JP2011133000A - Cylindrical roller bearing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cylindrical roller bearing device which reduces the manufacturing cost of a constitutive component such as a bearing ring, and provides a high-speed bearing. <P>SOLUTION: This cylindrical roller bearing device includes a cylindrical roller bearing 1 interposed with a plurality of cylindrical rollers 5 held by an annular retainer 6, between raceway surfaces 4a, 2a of inner and outer rings 4, 2, and a nozzle member 3 provided adjacent to axial-directional both sides of the outer ring 2 for delivering a lubricant into a bearing space between the inner and outer rings 4, 2. The inner ring 4 is constituted to have no flange part, the nozzle part 3 is provided with an annular flange part 8 inserted into the bearing space and having a nozzle hole 8a for the lubricant, and the tip face of the flange part 8 is made to serve as a roller guide face 8c for guiding the end face of each cylindrical roller 5. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a cylindrical roller bearing used for a main shaft of a machine tool, for example, and relates to a technique that focuses on ease of bearing processing and reduction in the number of components while maintaining a conventional bearing function.

  In general, angular ball bearings and cylindrical roller bearings are often used in combination on the spindle of a machine tool. These bearings are required to have rigidity for ensuring the processing accuracy of the product and high speed for improving processing efficiency. Angular contact ball bearings are excellent in high speed performance, but are inferior to cylindrical roller bearings in terms of rigidity. On the other hand, although the cylindrical roller bearing is excellent in rigidity, it is inferior in high-speed performance compared with the angular ball bearing. That is, in order to achieve both high rigidity and high speed of the main shaft, it is indispensable to increase the speed of the cylindrical roller bearing used in combination with the angular ball bearing.

As a main factor hindering the high speed of cylindrical roller bearings,
(1) Increase in preload due to inner ring expansion (due to temperature rise and centrifugal force) during operation,
(2) Lubrication of the flange portion and the cage guide portion that are in sliding contact with the roller end surface;
There are two possible points. The present applicant has proposed an improved technique (Patent Document 1) for such an obstruction factor.

  The cylindrical roller bearing which is an object of this improved technology has a so-called N-type structure having a roller guide collar on the inner ring side. In the detailed configuration, positioning spacers for the outer ring are arranged on both sides of the outer ring, and a nozzle member for discharging a lubricant is provided separately from the positioning spacer on the inner diameter side of each positioning spacer. The inner diameter surface of the cage is guided by the outer diameter surface of the nozzle member. Adopting this guide system is effective for securing lubricating oil on the guide surface and stabilizing the cage behavior. In addition, for the purpose of speeding up the bearing, a technique is also disclosed in which an inner ring made of ceramics is applied and the amount of expansion of the inner ring during operation can be suppressed.

Japanese Patent Application No. 2008-162439

As technical elements for operating the cylindrical roller bearing at a high speed, it is important to suppress an increase in preload due to the expansion of the inner ring during operation and to reliably supply the lubricating oil to a place where the lubricating oil is required.
The cylindrical roller bearing having a roller guide flange on the inner ring side has an N-shaped structure that complicates the inner ring shape. Therefore, the molding itself is not easy and the machining after the molding takes time. This increases the manufacturing cost. In order to reduce the manufacturing cost, it is conceivable to use a so-called NU type structure without a collar portion that can simplify the inner ring shape. However, the NU type structure has a collar portion on the outer ring side. In this case, it may cause heat generation due to oil retention in the outer ring raceway. Such heat generation due to oil retention leads to a high bearing temperature, which leads to a decrease in machining accuracy in machine tool spindle applications.

  An object of the present invention is to provide a cylindrical roller bearing device capable of reducing the manufacturing cost of components such as a bearing ring and increasing the speed of the bearing.

  The cylindrical roller bearing device according to the present invention is provided adjacent to both sides of the outer ring in the axial direction, and a cylindrical roller bearing in which a plurality of cylindrical rollers held by an annular cage are interposed between the raceway surfaces of the inner and outer rings. A cylindrical roller bearing device including a nozzle member for discharging a lubricant into a bearing space between the inner and outer rings, wherein the inner ring and the outer ring have no collar portion, and the nozzle member is inserted into the bearing space and is a nozzle for the lubricant An annular flange having a hole is provided, and a tip end surface of the flange is disposed on the inner ring side or the outer ring side to serve as a roller guide surface that guides the end surface of the cylindrical roller.

