner ring outer circumferential surface 4h adjacent to the right side of the raceway surface 4a of the inner ring 4 is formed, and a small diameter outer circumferential surface portion 4j having a smaller diameter than the inner ring outer circumferential surface 4h is formed on the inner ring outer circumferential surface 4h via a stepped portion 4i. It is formed. The other configuration is the same as that of FIG.

Next, the effect of the rolling bearing device with a grease container will be described mainly with reference to FIG. “+” In FIG. 6 represents the base oil in the grease.
In general, grease is initially sealed in the grease container 2 and the rolling bearing 1. The initially charged grease adheres to the inclined oil guide surface 8a. Even if this adhesion is insufficient, the grease initially sealed in the rolling bearing 1 is scattered by centrifugal force due to the operation of the bearing, and a part of the grease adheres to the inclined oil guide surface 8a. As a result, the grease in the grease container 2, the inclined oil guide surface 8a, and the raceway surface 3a of the outer ring 3 are connected. The grease container 2 is sealed except for the gap δ2. The internal pressure in the sealed grease container 2 rises due to the temperature rise during operation in the heat cycle in which the temperature of the grease container 2 is repeatedly raised and lowered due to repeated operation stop and restart of the bearing.
When the base oil of the grease on the raceway surface 3a of the outer ring 3 decreases due to the operation of the bearing, the base oil in the grease on the inclined oil guide surface 8a is supplied to the raceway surface 3a. That is, only the base oil in the grease on the inclined oil guide surface 8a is supplied to the raceway surface 3a by capillary action. At the same time, for example, when used on the horizontal axis, a portion where the inclined oil guide surface 8a is inclined downward with respect to the raceway surface 3a occurs in the entire circumference. In this downward inclined portion, the inclined oil guide surface is formed. The base oil of grease adhering to 8a moves to the bottom side of the raceway surface 3a along the inclined surface by its own weight. Thus, since the inclined oil guide surface 8a is provided and the base oil is moved by its own weight, the grease base oil can be stably and reliably supplied to the raceway surface 3a.

  When the base oil in the grease on the inclined oil guide surface 8a decreases, the base oil in the grease container is reduced due to the capillary phenomenon in the grease existing in the gap δ2 against the thickener of the grease on the inclined oil guide surface 8a. Is exuded from the gap δ2 of the tip end portion 12a of the gap forming piece 12 through the thickener present in the gap δ2 as a passage. At the same time, the grease in the grease container 2 is supplied from the gap δ2 of the tip end portion 12a of the gap forming piece 12 to the inclined oil guide surface 8a by the capillary phenomenon of the entire gap δ2. At the same time, as the internal pressure in the grease container 2 increases due to the heat cycle, the base oil of the grease in the grease container 2 is discharged from the gap δ2. Thereafter, the supply of the grease base oil is repeated.

  Thus, the base oil of grease can be reliably supplied to the raceway surface 3a of the outer ring 3, and the amount of oil contributing to bearing lubrication can be increased. Further, since the tip end portion 12a of the gap forming piece 12 extends in the axial direction and is located in the vicinity of the inclined oil guide surface 8a, the tip end portion 12a of the gap forming piece 12 is equal to the axial length of the inclined oil guide surface 8a. , And can be separated from other parts (in this example, the rolling elements 5 etc.) to prevent interference. Therefore, the tip portion 12a of the gap forming piece 12 is not likely to be worn by fretting regardless of the vibration of the spindle device.

  As shown in FIG. 7A, the pair of angular ball bearings is a rear combination, and the angular ball bearing on the front end side (left side of the figure) of the spindle 20 is positioned on the rear side of the bearing, Since the grease container 2 in which grease is stored is provided on the periphery, the following operational effects can be obtained. With respect to the angular ball bearing on the front end side of the spindle 20, a distance L2 from the intersection P1 between the action line 3c that forms a contact angle with the raceway surface 3a of the outer ring 3 and the axial center L1 of the main shaft 20 to the machining point is defined as follows. This can be shortened from the conventional example shown in FIG. Thereby, it is possible to increase the rigidity of the spindle device and increase the processing accuracy.

  As shown in FIGS. 4 and 5A, the outer diameter side end of the side wall 13c inside the bearing of the grease container body 13 is engaged with an annular positioning notch 14 formed on the inner peripheral surface of the outer ring 3. Therefore, the following effects are obtained. The grease container 2 can be positioned on the outer ring 3 by simply engaging the outer diameter side end of the side wall 13c of the grease container body 13 with the positioning cutout 14, and the bearing device can be easily assembled. . Further, a retaining ring or the like for fixing the grease container 2 to the outer ring 3 can be eliminated, and the number of parts can be reduced.

