JP5845652B2 - Bearing device and spindle device for machine tool - Google Patents

Description

  The present invention relates to a bearing device and a spindle device for a machine tool, and more particularly, to a bearing device and a machine including a rolling bearing that is grease-lubricated by a small amount of grease supply in a spindle or a high-speed motor of a machine tool that rotates at high speed. The present invention relates to a machine spindle device.

  A rolling bearing used for a spindle device of a machine tool is required to have high performance with respect to characteristics such as vibration and sound in order to improve machining accuracy as well as high-speed rotation and long life. For lubrication of such a rolling bearing, grease lubrication that is easy to handle and advantageous in terms of environment and cost is employed.

  Conventionally, as a grease-lubricated rolling bearing, one that is lubricated only with grease enclosed in an initial stage is used so as not to generate heat. In addition, when rotating at high speed without performing the grease break-in operation at the initial stage when the grease is filled, abnormal heat generation occurs due to the biting of the grease and stirring resistance. It is in a state.

Further, in recent years, the speed of machine tool spindles has been increased, and the rolling bearings supporting the spindles have an environment of dmN (= (bearing inner diameter + bearing outer diameter) ÷ 2 × rotational speed (rpm)) of 1 million or more. It is not rare to be used. Grease-lubricated rolling bearings tend to have a shorter life at high speeds than oil-lubricated ones such as oil-air and oil mist. For this reason, recently, a method of replenishing grease while the rolling bearing is rotating has been adopted. However, in a rolling bearing used at high speed rotation, if the amount of grease replenished is large, the oil content of excess grease at the time of lubrication is stirred at the rolling contact portion, and abnormal heat generation is likely to occur. In particular, in the case of a cylindrical roller bearing, since the contact portion between the raceway surface and the rolling element is a line contact, heat is easily generated as compared with a point contact ball bearing, and the replenishment amount per time is 0.005 to 0.00. 1 cm ^3, preferably, it is necessary to replenish the grease traces of 0.005~0.02cm ^3.

  Conventionally, as a grease-lubricated bearing device, grease is supplied from the bearing inner ring side via an outer ring spacer so as to prevent excessive supply of grease and suppress heat generation due to grease stirring resistance. A rolling bearing device is disclosed (for example, see Patent Document 1).

  Further, in the bearing device described in Patent Document 2, in the cylindrical roller bearing, a replenishment hole having a diameter of 0.1 to 5 mm that opens toward the outer peripheral surface of the annular portion of the cage is formed in the outer ring. It is described that the total amount of grease replenished is regulated to prevent a large amount of grease from being supplied to the bearing space, thereby preventing temperature pulsation and abnormal temperature rise due to grease biting and stirring resistance. In addition, a plurality of concave notches are formed in the circumferential direction on the outer peripheral surface of the annular portion of the cage, and excess grease is discharged from the bearing space to the outside through the concave notches, and between the concave notches. It is described that the grease is evenly conditioned by the guide protrusions to prevent abnormal temperature rise when replenishing grease.

JP 2001-271843 A JP 2008-121888 A

  By the way, the bearing device described in Patent Document 1 is a technique based on the premise of supplying a large amount of grease, and when grease is supplied to the rolling bearing, excess grease is discharged out of the bearing and the grease is stirred. There was a problem that the heat consumption was suppressed and the grease consumption increased.

  On the other hand, in the bearing device described in Patent Document 2, it is disclosed that the amount of grease replenished per time is restricted in order to prevent abnormal temperature rise during replenishment of grease during rotation. If it is reduced, the grease will stay in the grease supply path for a long time, the grease base oil will be separated, and the separated base oil will leak from the mating part, causing it to solidify in the grease supply path. There is a possibility that the grease cannot be reliably supplied.

  Further, in the bearing device described in Patent Document 2, the guide gap between the inner peripheral surface of the outer ring and the guide surface of the cage and the axial position of the supply hole are not specifically defined.