According to this configuration, during the bearing operation, the end surface of the cylindrical roller is guided to the front end surface of the collar portion of the nozzle member disposed on both axial sides of the outer ring. Thus, since the tip end surface of the collar portion of the nozzle member is a roller guide surface that guides the end surface of the cylindrical roller, there is no need to provide a collar portion for guiding the cylindrical roller on the inner and outer rings. Therefore, the shape of the inner and outer rings can be simplified from that of the prior art. In particular, since the inner ring has no collar portion, the inner ring can be easily formed, and the number of processes such as machining after the inner ring can be reduced. Therefore, the inner ring can be manufactured using various materials having a lower linear expansion coefficient and a lower density than general bearing steel. A bearing using an inner ring made of such a material can increase the speed of the bearing.
In addition, by using the roller guide surface as the front end surface of the collar portion, it is possible to eliminate the outer ring collar portion. In this case, the manufacturing cost can be further reduced. In addition, since the outer ring raceway portion does not have a brim that becomes an obstacle to oil discharge, the oil can be easily discharged from the bearing. As a result, oil stagnation in the raceway portion of the outer ring can be suppressed, and problems such as heat generation due to oil stagnation can be solved. Thereby, in the machine tool spindle application, the machining accuracy can be maintained with high accuracy.

  Outer ring positioning spacers may be arranged on both sides in the axial direction of the outer ring, and the nozzle member may be integrally provided on the inner peripheral side portion of each outer ring positioning spacer. In this case, the number of parts can be reduced, and the structure of the cylindrical roller bearing device can be simplified. In this case, the number of assembling steps can be reduced as compared with the nozzle member provided separately from the outer ring positioning spacer.

  Provided on the outer diameter surface of the inner ring is a slope portion having a large diameter on the raceway surface, and the nozzle hole provided in the flange portion of the nozzle member discharges the lubricant toward the slope portion of the inner ring. Also good. In this case, the lubricant discharged from the nozzle hole toward the inclined surface portion of the inner ring is guided into the bearing while adhering to the inclined surface portion of the inner ring due to the centrifugal force and surface tension caused by the rotation of the inner ring. Thus, the lubricant can be smoothly introduced into the bearing.

  The inner diameter surface or the outer diameter surface of the flange may be a cage guide surface that guides the peripheral surface of the cage. In this case, it is possible to solve the problems that the swinging of the cage increases and the cage pocket holding the cylindrical roller is damaged due to interference with the cylindrical roller. In this case, the cage guide method has a lower sliding speed on the guide surface than the outer ring guide method, so that the bearing power loss is reduced, the bearing temperature can be suppressed, and this is advantageous in terms of preload management.

  You may provide the clearance angle with respect to the end surface of the said cylindrical roller in the front end surface of the said collar part so that an outer diameter side may leave | separate from the end surface of the said cylindrical roller. In this case, by using the clearance angle corresponding to irregular motion such as skew and dance that can occur during the operation of the bearing, abnormal contact between the end surface of the cylindrical roller and the distal end surface of the collar portion due to the occurrence of irregular motion is avoided. be able to.

  A heat treatment may be applied to at least a portion of the flange portion of the nozzle member that serves as a guide surface. Since the guide surface of the collar portion of the nozzle member slides while in contact with the bearing during operation, it is necessary to consider wear resistance and the like. Since the heat treatment is performed on at least a portion of the flange portion that becomes the guide surface, the surface hardness of the guide surface of the flange portion can be made higher than that before the heat treatment. Thereby, the abrasion resistance of the guide surface of a collar part can be improved.

  The guide surface of the flange portion of the nozzle member may be subjected to hard chrome plating. In this case, the surface hardness of the guide surface of the collar portion can be increased, and the wear resistance of the guide surface of the collar portion can be improved.

The guide surface of the flange portion of the nozzle member may be an uneven surface. In this case, lubricating oil is held on the uneven surface, and the lubricity of the guide surface can be improved.
The uneven surface may be a surface processed using a femtosecond laser. An extremely short pulse laser beam called a femtosecond laser is irradiated on the guide surface of the collar. Then, a finely processed surface having a depth of usually 0.1 μm or more and 1 μm or less is formed with a period according to the wavelength by the interference action of the laser light. Lubricating oil is reliably held on this finely processed surface.

  In the case where heat treatment is performed on at least a portion of the flange portion of the nozzle member that serves as a guide surface, the guide surface of the flange portion of the nozzle member is subjected to DLC coating treatment. Also good. In this case, the low friction property of the guide surface of the collar part can be improved.

  A groove extending in the bearing axial direction or in a direction inclined with respect to the bearing axial direction may be provided on the inner diameter surface or the outer diameter surface of the flange as the cage guide surface. In this case, pressure, that is, dynamic pressure, is generated in the lubricating oil existing in the cage guide clearance and the groove by the relative sliding movement between the circumferential surface of the cage and the inner diameter surface or outer diameter surface of the flange portion. Since the lubricating oil is smoothly guided along the groove by this dynamic pressure action, the lubricity over the entire circumference of the cage guide surface is further improved. In particular, when the groove extends in a direction inclined with respect to the bearing shaft direction, the dynamic pressure can be generated more effectively by the above-described relative sliding motion.