As shown in FIGS. 2B and 5B, the gap forming piece 12 faces the inner peripheral surface of the outer ring 3 and is between the inner peripheral surface of the outer ring and the tip 12 a of the gap forming piece 12. Since the gap δ2 is formed, grease base oil can be supplied in the axial direction from the gap δ2. In order to supply the base oil of the grease in the axial direction, not in the radial direction, the grease container 2 is placed on either side of the acting line 3c that makes a contact angle with respect to the raceway surface 3a of the outer ring 3 and on the opposite side of the acting side Can also be placed. Even when the grease container 2 is disposed on either the biased side or the opposite side, the outer ring 3 can be used also, so that the manufacturing cost can be reduced.
Further, in order to form the gap δ2 between the inner peripheral surface of the outer ring and the tip end portion 12a of the gap forming piece 12, the thickness of the outer ring 3 is made larger than that of the outer ring provided with a step surface following the conventional outer ring raceway surface. A large amount can be secured and the bearing rigidity can be increased.

  Hereinafter, other embodiments of the present invention will be described. Portions corresponding to the matters described in the preceding embodiments in each embodiment are denoted by the same reference numerals, and overlapping description is omitted. When only a part of the configuration is described, the other parts of the configuration are the same as those described in advance, unless otherwise specified. From the same configuration, the same effects are obtained. Not only the combination of the parts specifically described in each embodiment, but also the embodiments can be partially combined as long as the combination does not hinder.

  The rolling bearing device with a grease container shown in FIGS. 8A and 8B is disposed, for example, on the front end side of the spindle 20 shown in FIG. 1, and is replaced with the bearing device shown in FIGS. 2A and 2B. Provided. The tip position 12aa of the tip portion 12a of the gap forming piece 12 of the grease container 2 protrudes in the axial direction from the cylindrical surface portion 8b to a part of the inclined oil guide surface 8a. A gap δ <b> 2 for oozing out the base oil of the grease in the grease container 2 is formed at the distal end portion 12 a of the gap forming piece 12.

  As shown in FIG. 8B, the gap forming piece 12 faces the inner peripheral surface of the outer ring 3, the cylindrical surface portion 8 b of the inner peripheral surface portion of the outer ring 3, and the distal end portion 12 a of the gap forming piece 12. In the meantime, the gap δ2 is formed. The tip position 12aa of the tip portion 12a of the gap forming piece 12 is a position that protrudes in the axial direction from the cylindrical surface portion 8b to a part of the inclined oil guide surface 8a. Between the cylindrical surface portion 8b of the inner peripheral surface portion 8 of the outer ring 3 and a part of the inclined oil guide surface 8a and the tip end portion 12a of the gap forming piece 12, the gap δ2, that is, the radial gap δ2 is formed. Form. Further, the gap forming piece 12 extends from the outer diameter side end of the one side wall portion 13b of the grease container body 13 toward the axial rolling element side, and the base oil of the grease in the grease container 2 is supplied to the raceway surface 3a of the outer ring 3. It is configured to supply in the axial direction.

  Here, FIG. 9 (A) relates to a modified form in which the rolling bearing device with a grease container of FIG. 8 (A) is partially changed, with the grease container having the contact angle direction opposite to that of the bearing device. A sectional view of the rolling bearing device, FIG. 9B is an enlarged sectional view showing the main part of the bearing device. In the example of FIG. 9, the grease container 2 is provided on the front side of the outer ring that does not receive an axial load. As shown in FIG. 9 (A), the outer ring extension 3b extends in the width direction from the side opposite to the biased side of the action line 3c that forms a contact angle with the raceway surface 3a of the outer ring 3. As shown in FIG. 9B, the inclined oil guide surface 8a of the inner peripheral surface portion 8 of the outer ring 3 is on the side opposite to the biased side of the action line 3c that forms a contact angle with the raceway surface 3a of the outer ring 3. It is provided at the following position.

  As shown in FIG. 9A, an inner ring counter bore 4g made of an inclined surface is formed adjacent to the left side of the raceway surface 4a of the inner ring 4 in the figure. No inner ring seal groove is formed at the end of the inner ring counter bore 4g. An inner ring outer circumferential surface 4h adjacent to the right side of the raceway surface 4a of the inner ring 4 is formed, and a small diameter outer circumferential surface portion 4j having a smaller diameter than the inner ring outer circumferential surface 4h is formed on the inner ring outer circumferential surface 4h via a stepped portion 4i. It is formed. The other configuration is the same as that of FIG.