  The present invention has been made in view of the above-described problems. The purpose of the present invention is to stably supply grease even in grease lubrication in which a small amount of grease is supplied. An object of the present invention is to provide a bearing device and a spindle device for a machine tool that can prevent abnormal temperature rise caused by it and achieve a long life.

The above object of the present invention can be achieved by the following constitution.
(1) a cylindrical roller bearing having an outer ring formed with at least one supply hole penetrating in the radial direction, and a cage guided by the outer ring;
A housing in which at least one greasing hole that is opened in an inner peripheral surface to which the outer ring is fitted is formed;
A bearing device in which the cylindrical roller bearing is grease lubricated by grease supplied through the grease supply hole and the supply hole,
A circumferential groove is formed on the inner peripheral surface of the housing or the outer peripheral surface of the outer ring so that the grease supply hole and the replenishment hole communicate with each other.
The hole diameter of the greasing hole and the replenishing hole is 1.5 mm or more and 10 mm or less,
The guide clearance between the guide surface formed on the outer peripheral surface of the cage and the inner peripheral surface of the outer ring facing the guide surface is set to 0.2 to 1.0 mm in diameter, and
The axially inner end in the opening of the supply holes, as well as positioned on the end surface nearer Te axially odor with respect to the axial direction inside end of the guide surface of the cage, the axial outer end of the guide surface of the retainer located in orbital plane closer Te axially odor relative,
The guide surface of the cage is composed of a flat guide portion formed on the axially inner end side and a curved portion formed on the axially outer end side,
The bearing device according to claim 1, wherein an opening of the supply hole is at a position facing at least a curved portion of the guide surface in the axial direction .
(2) The flat guide portion of the cage is provided at a predetermined interval in the circumferential direction on the outer circumferential surface of the annular portion of the cage having a uniform outer diameter or on the annular portion of the cage. The bearing device according to (1), which is configured by an outer peripheral surface of the guide projection piece.
( 3 ) The bearing device according to (1) or (2) above, wherein a supply amount of the grease supplied to the cylindrical roller bearing is 0.005 to 0.02 cm ³ .
(3) A spindle device for a machine tool comprising the bearing device according to any one of (1) to (3) .

According to the bearing device of the present invention, the replenishment hole formed in the outer ring and the greasing hole formed in the housing are communicated by a circumferential groove formed in the inner peripheral surface of the housing or the outer peripheral surface of the outer ring, The diameters of the supply hole and the greasing hole are set to 1.5 mm or more and 10 mm or less. Further, the guide gap formed between the guide surface formed on the outer peripheral surface of the cage and the inner peripheral surface of the outer ring facing the guide surface is set to 0.2 to 1.0 mm in diameter, and the opening of the supply hole the axially inner end in the parts, as well located on the end face closer Te axially odor with respect to the axial direction inside end of the guide surface of the cage, Te axially odor with respect to the axial direction outer end of the guide surface of the cage located in orbital plane closer, the guide surface of the cage is constituted by a flat guide portion formed axially inner end side, a bending portion formed in the axially outer end side, the opening of the supply hole The portion is at a position facing at least the curved portion of the guide surface in the axial direction . Accordingly, the lubricated grease is stretched into a thin film with rotation while lubricating the guide surface, and the grease base oil component is gradually supplied to the rolling contact portion through the outer ring raceway surface. As a result, even in grease lubrication in which a small amount of grease is supplied, grease can be supplied stably, and abnormal temperature rise due to the stirring resistance of the grease can be prevented, and the bearing device has a long service life. can do.

Further, since the amount of grease supplied to the rolling bearing per one time is 0.005 to 0.02 cm ³ , the occurrence of abnormal heat generation and temperature pulsation caused by the stirring resistance of the grease can be suppressed and stable. High speed rotation is possible.