Either one or both of the inner ring and the cylindrical roller may be made of ceramics.
The ceramic is represented by a composition formula of _{Si 6-Z AL Z O Z} N 8-Z, it may be a sintered body mainly composed of β-sialon satisfying 0.1 ≦ Z ≦ 3.5.
The case where the ceramic is a sintered body mainly composed of silicon nitride will be described as an example.
A comparison is made between a rolling bearing (steel inner ring type) in which both the inner ring and the outer ring are made of steel, and a rolling bearing (ceramic inner ring type) in which the inner ring is made of silicon nitride and the outer ring is made of steel. Since the linear expansion coefficient of steel is about 11 × 10 ⁻⁶ and that of silicon nitride is about 3.2 × 10 ^−6, it is assumed that the temperature of the inner ring is higher than that of the outer ring during operation. The inner ring type has a larger radial clearance (usually a negative clearance on machine tools) between the rolling elements and the inner and outer rings during operation than the steel inner ring type (the absolute value as a negative value is small). Therefore, the ceramic inner ring type can alleviate the excessive preload phenomenon and is excellent in high-speed rotation performance. The excessive preload phenomenon is a phenomenon in which the rolling elements are excessively compressed in the radial direction, and is a major factor that hinders the high-speed rotation performance of the rolling bearing.

Since the density of steel is 7.8 × 10 ³ kg / m ³ and the density of silicon nitride is 3.2 × 10 ³ kg / m ³ , considering the difference in density between the two, excessive preload due to centrifugal expansion On the other hand, the ceramic inner ring type is particularly advantageous during high-speed rotation as compared with the steel inner ring type.
Furthermore, since the Young's modulus of steel is about 210 GPa and the Young's modulus of silicon nitride is about 314 GPa, the inner ring type made of ceramic is more advantageous in terms of bearing rigidity than the inner ring type made of steel.

  The above explanation is about the case where the ceramic is a sintered body mainly composed of silicon nitride, but the same can be said about the case where the ceramic is a sintered body mainly composed of β sialon. In addition, a sintered body mainly composed of β sialon has an advantage that it can be manufactured at a lower cost than a sintered body mainly composed of silicon nitride.

When the inner ring is made of ceramics, the rolling elements are preferably made of ceramics in order to further increase the speed. When the rolling element is also composed of ceramics, the rolling element may be composed of ceramics of a different type from the inner ring.
If the rolling elements are also made of ceramics, as in the case where the inner ring is made of ceramics, it is advantageous at the time of high-speed rotation against excessive preload due to thermal expansion or centrifugal expansion, so that the speed of the bearing can be further increased. In that case, the inner ring and the rolling element can be made of different types of ceramics in consideration of manufacturing convenience and the like.

  The method of discharging the lubricant from the nozzle hole of the nozzle member may be an air oil lubrication method or an oil mist lubrication method. In the case of the air-oil lubrication method, a minute amount of lubrication is easy to perform, and a cooling effect by air can be obtained.

  A cylindrical roller bearing device may be used for supporting the spindle of the machine tool. In this case, it is possible to reduce the manufacturing cost of the component parts and to increase the speed of the spindle.

  The cylindrical roller bearing device according to the present invention is provided adjacent to both sides of the outer ring in the axial direction, and a cylindrical roller bearing in which a plurality of cylindrical rollers held by an annular cage are interposed between the raceway surfaces of the inner and outer rings. A cylindrical roller bearing device including a nozzle member for discharging a lubricant into a bearing space between the inner and outer rings, wherein the inner ring and the outer ring have no collar portion, and the nozzle member is inserted into the bearing space and is a nozzle for the lubricant An annular flange having a hole is provided, and the tip surface of this flange is arranged on the inner ring side or the outer ring side, and is a roller guide surface that guides the end surface of the cylindrical roller. Can be reduced, and the speed of the bearing can be increased.

It is sectional drawing of the cylindrical roller bearing apparatus which concerns on one Embodiment of this invention. (A) is an expanded sectional view of the principal part of the cylindrical roller bearing device, and (B) is an enlarged sectional view showing the guide surface of the flange portion of the nozzle member in the cylindrical roller bearing device. (A) is sectional drawing of the cylindrical roller bearing apparatus which concerns on other embodiment of this invention, (B) is sectional drawing which expands and shows the guide surface etc. of the collar part of the nozzle member in the cylindrical roller bearing apparatus. It is an expanded sectional view of the principal part of the cylindrical roller bearing device which concerns on other embodiment of this invention. It is an expanded sectional view of the principal part of the cylindrical roller bearing device which concerns on other embodiment of this invention. It is an expanded sectional view of the principal part of the cylindrical roller bearing device which concerns on other embodiment of this invention. It is an expanded sectional view of the principal part of the cylindrical roller bearing device which concerns on other embodiment of this invention. It is an enlarged plan view of the principal part of the cylindrical roller bearing device which concerns on other embodiment of this invention. It is sectional drawing of the high-speed spindle apparatus provided with the cylindrical roller bearing apparatus of embodiment of this invention.