Next, the function and effect of the rolling bearing device with a grease container of FIG. 9 will be described mainly with reference to FIG.
As shown in FIG. 10A, grease is generally initially sealed in the grease container 2 and the rolling bearing 1. The grease container 2 is sealed except for the gap δ2. The internal pressure in the sealed grease container 2 rises due to the temperature rise during operation in the heat cycle in which the temperature of the grease container 2 is repeatedly raised and lowered due to repeated operation stop and restart of the bearing.
As shown in FIG. 10 (b), the internal pressure in the grease container 2 and the base oil in the grease move toward the tip end portion 12a of the gap δ2 due to the increase in the internal pressure in the grease container 2. Thereafter, due to the capillary phenomenon in the grease existing in the gap δ2, the base oil in the grease container 2 accumulates at the distal end portion 12a of the gap forming piece 12 via the thickener existing in the gap δ2. . At the same time, the grease in the grease container 2 moves toward the distal end portion 12a of the gap forming piece 12 due to the capillary action of the entire gap δ2.

  Thereafter, as shown in FIG. 10 (c), when the amount of the base oil accumulated at the tip portion 12a of the gap forming piece 12 increases, the base oil swells at the tip portion 12a, and the weight of the swelled portion is increased. It becomes heavier and cannot be held by surface tension or the like, and is separated from the gap forming piece 12 and falls on the inclined oil guide surface 8a to the vicinity of the raceway surface 3a by its own weight. For example, when used on the horizontal axis, there is a portion of the entire circumference where the inclined oil guide surface 8a is inclined downward with respect to the raceway surface 3a. In this downward inclined portion, the oil is discharged onto the inclined oil guide surface 8a. The base oil of the grease thus attached moves along the inclined surface toward the bottom of the raceway surface 3a by its own weight. In this case, even if grease is not connected between the raceway surface 3a and the inclined oil guide surface 8a, the grease slides down along the inclined oil guide surface 8a due to the weight of the base oil. In particular, since the tip position 12aa of the gap forming piece 12 is a position protruding in the axial direction from the guide surface adjacent peripheral surface 8b to a part of the inclined oil guide surface 8a, the tip 12a of the gap forming piece 12 swells and falls. The base oil reliably falls on the inclined surface of the inclined oil guide surface 8a, and moves smoothly and efficiently along the inclined surface. Thus, even if grease is not connected across the raceway surface 3a and the inclined oil guide surface 8a, the grease base oil is reliably supplied to the raceway surface 3a. Of course, even if grease is connected over the raceway surface 3a and the inclined oil guide surface 8a, the grease base oil can be reliably supplied to the raceway surface 3a as described above. Thus, the base oil of grease can be reliably supplied to the raceway surface 3a of the outer ring 3, and the amount of oil contributing to bearing lubrication can be increased. Further, since the tip position 12aa of the gap forming piece 12 is defined as described above, there is no possibility that the tip portion 12aa of the gap forming piece 12 is worn by fretting. Therefore, the gap δ2 can be managed with high accuracy, and for example, the grease base oil can be stably supplied regardless of the vibration of the spindle device.

The gap forming piece 12 faces the inner peripheral surface of the outer ring 3 and forms a gap δ2 between the cylindrical surface portion 8b of the inner peripheral surface portion of the outer ring 3 and the tip end portion 12a of the gap forming piece 12. Therefore, the base oil of grease can be supplied in the axial direction from the gap δ2. In order to supply the base oil of the grease in the axial direction, not in the radial direction, the grease container 2 is placed on either side of the acting line 3c that makes a contact angle with respect to the raceway surface 3a of the outer ring 3 and on the opposite side of the acting side Can also be placed. Even when the grease container 2 is disposed on either the biased side or the opposite side, the outer ring 3 can be used also, so that the manufacturing cost can be reduced.
Further, in order to form the gap δ2 between the inner peripheral surface of the outer ring and the tip end portion 12a of the gap forming piece 12, the thickness of the outer ring 3 is made larger than that of the outer ring provided with a step surface following the conventional outer ring raceway surface. A large amount can be secured and the bearing rigidity can be increased.

