JP2011169362A - Rolling bearing lubricating structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rolling bearing lubricating structure which is manufactured at low cost while compatibly realizing high speed of a bearing and solving an environmental problem. <P>SOLUTION: An inclined surface part 2b is provided on a side of a rolling surface 2a on an outside diameter surface of an inner ring 2 of a rolling bearing 1, and a grease tank 10 having a grease sump 11 therein is arranged adjacent to an outer ring 3 of the rolling bearing 1. A base oil moving medium 15 for moving base oil in grease by the capillary phenomenon is provided within the grease sump 11 of the grease tank 10, and one end thereof is brought into contact with the inclined surface part 2b. Thus, the base oil in the grease sealed in the grease sump 11 is deposited on the inclined surface part 2b along the base oil moving medium 15, and the base oil deposited on the inclined surface part 2b is fed into a bearing by using the surface surfactant of the base oil and the flow of the base oil along the inclined surface part 2b generated by the rotation of the inner ring 2. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a lubricating structure of a rolling bearing used for supporting a high-speed spindle such as a machine tool spindle.

  Recent machine tools have a tendency to increase the speed in order to increase the processing efficiency, and the speed of the bearing used for the main shaft is also required to meet the demand. In addition, environmental issues such as energy saving and resource saving have been highlighted. A lubrication method is an important technical issue for bearings against this increase in speed and environmental problems. As a general lubrication method for a main shaft bearing, there are grease lubrication, air-oil lubrication in which oil is mixed with compressed air and injected into the bearing from a nozzle, and jet lubrication in which oil is directly injected into the bearing using a nozzle. Each of these lubrication methods has advantages and disadvantages as described below.

  Grease lubrication is easy to handle, but is not suitable for high-speed bearings. Air-oil lubrication can be applied to bearings that rotate at high speed, but there are problems in terms of energy saving and environment, such as the need for a large amount of compressed air, the generation of oil mist, and the generation of noise. Jet lubrication can rotate the bearing at the highest speed among the three lubrication methods, but it requires additional equipment such as an oil supply device, and a large amount of oil causes a large power loss due to operation. For the reason, there is a problem from the viewpoint of energy saving and resource saving as well as air oil lubrication.

  Since the conventional lubrication methods have respective problems as described above, recently, a new lubrication method for the purpose of achieving both high speed and environmental problems has been proposed (Patent Document 1). That is, a grease tank filled with grease is provided adjacent to the bearing, and the base oil in the grease in the grease tank is separated and discharged into the bearing using a heat cycle generated in the bearing. .

JP 2009-103232 A

  In the proposed lubricating method, when the bearing is an angular ball bearing, the grease tank is arranged on the front side of the bearing. Usually, a pair of angular ball bearings is often used in combination with the back surface for supporting the spindle of the machine tool. Therefore, when the bearing and the grease tank are incorporated in the main shaft of the machine tool, the distance from the tool attached to the tip of the main shaft to the bearing is increased by the amount of the grease tank. The long distance is disadvantageous in terms of moment rigidity of the main shaft.

  Therefore, in order to be able to supply the lubricating oil from the bearing back side to the inside of the bearing, the lubricating oil in the oil tank provided outside is introduced into an oil supply member arranged near the bearing in the axial direction (for example, the bearing back side). We have come up with a lubrication method in which the tip of the capillarity generating member provided in the oil supply member is brought into contact with the outer diameter surface of the inner ring of the bearing, and the lubricant introduced into the oil supply member is supplied into the bearing through the capillarity generating member. . However, since this method requires an oil tank and piping for guiding the lubricating oil in the oil tank to the oil supply member, there is a problem that the cost is increased.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a rolling bearing lubrication structure that can be manufactured at low cost while achieving both high speed bearings and environmental problems.

  The lubrication structure of the rolling bearing according to the present invention is a grease in which a slope portion is provided on the side of the rolling surface of the outer diameter surface of the inner ring of the rolling bearing and a grease reservoir is formed in the inside adjacent to the outer ring of the rolling bearing. A tank is provided, and a base oil moving medium for moving the base oil in the grease by capillary action is provided in the grease reservoir of the grease tank, and one end of the base oil moving medium is brought into contact with the inclined surface portion, and the grease reservoir The base oil in the grease sealed in is attached to the slope portion through the base oil moving medium, and the base oil attached to the slope portion is caused by the surface tension of the base oil and the rotation of the inner ring. It is characterized in that it is supplied into the bearing using the base oil adhering flow along the part.