An embodiment of the present invention will be described with reference to FIGS.
The cylindrical roller bearing device according to this embodiment is used as a main shaft bearing of a machine tool. The cylindrical roller bearing device includes a cylindrical roller bearing 1 and a nozzle member 3 provided adjacent to the outer ring 2 of the cylindrical roller bearing 1. The rolling bearing 1 includes an inner ring 4, an outer ring 2, a plurality of cylindrical rollers 5 interposed between the raceway surfaces 4 a and 2 a of the inner and outer rings 4 and 2, and these cylindrical rollers 5 held at regular intervals in the circumferential direction. And an annular cage 6. The cage 6 is made of, for example, a resin material such as laminated phenol resin, polyamide, PEEK, steel, copper alloy, magnesium alloy, or the like.

  The inner ring 4 is fitted to the outer diameter surface of the main shaft (not shown). The inner ring 4 has no collar portion, and the outer ring surface of the inner ring 4 on both sides in the axial direction of the raceway surface 4a is provided with a slope portion 4b that increases in diameter from the inner ring end surface side toward the raceway surface 4a side. Yes. Accordingly, the outer ring surface of the inner ring is connected to the one inclined surface portion 4b through the raceway surface 4a.

  The outer ring 2 is fixed in a bearing box (not shown). The outer ring 2 has no collar portion. Outer ring positioning spacers 7 are respectively disposed on both sides in the axial direction of the outer ring 2 adjacent to the outer ring end face, and a nozzle member 3 described later is integrally provided on the inner diameter side portion of each outer ring positioning spacer 7. In the outer ring 2, on the inner diameter surfaces on both sides in the axial direction of the raceway surface 2a, slope portions 2b having a smaller diameter from the outer ring end surface side toward the raceway surface 2a side are provided. Therefore, the inner ring surface of the outer ring is connected to one inclined surface portion 2b via the raceway surface 2a. In this example, the inner and outer rings 2 and 4 are made of bearing steel, but are not limited to bearing steel.

  The outer ring positioning spacer 7 including the nozzle member 3 is made of bearing steel or the like, for example, and is fixed in the bearing box. The outer ring positioning spacer 7 positions the outer ring 2 in the axial direction. The nozzle member 3 discharges a lubricant into the bearing space between the inner and outer rings 1 and 2, and as this lubricant, air oil in which lubricating oil is mixed into the carrier air is used. The nozzle member 3 includes an annular flange 8 inserted into the bearing space and having an air oil nozzle hole 8a, and a nozzle member main body 9 provided integrally with the flange 8. The outer diameter side portion of the nozzle member body 9 is integrally formed with the inner diameter side portion of the outer ring positioning spacer 7.

  An air oil supply passage 10 and a discharge passage 11 are formed in the outer ring positioning spacer 7. The supply passage 10 is an oil passage for supplying air oil to the nozzle hole 8 a of the flange portion 8. The supply path 10 communicates with the nozzle hole 8 a via the supply path 12 in the nozzle member main body 9. That is, the supply passages 10 and 12 are opened to a depth determined in the radial direction from the outer diameter surface of the outer ring positioning spacer 7 and communicate with the nozzle hole 8a. The nozzle holes 8 a are provided at regular intervals at a plurality of locations in the circumferential direction of the annular flange 8. Accordingly, the supply paths 10 and 12 communicating with the nozzle hole 8a are also arranged in the same phase as the nozzle hole position at a plurality of locations in the circumferential direction. Each nozzle hole 8a is inclined toward the inner diameter side toward the discharge-side tip. Air oil is discharged from the discharge-side tip of the nozzle hole 8a toward the vicinity of the inner ring end surface of the slope 4b of the inner ring 4.

  The discharge passage 11 is an oil passage that guides air oil used for bearing lubrication to the oil discharge passage in the bearing box. The discharge path 11 includes an annular groove 11a, an exhaust groove 11b, an exhaust hole 11c, and an annular step portion 11d. An annular groove 11a that faces the bearing space is formed on the spacer end face of the outer ring positioning spacer 7 that contacts the end face of the outer ring. The outer peripheral groove portion 11aa of the annular groove 11a is formed so as to have a larger diameter than the maximum diameter position on the slope portion 2b of the outer ring 2. The bottom surface of the annular groove 11 a is defined to have a dimension that does not interfere with the supply paths 10 and 12.

  The exhaust groove 11b is formed by notching a predetermined circumferential position on the end surface of the outer ring and the outer ring positioning spacer 7 in the radial direction, and communicates with the annular groove 11a. Further, the exhaust groove 11b communicates with an oil drain passage in the bearing box, and discharges a part of the air oil used for lubrication from the oil drain passage. In this example, the exhaust groove 11b is provided only at one place in the circumferential direction of the outer ring positioning spacer 7, but it may be provided at a plurality of places.

  In the outer ring positioning spacer 7, an annular step portion 11 d is formed on the spacer end surface opposite to the spacer end surface where the annular groove 11 a is formed. The annular step portion 11d is formed by cutting out the radially inner peripheral portion of the spacer end surface in an annular shape. The outer circumferential groove portion 11da of the annular step portion 11d is disposed closer to the inner diameter side than the outer circumferential groove portion 11aa of the annular groove 11a. The exhaust hole 11c passes through the annular stepped portion 11d and the annular groove 11a in the outer ring positioning spacer 7. A plurality of the exhaust holes 11c are arranged at regular intervals in the circumferential direction. However, the plurality of exhaust holes 11 c are formed in positions in the circumferential direction different from the supply paths 10 and 12 of the outer ring positioning spacer 7 and do not interfere with the supply paths 10 and 12. The air oil used for lubrication is sequentially guided to the oil drainage passage of the bearing box through the annular groove 11a, the exhaust hole 11c, and the annular step portion 11d.