Further, according to the spindle device for machine tools of the present invention, the spindle is supported by the bearing device lubricated with a very small amount of grease having a supply amount of 0.005 to 0.02 cm ³ per one time. There is no abnormal heat generation or temperature pulsation due to resistance, and high-precision machining is possible.
Further, by adopting the grease replenishment method of the present invention, abnormal heat generation and temperature pulsation do not occur even when replenishing not only when the bearing is stopped but also during rotation of the bearing.

It is a longitudinal cross-sectional view of the spindle apparatus for machine tools with which the bearing apparatus which concerns on 1st Embodiment of this invention is applied. It is a principal part enlarged view of the front side bearing vicinity of the main spindle apparatus for machine tools shown in FIG. It is a principal part enlarged view of the rear side bearing vicinity of the main spindle apparatus for machine tools shown in FIG. It is a perspective view which shows the holder | retainer used for the cylindrical roller bearing of FIG. (A) And (b) is a principal part expanded sectional view for demonstrating the position of the replenishment hole of this embodiment. (A) And (b) is a principal part expanded sectional view for demonstrating the position of the replenishment hole as a comparative example. It is a perspective view which shows the modification of the holder | retainer used for a cylindrical roller bearing. It is sectional drawing of the cylindrical roller bearing to which the cage of FIG. 7 was applied. It is a perspective view which shows the other modification of the holder | retainer used for a cylindrical roller bearing. FIG. 10 is a cross-sectional view of a cylindrical roller bearing to which the cage of FIG. 9 is applied. It is a whole block diagram of a bearing apparatus evaluation test machine. It is a table | surface which shows the presence or absence of the pulsation at the time of supplying grease to each holder | retainer of conditions AG which changed the position of the supply hole, and each holder | retainer. It is a graph which shows the durable time in the grease replenishment test using the holder | retainer of conditions AG of FIG.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a bearing device according to the present invention and a spindle device for a machine tool using the same will be described below in detail with reference to the drawings.

(First embodiment)
FIG. 1 is a longitudinal sectional view of a spindle device for a machine tool to which a bearing device of the present invention is applied. As shown in FIG. 1, the main shaft 101 of the main shaft device 100 is supported in the main shaft housing 103 by an angular ball bearing 40 and a cylindrical roller bearing 20 which are rolling bearings.

  The spindle housing 103 includes a housing main body 104, a front bearing housing 105 that is fitted and fixed to the front end (left side in the figure) of the housing main body 104, and a rear side (right side in the figure) that is fitted and fixed to the rear side of the housing main body 104. Side bearing housing 106. An outer ring pressing member 107 and an inner ring pressing member 108 are provided at the end of the front bearing housing 105, and a labyrinth is formed between the outer ring pressing member 107 and the inner ring pressing member 108. A rear end surface of the spindle housing 103 is covered with a cover 109.

  As shown in FIG. 2, the four angular ball bearings 40 fitted into the front bearing housing 105 are arranged so as to roll freely with a contact angle between the outer ring 41, the inner ring 42, the outer ring 41, and the inner ring 42. A plurality of balls 43 as a moving body and a holder 44 that holds the balls 43 at equal intervals in the circumferential direction are provided. Further, as shown in FIG. 3, one cylindrical roller bearing 20 fitted in the rear bearing housing 106 is also used as a rolling element that is disposed between the outer ring 21, the inner ring 22, the outer ring 21, and the inner ring 22 so as to freely roll. A plurality of rollers 23 and a cage 24 (see FIG. 4) for holding the rollers 23 at equal intervals in the circumferential direction are provided. An outer ring spacer 110 is disposed between the outer rings 41 of the four angular ball bearings 40, and an inner ring spacer 111 is disposed between the inner rings 42. Further, an outer ring spacer 112 is also arranged on one side of the cylindrical roller bearing 20 in the axial direction of the outer ring 21, and an inner ring spacer 113 is also arranged on both sides of the inner ring 22 in the axial direction. In the present embodiment, the angular ball bearing 40 and the front bearing housing 105, and the cylindrical roller bearing 20 and the rear bearing housing 106 constitute the bearing device of the present invention.