  In the rolling bearing device with a grease container of FIG. 11A, an outer ring spacer 16 adjacent to the outer ring 3 is provided, and the grease container 2 is provided on the inner peripheral surface of the outer ring spacer 16. FIG. 11B is an enlarged cross-sectional view of a main part of FIG. In this example, an inner ring spacer 26 adjacent to the inner ring 4 is provided in place of the inner ring extension 4b. However, instead of the configuration in which the inner ring spacer 26 is provided, a configuration in which the inner ring extension 4b is provided as in FIG. According to the configuration of FIG. 11, materials having standard outer ring width and inner ring width can be used, and the manufacturing cost can be reduced.

  FIG. 12 is a cross-sectional view of a rolling bearing device with a grease container according to a modification in which the rolling bearing device with a grease container of FIG. 11 is partially changed, with the contact angle direction opposite to that of the bearing device. In the configuration of FIG. 12 as well, standard outer ring width and inner ring width materials can be used, and the manufacturing cost can be reduced.

  The rolling bearing device with a grease container of FIGS. 13A and 13B has a double structure in which the gap forming piece 12 is composed of an inner peripheral piece 17 and an outer peripheral piece 18. The gap δ2 is formed between them. The outer peripheral piece 18 extends inward of the bearing along the inner peripheral surface of the outer ring spacer 16 from the inner surface portion on the outer diameter side of the other side wall portion 13c. The distal end portion of the outer peripheral piece 18 is fitted and positioned in an annular positioning notch portion 14 provided at an end portion of the inner peripheral surface of the outer ring. The outer peripheral side end of the outer peripheral piece 18 is fitted and fixed to the inner peripheral surface portion 14 a of the positioning cutout portion 14, whereby the radial position of the grease container 2 is positioned with respect to the outer ring 3. At the same time, the axial position of the distal end portion of the outer peripheral piece 18 contacts the stepped portion 14 b of the positioning notch portion 14, whereby the axial position of the grease container 2 is positioned with respect to the outer ring 3.

With the outer peripheral piece 18 thus fitted and positioned in the positioning notch portion 14, between the cylindrical surface portion 8 b of the inner peripheral surface portion of the outer peripheral piece 18 and the outer peripheral surface of the inner peripheral piece 17. A gap δ2 in the radial direction is formed. The track surface 3a continues from the cylindrical surface portion 8b of the inner peripheral surface portion of the outer peripheral piece 18 through the inclined oil guide surface 8a.
In this case, the grease container 2 filled with grease can be easily handled by the grease container alone. Therefore, the grease container 2 filled with grease can be assembled to the rolling bearing 1 in a fixed position. In this case, since the grease filling operation after assembling the rolling bearing device with the grease container can be omitted, the number of work steps can be reduced.

  FIG. 14 is a cross-sectional view of a rolling bearing device with a grease container according to a modification in which the rolling bearing device with a grease container of FIG. 13 is partially changed, with the contact angle direction opposite to that of the bearing device. In the configuration of FIG. 14 as well, a grease container 2 filled with grease can be easily handled by the grease container alone, and the grease container 2 filled with grease can be assembled to the rolling bearing 1 in a fixed position. it can. In this case, since the grease filling operation after assembling the rolling bearing device with the grease container can be omitted, the number of work steps can be reduced.

  The rolling bearing device with a grease container in FIG. 15 is provided with a gas-filled bag 19 filled with compressed gas over the entire circumference of the bottom with respect to the outlet made of the gap δ 2 in the grease container 2. In the initial sealed state, grease is sealed in a state where the gas sealed bag 19 is contracted against the atmospheric pressure in the bag. In this case, the compressed air in the gas-filled bag 19 expands due to the temperature rise during the bearing operation, whereby the grease sealed in the grease container 2 is pushed out toward the gap δ2. At the same time, the base oil of the grease in the grease container 2 oozes stably from the gap δ2 by the capillary phenomenon and the heat cycle.

  As shown in FIG. 16, four or more angular ball bearings (in this example, four) are installed, and a plurality of these angular ball bearings are provided with the front end side of the spindle 20 facing the front end side of the spindle (this In the example, two spindles may be installed side by side, and a plurality of spindles (two in this example) may be installed side by side on the rear end side of the spindle 20 with the front side facing the rear end side of the spindle.

  The spindle device of FIG. 17 is a so-called belt-driven spindle device in which a drive source such as a motor (not shown) is connected via a rotation transmission mechanism 27. Three angular ball bearings are provided on the front end side of the spindle 20, and a double-row cylindrical roller bearing 28 is provided on the rear end side of the spindle 20. In this case, the rigidity of the spindle device and the like of FIG.