  As shown in FIG. 2 (B), the inner diameter surface 8b of the flange portion 8 in the nozzle member 3 forms a minute gap δ1 with the inclined surface portion 4b along the corresponding inclined surface portion 4b of the inner ring 4. The front end surface of the flange portion 8 is a roller guide surface 8 c that guides the end surface of the cylindrical roller 5. The outer diameter surface of the flange portion 8 is a cage guide surface 8d, and the cage inner diameter surface 6a is guided by the cage guide surface 8d of the flange portion 8. Further, at the proximal end portion of the outer diameter surface of the flange portion 8, a polishing shading 8 e for polishing the cage guide surface 8 d of the flange portion 8 is formed, for example.

The effect of this cylindrical roller bearing device will be described.
Lubricating oil discharged from the nozzle member 3 is attached to the inclined surface portion 4b of the inner ring 4 and supplied to the bearing space inside the bearing using the flow of attachment generated by the centrifugal force and the surface tension of the oil accompanying the rotation of the inner ring 4. To do. Considering the oil flow during the operation of the bearing, the lubricating oil discharged from the nozzle member 3 adheres to the inclined surface portion 4b of the inner ring 4 and moves inward of the bearing by the centrifugal force generated by the rotation of the inner ring. The lubricating oil scatters in the radial direction at the edge portion 4c that changes from the inclined surface portion 4b to the raceway surface 4a.

  The scattered oil flows into the bearing by the air flow and contributes to the lubrication of the raceway surfaces 4a and 2a and the cage pocket Pt. Further, a part of the oil scattered from the edge portion 4c of the inner ring 4 is received by the inner diameter surface 8b of the flange portion 8, and the roller guide surface 8c of the flange portion 8 which becomes the roller guide surface by the air flow in the minute gap δ1, Furthermore, it moves to the cage guide surface 8d that serves as a guide for the cage 6. Thereby, the roller guide surface 8c and the cage guide surface 8d are lubricated.

  The oil used for lubrication is discharged to the outside of the bearing from the exhaust hole 11c and the exhaust groove 11b of the outer ring positioning spacer 7 by the air flow inside the bearing accompanying rotation. In this configuration, the front end surface of the flange portion 8 of the nozzle member 3 is a roller guide surface 8c that guides the end surface of the cylindrical roller 5, so that a collar portion that becomes an obstacle to oil discharge is provided on the raceway portion of the outer ring 2. Need not be provided. For this reason, oil can be easily discharged from the bearing. As a result, oil stagnation in the raceway portion of the outer ring 2 can be suppressed, and problems such as heat generation due to oil stagnation can be solved. As a result, it is possible to increase the speed of the bearing, and it is possible to maintain the machining accuracy with high accuracy particularly in the machine tool spindle application. Further, since the front end surface of the flange portion 8 is a roller guide surface 8c, it is not necessary to provide a collar portion for guiding the cylindrical roller 5 on the inner and outer rings 4 and 2, so that the shapes of the inner and outer rings 4 and 2 are of the prior art. It can be simplified further. Therefore, it is possible to reduce the number of man-hours such as machining after molding the inner and outer rings, and accordingly, the manufacturing cost can be reduced.

  Since the outer diameter surface of the flange portion 8 of the nozzle member 3 is a cage guide surface 8d that guides the inner peripheral surface of the cage 6, the whirling of the cage 6 becomes large or the same due to interference with the cylindrical roller 5. The problem that the cage pocket Pt holding the cylindrical roller 5 is damaged can be solved. In the guide method of the cage 6 in this case, the peripheral speed on the guide surface is small and the sliding speed is low compared to the outer ring guide method. For this reason, the bearing power loss is small, the bearing temperature can be suppressed, and this is advantageous in terms of preload management.