  A rotor 120 is fitted and fixed to a substantially central portion of the main shaft 101 in the axial direction. On the outer peripheral surface side of the rotor 120, a stator 121 is coaxially arranged with a predetermined distance. The stator 121 is fixed to the housing main body 104 via a stator fixing member 122 disposed on the outer peripheral surface side of the stator 121. A plurality of grooves 123 are formed between the housing body 104 and the stator fixing member 122 in a direction along the circumferential direction of the main shaft 101. A coolant for cooling the stator 121 flows in the plurality of grooves 123.

  Similarly, a plurality of grooves between the front bearing housing 105 and the cooling sleeve 125 that fits outside the housing 105 and on the outer peripheral side of the angular ball bearing 40 are passed through the housing and bearing cooling refrigerant. 124 is formed.

  A plurality of grease supply ports 132 for supplying grease for supplying grease to each of the rolling bearings 40 and 20 are opened along the circumferential direction on the rear end surface of the spindle housing 103 (see FIG. 1). Only one is shown). The plurality of grease supply ports 132 communicate with a plurality of grease supply paths 133a to 133f formed in the housing body 104, the front bearing housing 105, and the rear bearing housing 106, respectively (in FIG. (The grease supply paths 133a to 133f are shown in the same cross section). Thereby, the spindle device 100 according to the present embodiment supplies grease into the spindle housing 103 via the grease supply pipe 131 from the grease replenisher 130 provided outside.

  The grease supply paths 133a and 133b are opened on the inner peripheral surface to which the outer ring 21 of the cylindrical roller bearing 20 is fitted, and the grease supply paths 133c to 133f are inner circumferences to which the outer rings 41 of the respective angular ball bearings 40 are fitted. Open to the surface. The grease supply paths 133a to 133f communicate with supply holes 47 and 27 formed in the outer rings 41 and 21 of the bearings 40 and 20 via circumferential grooves 46 and 26, which will be described later. As a result, the grease supplied from the grease replenisher 130 is independently supplied into the bearing spaces of the bearings 40 and 20 through the replenishing holes 47 and 27.

  The grease replenisher 130 is configured to be able to supply grease independently to the bearings 40 and 20. That is, the grease replenisher 130 performs grease shot on each of the bearings 40 and 20 at an appropriate timing (intermittently or periodically). The replenished grease becomes familiar with the entire interior of the bearings 40 and 20 along with the rolling of the balls 43 inside the angular ball bearing 40 and the cylindrical rollers 23 inside the cylindrical roller bearing 20, and compensates for the insufficient grease. Since the cylindrical roller bearing 20 is more prone to temperature pulsation than the angular ball bearing 40, it is better that the replenishment amount per time is smaller than the replenishment amount to the angular ball bearing.

  As shown in FIGS. 3 and 4, the diameter d1 of the greasing hole 13 formed in the rear bearing housing 106 constituting the grease supply passages 133a and 133b for supplying grease to the cylindrical roller bearing 20 is 1 .5 mm to 10 mm, preferably 1.5 mm to 7 mm.

  In addition, two supply holes 27 are formed in the outer ring 21 of the cylindrical roller bearing 20 so as to penetrate the inner and outer peripheral surfaces of the outer ring 21 in the radial direction. Are formed with two circumferential grooves 26. The hole diameter d2 of each supply hole 27 is also set to 1.5 mm or more and 10 mm or less, preferably 1.5 mm or more and 7 mm or less.

  The circumferential groove 26 has a width wider than the hole diameter d2 of the replenishing hole 27, and its cross-sectional area is preferably larger than the cross-sectional area of the replenishing hole 27 from the viewpoint of ensuring the fluidity of the grease. The circumferential groove 26 is a groove for allowing the greasing hole 13 and the supply hole 27 to communicate with each other, and may be formed on the inner circumferential surface of the housing 106.