  The spindle device shown in FIG. 18 is a so-called built-in motor drive type spindle device in which a motor 29 is built in a housing 21. A rotor 29 a of a motor 29 is attached to the spindle 20, and a stator 29 b of the motor 29 is attached to the housing 21. The rotor 29a is made of a permanent magnet or the like, and the stator 29b is made of a coil, a core, or the like. Four angular ball bearings are provided on the front end side of the spindle 20, and a cylindrical roller bearing 30 is provided on the rear end side of the spindle 20. In this case, the speed can be increased as compared with the spindle device of FIGS.

  As shown in FIGS. 19 and 20, when a pair of angular ball bearings are used as a rear combination in a vertical spindle device, the angular ball bearings arranged on the side closer to the processing point are located above the bearings. Since the grease container 2 is disposed, the grease in the grease container 2 moves smoothly toward the tip portion 12a side of the gap forming piece 12 by its own weight. The base oil of the grease in the grease container 2 also easily moves from the gap δ2 at the tip 12 of the gap forming piece 12 to the inclined oil guide surface 8a due to the weight of the base oil itself. The base oil in the grease on the inclined oil guide surface 8a is also easily moved to the outer ring raceway surface 3a or the rolling element 5 due to its own weight. Thus, in the angular ball bearing disposed on the side close to the processing point, the grease base oil can be more reliably supplied to the outer ring raceway surface 3a. As for the angular ball bearing arranged on the side far from the machining point, the grease container 2 is arranged above the bearing, so that the base oil of grease is applied to the outer ring raceway surface 3a in the same manner as the angular ball bearing near the machining point. Can be supplied more reliably.

DESCRIPTION OF SYMBOLS 1 ... Rolling bearing 2 ... Grease container 3 ... Outer ring 3a ... Race surface 8 ... Inner peripheral surface part 8a ... Inclined oil guide surface 8b ... Cylindrical surface part 12 ... Gap formation piece 16 ... Outer ring spacer 20 ... Spindle 21 ... Housing

Claims (11)

In a spindle device in which a spindle whose front end is a support part for a tool or a workpiece is supported by a plurality of angular ball bearings installed in a housing in combination with the back side,
A grease container in which grease is stored is provided behind the angular ball bearing located on the front end side of the spindle and on the inner periphery of the outer ring or next to the outer ring, and in the vicinity of the raceway surface of the outer ring. A spindle device characterized in that a gap forming piece is provided in which a tip portion is positioned to form a gap through which the base oil of grease in the grease container oozes out.   In Claim 1, the grease container which stored grease inside is provided in the back side of the angular ball bearing located in the rear end side of the spindle, and the inner circumference of the outer ring or next to the outer ring, A spindle device provided with a gap forming piece that forms a gap for allowing the base oil of the grease in the grease container to ooze out in the vicinity of the raceway surface of the outer ring.   The gap forming piece of the grease container provided on the angular ball bearing located at least on the front end side of the spindle among the plurality of angular ball bearings according to claim 2, A spindle device that supplies the base oil of the grease in the axial direction.   The gap forming piece of the grease container provided for the angular ball bearing positioned at least on the front end side of the spindle among the plurality of angular ball bearings according to claim 3 extends in an axial direction, A spindle device in which the tip portion faces the inner peripheral surface portion adjacent to the raceway surface through the gap.   The annular inclined oil guide surface according to claim 4, wherein an inner peripheral surface portion adjacent to the raceway surface of the outer ring is inclined along the edge of the raceway surface so as to approach the bottom of the raceway surface as the raceway surface is approached. And a cylindrical surface portion continuing from the inclined oil guide surface to the opposite side of the raceway surface, and forming the gap between the cylindrical surface portion and the gap forming piece.   6. The spindle device according to claim 5, wherein the gap forming piece extends to a part of the inclined oil guide surface.   7. The spindle device according to claim 2, wherein a grease container for each of the angular ball bearings is provided on an inner periphery of the outer ring.   7. The spindle device according to claim 2, wherein a grease container for each angular ball bearing is provided on an inner periphery of an outer ring spacer adjacent to the outer ring.   9. The angular ball bearing according to claim 2, wherein a plurality of the angular ball bearings are installed side by side on the front end side of the spindle and a plurality of the front side faces the front end side of the spindle. A plurality of spindle devices are arranged side by side on the rear end side of the spindle, with the front side facing the rear end side of the spindle.   10. The spindle device according to claim 2, wherein the spindle is installed in a horizontal posture.   10. The spindle device according to claim 2, wherein the spindle is installed in a standing posture with a front end facing downward.

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