A cylindrical roller bearing device according to another embodiment of the present invention will be described with reference to FIG.
The flange 8 of the nozzle member 3 in this cylindrical roller bearing device has first and second flanges 8A and 8B. The first flange portion 8A is disposed between the inner diameter surface of the outer ring 2 and the cage outer diameter surface 6b, and the tip surface of the first flange portion 8A is a roller guide for guiding the end surface of the cylindrical roller 5. Let it be surface 8Aa. At the same time, the inner diameter surface of the first flange portion 8A is referred to as a cage guide surface 8Ab that guides the outer peripheral surface of the cage. A small clearance δ1 is formed between the inner diameter surface 8Ba of the second flange portion 8B and the inclined surface portion 4b of the inner ring 4. Other configurations are the same as those in FIGS. 1 and 2. According to this configuration, in particular, since the inner diameter surface of the first flange portion 8A is the cage guide surface 8Ab, the swinging of the cage 6 can be further reduced as compared with the configuration of FIGS. Therefore, it is possible to more reliably prevent the pocket Pt of the cage 6 from being damaged due to interference with the cylindrical roller 5.
On the other hand, in this type, the friction torque here becomes large as the guide surface becomes the outer diameter side. However, the frictional torque due to contact between the flange surfaces and the end surfaces is advantageous for the outer ring side collar structure where the contact position from the outer ring raceway surface is close. That is, the two-part structure has advantages and disadvantages, and the arrangement of the collars is determined in consideration of the actual lubrication method and lubrication conditions. The inner ring side collar structure is preferable when the lubricating oil to the collar part is abundant, and the outer ring side collar structure is preferable when the lubrication of the collar part is lean. Further, since the front end surface of the first flange portion 8A is the roller guide surface 8Aa, it is not necessary to provide a flange portion for guiding the cylindrical roller 5 on the inner and outer rings 4 and 2, so the shape of the inner and outer rings 4 and 2 is the conventional technology. It can be made simpler than that. Therefore, it is possible to reduce the number of man-hours such as machining after molding the inner and outer rings, and accordingly, the manufacturing cost can be reduced.

  As shown in FIG. 4, a clearance angle α with respect to the end surface of the cylindrical roller 5 may be provided on the tip surface of the flange portion 8 that is the roller guide surface 8 c. For example, in response to irregular movements such as skew and dance of the cylindrical roller 5 that occur during the bearing operation, an inclination angle, that is, a clearance angle, that is separated from the end surface of the cylindrical roller 5 toward the outer diameter side on the distal end surface of the flange portion 8. α is provided. According to this configuration, it is possible to avoid abnormal contact between the end surface of the cylindrical roller 5 and the front end surface of the flange portion 8 due to the occurrence of irregular motion during bearing operation.

  As shown by cross-hatching in FIG. 5, in the flange portion 8 of the nozzle member 3, a portion 13 including a tip surface serving as a roller guide surface 8 c and a portion 14 including an outer diameter surface serving as a cage guide surface 8 d, You may heat-process. The portions 13 and 14 to be heat-treated can be heat-treated by, for example, induction hardening. The entire outer ring positioning spacer 7 including the nozzle member 3 may be heat-treated. Since a plurality of outer ring positioning spacers 7 can be put into, for example, a heat treatment furnace and subjected to heat treatment, man-hours can be reduced as compared with the case of FIG.

Since the guide surfaces 8c and 8d of the flange portion 8 of the nozzle member 3 slide while contacting during operation of the bearing, it is necessary to consider wear resistance and the like. When heat treatment is performed on at least the portions 13 and 14 that become the guide surfaces 8c and 8d of the flange portion 8, the surface hardness of the guide surfaces 8c and 8d of the flange portion 8 can be made higher than that before the heat treatment. Thereby, the abrasion resistance of the guide surfaces 8c and 8d of the collar portion 8 can be improved.
As described above, at least the portions 13 and 14 which become the guide surfaces 8c and 8d of the flange portion 8 are heat-treated, and then the guide surfaces 8c and 8d are coated with diamond like carbon (abbreviated as DLC). Processing may be performed. In this case, the low friction property of the guide surfaces 8c and 8d of the collar portion 8 can be improved.

  As shown in FIG. 6, the roller guide surface 8 c and the cage guide surface 8 d in the flange portion 8 of the nozzle member 3 may be subjected to a surface treatment Ha such as hard chrome plating. In this case, the surface hardness of the guide surfaces 8c and 8d of the flange portion 8 can be increased, and the wear resistance of the guide surfaces 8c and 8d of the flange portion 8 can be improved.

As shown in FIG. 7, the roller guide surface 8c and the cage guide surface 8d of the flange portion 8 may be a concavo-convex surface Hb. As a method for processing the uneven surface Hb, for example, random unevenness is formed on the roller guide surface 8c and the cage guide surface 8d of the flange portion 8 using a tip by a centrifugal fluid barrel polishing method. Thereafter, the flange 8 is washed, and a surface finishing process is performed on the uneven portions by the barrel polishing method to remove or round the surface minute protrusions. As a result, an infinite number of minute recesses are formed in the roller guide surface 8c and the cage guide surface 8d of the flange portion 8, and the surface roughness of the roller guide surface 8c and the cage guide surface 8d of the flange portion becomes a desired value. Like that. Therefore, a rough surface is formed on the roller guide surface 8c and the cage guide surface 8d. Such processing is referred to as high lubrication processing (abbreviated as HL processing).
Lubricating oil is held on the minute uneven surface Hb processed as described above, and the lubricity of the roller guide surface 8c and the cage guide surface 8d of the flange portion 8 can be improved.