  As shown in FIG. 4, the outer ring guide type resin cage 24 of the cylindrical roller bearing 20 includes a pair of annular portions 31 and a plurality of column portions 32 that connect the pair of annular portions 31 in the axial direction. A plurality of pocket portions 33 that respectively hold the plurality of cylindrical rollers 23 rotatably are formed. Further, a roller stopper 34 for reliably holding the cylindrical roller 23 is provided at the axially intermediate portion on both sides in the circumferential direction of the column portion 32 so as to protrude from the radially outer surface of the column portion 32. .

  A plurality of concave cutouts 35 are formed on the outer circumferential surface of the annular part 31 of the cage 24 so as to be spaced apart in the circumferential direction. Therefore, the annular part 31 has a gap between adjacent concave cutouts 35. A plurality of guide protrusions 36 each projecting in the radial direction are formed. In addition, the guide protrusions 36 of one annular part 31 and the guide protrusions 36 of the other annular part 31 are arranged in a zigzag pattern alternately on the left and right sides in the circumferential direction, respectively, and predetermined in the circumferential direction. Are provided at intervals.

  Further, as shown in FIGS. 5A and 5B, a guide gap g having a diameter gap of 0.2 to 1.0 mm is provided between the outer peripheral surface of the guide protrusion 36 and the inner peripheral surface of the outer ring 21. Is formed, and the outer peripheral surface of the guide protrusion 36 is in sliding contact with the inner peripheral surface of the outer ring 21 to constitute a guide surface 37 that guides the cage 24.

  In addition, with respect to the cage 24 formed in this way, the axial inner end 27a at the opening of the supply hole 27 coincides with the axial inner end 37a of the guide surface 37 of the cage 24 in the axial direction or It is located closer to the end surface (see FIG. 5A) and coincides in the axial direction with respect to the axially outer end 37b of the guide surface 37 of the cage 24 or is located closer to the track surface (see FIG. 5B). .

  With this configuration, a part of the grease supplied from the replenishment hole 27 of the outer ring 21 adheres to the guide surface 37 of the cage 24, lubricates the guide surface 37, and rotates with the cage 24. Between the guide surface 37 and the inner peripheral surface of the outer ring 21. Then, the grease base oil component gradually moves along the guide gap g and is finally supplied to the rolling contact portion. Further, the concave notch 35 acts to discharge excess grease in the bearing space to the outside.

  On the other hand, as shown in FIG. 6A, the axially inner end 27 a at the opening of the supply hole 27 is closer to the track surface in the axial direction than the axially inner end 37 a of the guide surface 37 of the cage 24. In this case, grease with a certain volume is directly supplied to the outer ring raceway surface, resulting in a large stirring resistance during rotation and an instantaneous abnormal temperature rise (impulse pulsation). End up. Further, as shown in FIG. 6B, the axially inner end 27 a at the opening of the supply hole 27 is closer to the end surface in the axial direction than the axially outer end 37 b of the guide surface 37 of the cage 24. In this case, the grease does not adhere to the guide surface 37 of the cage 24, and it is difficult for the grease to reach the rolling contact portion.

  Further, in the same circumferential position, the cage 24 has a guide gap g / 2 formed between the guide surface 37 of the guide projection piece 36 and the inner peripheral surface of the outer ring 21 in one annular portion 31. On the other hand, in the other annular portion 31, a gap G / 2 (G is a diameter gap) is formed between the outer peripheral surface of the concave notch 35 and the inner peripheral surface of the outer ring 21. For this reason, lubricating oil can be smoothly discharged from the gap G, and the difference in size between the gap g and the gap G causes a pressure difference between the two annular portions 31 to cause air convection, thereby causing convection action. This facilitates the discharge of the lubricant. Therefore, abnormal temperature rise during high-speed rotation can be suppressed, and the running-in time can be shortened even when grease lubrication is performed.