  The uneven surface Hb may be a surface processed using a femtosecond laser. The guide surfaces 8c and 8d of the collar portion 8 are irradiated with laser light of an extremely short pulse called a femtosecond laser. Then, a finely processed surface having a depth of usually 0.1 μm or more and 1 μm or less is formed with a period according to the wavelength by the interference action of the laser light. Lubricating oil is reliably held on this finely processed surface. Therefore, the lubricity of the roller guide surface 8c and the cage guide surface 8d of the flange portion 8 can be improved.

  FIG. 8 is a plan view of an essential part of a cage guide surface of a flange portion of a nozzle member in a cylindrical roller bearing device according to still another embodiment. In this example, the bearing shaft direction (FIG. 8 (A)) indicated by the arrow L1 or the direction inclined with respect to the bearing shaft direction on the inner diameter surface or outer diameter surface of the flange portion 8 as the cage guide surface 8d. A groove Ma extending in (FIG. 8B) may be provided. In this case, pressure, that is, dynamic pressure, is generated in the lubricating oil existing in the cage guide clearance and the groove Ma by the relative sliding motion between the peripheral surface of the cage 6 and the inner diameter surface or outer diameter surface of the flange portion 8. Since the lubricating oil is smoothly guided along the groove Ma by this dynamic pressure action, the lubricity over the entire circumference of the cage guide surface 8d is further improved. In particular, as shown in FIG. 8B, when the groove Ma extends in a direction inclined with respect to the bearing axis direction, it is possible to generate dynamic pressure more effectively by the above-described relative sliding motion.

Either one or both of the inner ring 4 and the cylindrical roller 5 may be made of ceramics.
When the ceramic is a sintered body containing silicon nitride as a main component, the rolling bearing including the inner ring 4 made of ceramics is the inner ring made of steel because of the difference between the linear expansion coefficient of silicon nitride and the linear expansion coefficient of steel. The radial clearance between the rolling element and the inner and outer rings during operation is larger than that of the rolling bearing including 4. Therefore, the rolling bearing including the inner ring 4 made of ceramics can alleviate the excessive preload phenomenon and is excellent in high-speed rotation performance. The excessive preload phenomenon is a phenomenon in which the rolling elements are excessively compressed in the radial direction, and is a major factor that hinders the high-speed rotation performance of the rolling bearing.

Since the density of steel is 7.8 × 10 ³ kg / m ³ and the density of silicon nitride is 3.2 × 10 ³ kg / m ³ , considering the difference in density between the two, excessive preload due to centrifugal expansion On the other hand, the rolling bearing of the ceramic inner ring is particularly advantageous at the time of high-speed rotation as compared with the rolling bearing of the steel inner ring.
Further, since the Young's modulus of steel is about 210 GPa and the Young's modulus of silicon nitride is about 314 GPa, the rolling bearing of the ceramic inner ring is advantageous in terms of the bearing rigidity as compared with the rolling bearing of the steel inner ring.
The ceramic is represented by a composition formula of _{Si 6-Z AL Z O Z} N 8-Z, it may be a sintered body mainly composed of β-sialon satisfying 0.1 ≦ Z ≦ 3.5. When the ceramic is a sintered body containing β sialon as a main component, it can be manufactured at a lower cost than a sintered body containing silicon nitride as a main component.

In each of the above embodiments, the air oil lubrication method is employed, but an oil mist lubrication method may be employed.
In each embodiment, the outer ring 2 may be provided with a collar portion.
The nozzle member 3 may be provided separately from the outer ring positioning spacer 7, and the separate nozzle member 3 may be fixedly provided on an inner peripheral side portion of the outer ring positioning spacer 7. In this case, only the separate nozzle member 3 can be subjected to the above-described heat treatment, processing of the uneven surface Hb, and the like. Therefore, it becomes easy to maintain the dimensional accuracy of the outer ring positioning spacer 7 with high accuracy.
Instead of the configuration of FIG. 7 or together with the configuration of FIG. 7, the above-described uneven surface Hb may be processed on the cage inner diameter surface (or the cage outer diameter surface) that is the guide surface of the cage 6. In this case, the lubricating oil is held on the concavo-convex surface Hb of the cage 6, and the lubricity of the cage guide surface 8d of the flange portion 8 can be improved.

  FIG. 9 shows an example of a high-speed spindle device including the cylindrical roller bearing device according to any one of the above embodiments. The spindle device SM is applied to a machine tool, and a tool or workpiece chuck is attached to the front side (machining side) end of the spindle 15. The main shaft 15 is supported on the front side in the axial direction by a set of two-row angular ball bearing type rolling bearing devices, and supported on the rear side in the axial direction by the cylindrical roller bearing device of any of the embodiments. The inner ring 4 of each rolling bearing is fitted to the outer diameter surface of the main shaft 15, and the outer ring 2 is fitted to the inner diameter surface of the bearing housing Hs.

  For the rolling bearing on the front side of the main shaft, the inner ring 4 is fixed in the bearing box Hs by the stepped surface 15a of the main shaft 15 and the outer ring 2 is fixed in the bearing housing Hs by the pressing lid 16A through the outer ring positioning spacer 17a. As for the roller bearing 1, the inner ring 4 is fixed in the bearing box Hs by the inner ring positioning spacer 17b and the outer ring 3 by the pressing lid 16B through the nozzle member 3. The bearing housing Hs has a double structure of an inner circumferential bearing housing HsA and an outer circumferential bearing housing HsB, and a cooling groove 18 is formed between the inner and outer bearing housings HsA and HsB. A bearing fixing nut 19 that is pressed against the inner ring positioning spacer 17 to fix the cylindrical roller bearing 1 is screwed to the rear end portion of the main shaft 15.

The holding lids 16A and 16B are provided with air oil introduction holes 21 for introducing air oil from the air oil supply devices 20A and 20B, which are supply sources when the bearings are air-oil lubricated, respectively. It communicates with an air oil supply path 22 provided in HsA. In addition, the holding lids 16A and 16B are provided with oil drain holes 23, and these oil drain holes 23 communicate with an oil drain passage 24 provided in the inner peripheral bearing box HsA.
In the spindle device SM configured as described above, since the cylindrical roller bearing device is incorporated, the manufacturing cost of the component parts can be reduced and the speed of the main shaft 15 can be increased.

DESCRIPTION OF SYMBOLS 1 ... Cylindrical roller bearing 2 ... Outer ring 2a ... Raceway surface 3 ... Nozzle member 4 ... Inner ring 4a ... Raceway surface 4b ... Slope part 5 ... Cylindrical roller 6 ... Cage 7 ... Outer ring positioning spacer 8 ... Eave part 8a ... Nozzle hole 8c ... Roller guide surface 8d ... Cage guide surface

Claims (16)

A cylindrical roller bearing in which a plurality of cylindrical rollers held by an annular cage are interposed between the raceway surfaces of the inner and outer rings, and adjacent to both sides in the axial direction of the outer ring, the bearing space between the inner and outer rings is lubricated. In a cylindrical roller bearing device provided with a nozzle member for discharging the agent,
The inner ring and outer ring have no collar part,
The nozzle member is provided with an annular flange that is inserted into the bearing space and has a nozzle hole for the lubricant, and the distal end surface of the flange is disposed on the inner ring side or the outer ring side to guide the end surface of the cylindrical roller. A cylindrical roller bearing device characterized by having a roller guide surface.   2. The cylindrical roller bearing device according to claim 1, wherein outer ring positioning spacers are respectively disposed on both axial sides of the outer ring, and the nozzle member is integrally provided on an inner peripheral side portion of each outer ring positioning spacer.   In Claim 1 or Claim 2, the slope part where the raceway side becomes large diameter is provided in the outer diameter surface of the inner ring, and the nozzle hole provided in the collar part of the nozzle member is provided in the slope part of the inner ring. Cylindrical roller bearing device that discharges lubricant toward   The cylindrical roller bearing device according to any one of claims 1 to 3, wherein an inner diameter surface or an outer diameter surface of the flange portion is a cage guide surface that guides a circumferential surface of the cage.   5. The cylindrical roller bearing device according to claim 1, wherein a clearance angle with respect to an end surface of the cylindrical roller is provided on a front end surface of the flange portion so that an outer diameter side is separated from an end surface of the cylindrical roller. .   6. The cylindrical roller bearing device according to claim 1, wherein heat treatment is performed on at least a portion of the flange portion of the nozzle member that serves as a guide surface. 7.   The cylindrical roller bearing device according to any one of claims 1 to 5, wherein a hard chrome plating is applied to a guide surface of the flange portion of the nozzle member.   The cylindrical roller bearing device according to any one of claims 1 to 7, wherein the guide surface of the flange portion of the nozzle member is an uneven surface.   The cylindrical roller bearing device according to claim 8, wherein the uneven surface is a surface processed using a femtosecond laser.   The cylindrical roller bearing device according to claim 6, wherein a DLC coating is applied to a guide surface of the flange portion of the nozzle member.   5. The cylindrical roller bearing device according to claim 4, wherein a groove extending in a bearing axis direction or a direction inclined with respect to the bearing axis direction is provided on an inner diameter surface or an outer diameter surface of the flange portion serving as the cage guide surface.   The cylindrical roller bearing device according to any one of claims 1 to 11, wherein one or both of the inner ring and the cylindrical roller are made of ceramics.   The cylindrical roller bearing device according to claim 12, wherein the ceramic is a sintered body containing silicon nitride as a main component. 13. The ceramic according to claim 12, wherein the ceramic is a sintered body mainly composed of β sialon represented by a composition formula of Si _6-Z AL _Z O _Z N _8-Z and satisfying 0.1 ≦ Z ≦ 3.5. Cylindrical roller bearing device.   The cylindrical roller bearing device according to any one of claims 1 to 14, wherein a method of discharging a lubricant from a nozzle hole of the nozzle member is an air oil lubrication method or an oil mist lubrication method.   The cylindrical roller bearing device according to any one of claims 1 to 15, wherein the cylindrical roller bearing device is used to support a main shaft of a machine tool.

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