  As shown in FIG. 2, the configuration for supplying grease to each angular ball bearing 40 is substantially the same as that of the cylindrical roller bearing 20. That is, the hole diameter d1 of the greasing hole 13 formed in the front bearing housing 105 that constitutes the grease supply paths 133c to 133f is set to 1.5 mm to 10 mm, preferably 1.5 mm to 7 mm.

  Further, the outer ring 41 of the angular ball bearing 40 has a supply hole 47 whose hole diameter d2 is set to 1.5 mm or more and 10 mm or less, preferably 1.5 mm or more and 7 mm or less, penetrating the inner and outer peripheral surfaces of the outer ring 41 in the radial direction. Is formed. Furthermore, a circumferential groove 46 having a width wider than the hole diameter d2 of the supply hole 47 and having a cross-sectional area larger than the cross-sectional area of the supply hole 47 is formed on the outer peripheral surface of the axial position including the supply hole 47. .

  Also in this case, a guide gap g having a diameter gap of 0.2 to 1.0 mm is formed between the outer circumferential surface of the cage 44 and the inner circumferential surface of the outer ring 21, and the outer circumferential surface of the cage 44 is A guide surface 48 for guiding the cage 44 is configured by sliding contact with the inner peripheral surface of the outer ring 21.

  Further, in the cage 44 formed in this way, the axially inner end 47a of the supply hole 47 is aligned with or close to the end surface in the axial direction with respect to the axially inner end 48a of the guide surface 48 of the cage 44. At the same time, it is aligned in the axial direction with respect to the axially outer end 48b of the guide surface 48 of the cage 44 or is positioned closer to the track surface.

In the spindle device for a machine tool configured as described above, the grease supply amount per one time is 0.005 to 0.00 in order to achieve prevention of temperature rise due to grease stirring resistance and high vibration characteristics and acoustic characteristics. 1 cm ^3, preferably, it is lubricated by the trace amount of grease 0.005~0.02cm ^3. In addition, as the target grease, in the case of a bearing for a machine tool spindle device, a temperature rise is suppressed and low torque is required, so the consistency is No. 2 or No. 3 (JIS K2220 5.3). ), A base oil viscosity of 15 to 120 mm ² / S (40 ° C.) is selected.

If the amount of grease supplied per lubrication is lubricated with a very small amount of grease of 0.005 to 0.1 cm ³ , the time for the grease to stay in the lubrication path becomes longer, and the base oil and increase due to secular change are increased. The agent is separated from the grease and solidifies in the greasing route, and the fluidity of the grease decreases, and the flow resistance (friction resistance between the grease and the inner wall of the greasing route) increases due to the solidification of the grease. You may not be able to lubricate.

  The reason why the diameters d1 and d2 of the greasing hole 13 and the replenishing hole 27 are 1.5 mm or more and 10 mm or less is that when the hole diameters d1 and d2 are 1.5 mm or less, the grease solidifies due to secular change (decrease in fluidity). This is because it becomes difficult to stably supply grease due to an increase in flow resistance.

  Further, if the hole diameters d1 and d2 are set to 10 mm or more, it is substantially difficult to arrange the two greasing holes 13 and the replenishing holes 27 side by side in the same phase in the axial direction. That is, the smallest rolling bearing generally used for a machine tool spindle device has an inner diameter of about 30 mm, and the hole diameter is preferably 10 mm or less, and preferably about 7 mm. Further, when the hole diameter d1 of the greasing hole 13 is large, when a chamfered portion is formed at the end of the outer peripheral surface of the outer ring 21, grease, in particular, the base oil content in the grease is removed from the gap between the greasing hole 13 and the chamfered portion. There is a risk of leakage, which is not preferable.

  As described above, according to the bearing device including the cylindrical roller bearing 20 and the rear bearing housing 106 or the bearing device including the angular ball bearing 40 and the front bearing housing 105, the replenishment formed on the outer rings 21 and 41. The greasing hole 13 formed in the hole 47 and the housings 105 and 106 is connected by a circumferential groove 46 formed on the inner peripheral surface of the housing 105 or 106 or the outer peripheral surface of the outer ring 41. The diameters d1 and d2 of the oil holes 13 are set to 1.5 mm or more and 10 mm or less. Further, the guide gap g between the guide surface 37 of the cage 24 and the inner peripheral surface of the outer ring 21 facing the guide surface 37 is set to 0.2 to 1.0 mm in diameter, and the replenishment hole 27 is opened. The axial inner end 27a of the guide portion is coincident with or closer to the end surface in the axial direction with respect to the axial inner end 37a of the guide surface 37 of the cage 24, and the axial outer end 37b of the guide surface 37 of the cage 24. In the axial direction or closer to the track surface. Accordingly, the lubricated grease is stretched into a thin film with rotation while lubricating the guide surface 37, and the grease base oil component is gradually supplied to the rolling contact portion through the outer ring raceway surface. As a result, even in grease lubrication in which a small amount of grease is supplied, grease can be supplied stably, and abnormal temperature rise due to the stirring resistance of the grease can be prevented, and the bearing device has a long service life. can do.

  In addition, this invention is not limited to each embodiment and modification which were mentioned above, A deformation | transformation, improvement, etc. are possible suitably.

  For example, the cage 24 of the cylindrical roller bearing 20 may have a configuration in which the outer peripheral surfaces of the pair of annular portions 31 have a uniform outer diameter, as shown in FIGS. 7 and 8. As shown in FIG. 4, the guide protrusions 36 of the pair of annular portions 31 may be provided at the same phase and at a predetermined interval in the circumferential direction. In any case, the guide gap g between the guide surface 37 of the cage 24 and the inner peripheral surface of the outer ring 21 facing the guide surface 37 is set to 0.2 to 1.0 mm in diameter, and The axially inner end 27 a of the opening of the replenishing hole 27 coincides with or is closer to the end surface in the axial direction than the axially inner end 37 a of the guide surface 37 of the retainer 24, and the guide surface 37 of the retainer 24. Is aligned with the axial outer end 37b in the axial direction or positioned closer to the track surface.

  The replenishment hole 27 may be any as long as the axially inner end 27a of the opening that opens into the bearing space has the above positional relationship with the guide surface 37 of the cage 24. The shape may be inclined as long as it penetrates through.

  In the above description, the bearing device of the present invention has been described as being applied to a cylindrical roller bearing and a ball bearing. However, the present invention is not limited to this and can be applied to any type of rolling bearing that is grease lubricated. Have the same effect.

  Furthermore, although the case where the bearing device of the present invention is applied to a machine tool spindle device has been described in the present embodiment, it can also be applied to a high-speed motor.

  In order to confirm the effect of the present invention, cylindrical roller bearings having different replenishment hole positions were incorporated in a bearing device evaluation tester shown in FIG.

  As shown in FIG. 11, in the bearing device evaluation test machine 200, the rotating shaft 202 is rotatably supported by a pair of ball bearings 203 and 203 and a sample cylindrical roller bearing 205 fitted in the housing 201.

The housing 201 is provided with a greasing hole 204 having a hole diameter d1 of 3.0 mm, while a supply hole having a hole diameter d2 of 1.5 mm is provided in the outer ring of the cylindrical roller bearing 205 and is arranged outside. In addition, 0.01 cm ³ of grease per shot is supplied every 6 hours from a grease replenishing device (not shown). The grease used had a base oil viscosity of 20 mm ² / S (40 ° C.) and a consistency of No. 2 (JIS K2220 5.3).

  Each of the sample roller bearings 205 is a single row cylindrical roller bearing with a nominal number N1012 (inner diameter 60 mm, outer diameter 95 mm, width 18 mm), a radial clearance of 0 μm at the time of assembly, and a driving method of the rotating shaft 202 is a belt drive. The test was conducted without cooling.

  When the grease was replenished under the above conditions, the position of the axially inner end 27a in the opening of the replenishing hole 27 was positioned closer to the raceway surface in the axial direction than the axially inner end of the guide surface 37 of the cage 24. In addition, in the cylindrical roller bearing 20 of the condition A, a phenomenon in which the temperature rise value of the bearing outer ring pulsates appeared along with the timing of lubrication (see FIG. 12). This is because the agitation resistance is increased due to the protrusion and the supply directly into the bearing. Further, after about 100 hours of endurance time, abnormal heat generation due to excessive supply amount occurred.

  Further, in the cylindrical roller bearing 20 of the condition G, the axially inner end 27a in the opening of the supply hole 27 is positioned closer to the end surface in the axial direction than the axially outer end 37b of the guide surface 37 of the cage 24. After approximately 1000 hours of durability time, seizure occurred. This is due to insufficient lubrication in the bearing and poor lubrication.

On the other hand, the axially inner end 27a in the opening of the replenishing hole 27 coincides with or is closer to the end surface in the axial direction than the axially inner end 37a of the guide surface 37 of the retainer 24, and the guide surface of the retainer 24. The cylindrical roller bearings 20 under the conditions B to F, which coincide with the axial outer end 37b of the shaft 37 in the axial direction or are located closer to the raceway surface, all have a durability time exceeding 5000 hours. Since the pulsation phenomenon in which the temperature rises does not occur, it can be understood that the grease is properly supplied into the bearing.
Moreover, although the above result is a case where the cage in which the guide protrusions 36 shown in FIG. 4 are arranged in a staggered manner, the same result can be obtained also in the cage shown in FIGS. However, I was able to confirm.

13 Greasing hole 20 Cylindrical roller bearing (rolling bearing)
21, 41 Outer rings 24, 44 Cage 26, 46 Circumferential grooves 27, 47 Supply holes 37, 48 Guide surface 40 Angular contact ball bearing (rolling bearing)
100 Spindle device for machine tool 105 Front bearing housing (housing)
106 Rear bearing housing (housing)
d1 Greasing hole diameter d2 Replenishing hole diameter

Claims (4)

A cylindrical roller bearing having an outer ring formed with at least one supply hole penetrating in the radial direction, and a cage guided by the outer ring;
A housing in which at least one greasing hole that is opened in an inner peripheral surface to which the outer ring is fitted is formed;
A bearing device in which the cylindrical roller bearing is grease lubricated by grease supplied through the grease supply hole and the supply hole,
A circumferential groove is formed on the inner peripheral surface of the housing or the outer peripheral surface of the outer ring so that the grease supply hole and the replenishment hole communicate with each other.
The hole diameter of the greasing hole and the replenishing hole is 1.5 mm or more and 10 mm or less,
The guide clearance between the guide surface formed on the outer peripheral surface of the cage and the inner peripheral surface of the outer ring facing the guide surface is set to 0.2 to 1.0 mm in diameter, and
The axially inner end in the opening of the supply holes, as well as positioned on the end surface nearer Te axially odor with respect to the axial direction inside end of the guide surface of the cage, the axial outer end of the guide surface of the retainer located in orbital plane closer Te axially odor relative,
The guide surface of the cage is composed of a flat guide portion formed on the axially inner end side and a curved portion formed on the axially outer end side,
The bearing device according to claim 1, wherein an opening of the supply hole is at a position facing at least a curved portion of the guide surface in the axial direction . The flat guide portion of the cage has an outer peripheral surface of the annular portion of the cage having a uniform outer diameter, or guide protrusions provided at predetermined intervals in the circumferential direction on the annular portion of the cage. The bearing device according to claim 1, which is configured by an outer peripheral surface of a piece. Supply amount per the grease supplied to the cylindrical roller bearing, a bearing device according to claim 1 or 2, characterized in that a 0.005~0.02cm ^3. A spindle device for a machine tool comprising the bearing device according to any one of claims 1 to 3 .

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