  In the lubricating structure of this configuration, grease is sealed in the rolling bearing and grease is sealed in the grease reservoir of the grease tank at the time of assembly. The bearing is lubricated with the initially charged grease and the grease in the grease reservoir. The base oil in the grease in the grease reservoir adheres to the slope of the inner ring by the base oil extraction and movement caused by the capillary phenomenon of the base oil moving medium. The base oil adhering to the slope portion moves toward the bearing inside along the slope portion due to the surface tension of the base oil and the centrifugal force accompanying the rotation of the inner ring, and is used as lubricating oil. As described above, since the grease is contained in the grease reservoir in addition to the initial sealed grease inside the bearing, the lubrication reliability is high and the life of the bearing can be extended.

  In this lubricating structure, when the rolling bearing is a bearing having a contact angle such as an angular ball bearing, the grease tank may be arranged on either the front side or the back side of the rolling bearing. Usually, a pair of angular ball bearings is often used in combination with the back surface for supporting the spindle of the machine tool. In that case, by arranging the grease tank on the back side of the rolling bearing, it is possible to design the distance from the rolling bearing to the tip of the main shaft to be the shortest. In a machine tool, a tool is attached to the tip of a spindle. If the distance from the rolling bearing to the tip of the main shaft is short, the moment rigidity against the external force load acting on the tool is large, which is structurally advantageous.

  Since the base oil of grease sealed in the grease reservoir of the grease tank is used as the lubricating oil, an oil tank and piping are not required outside. There is no need to process the oil introduction hole in the bearing housing. Therefore, the structure is simple and can be manufactured at low cost. In addition, since a large amount of oil is not used and driving power for lubrication is not required, it is preferable from the viewpoint of energy saving and resource saving. Furthermore, because of grease lubrication, no maintenance is required.

In the present invention, the grease tank may have a medium insertion clearance that allows the grease reservoir to communicate with the outside, and the base oil moving medium may be inserted into the medium insertion clearance. In that case, an outer diameter side portion of the medium insertion clearance in the outer shell of the grease tank is formed as a cylindrical portion that covers the slope portion of the inner ring through the clearance portion, and the medium insertion clearance in the cylindrical portion is Further, it is preferable that the inner diameter surface of the portion protruding toward the axial center side of the bearing is shaped to guide the portion of the base oil moving medium outside the grease reservoir so that the tip is in contact with the slope portion.
By inserting the base oil moving medium through the medium insertion clearance provided in the grease tank, the base oil in the grease is transferred to the base oil moving medium while preventing leakage of grease or base oil from the grease reservoir. It can be led out. A cylindrical part is formed in the grease tank, and the inner diameter surface of the grease tank is shaped so as to guide the part outside the grease reservoir of the base oil moving medium so that the tip comes into contact with the inclined surface part. It can be made to contact a slope part reliably.

In the present invention, it is preferable that a circumferential groove having a V-shaped cross section is provided on the slope portion, and one end of the base oil moving medium is brought into contact with the slope of the circumferential groove on the rolling surface side.
If the circumferential groove is provided on the slope, the oil that adheres to the slope of the inner ring and the oil that is supplied from the grease in the grease reservoir through the base oil moving medium when the operation is stopped are used as the circumferential groove. It is temporarily held. The oil retained in the circumferential groove at the start can be used again as the lubricating oil, and lubrication can always be performed with abundant lubricating oil. By setting the circumferential groove to have a V-shaped cross section, the base oil discharged from one end of the base oil moving medium to the slope on the rolling surface side of the circumferential groove easily moves to the slope portion of the inner ring outer diameter surface. The slope of the slope of the circumferential groove is determined by the practical rotational speed of the inner ring. Specifically, the slope is increased as the speed increases.

In the present invention, a step portion having a small diameter on the side far from the rolling surface may be provided on the slope portion, and one end of the base oil moving medium may be brought into contact with the step surface of the step portion. In a broad sense, the step surface is a part of the slope.
In this case, the base oil extracted from the grease in the grease reservoir adheres to the step surface of the inner ring by the base oil moving medium. The base oil adhering to the step surface moves from the step surface to the slope portion, moves along the slope portion toward the inside of the bearing, and is used as lubricating oil. By providing the stepped portion on the slope portion in this manner, the oil can be temporarily held in the stepped portion when operation is stopped, and lubrication can always be performed with abundant lubricating oil.

In the present invention, angle alpha (°) of the inclined surface portion with respect to the bearing center line, a ball pitch circle diameter _d m (mm), if the rotational speed was n ^{(min -1),}
_{α ≧ {0.056 · (d m} n ^{value) 10-4}} -2
It is good to make this relationship hold.
Preferred values for the angle of the inclined surface portion of the inner ring outer diametric surface varies depending d _{m n} values of the bearing. As a result of the test, it was found that the angle α of the slope portion should be a value represented by the above formula. Incidentally, d m _n value is a numerical value indicating the high-speed level of conditions of use of the radial bearing, is expressed by the product of the allowable rotation speed n and the average value d _m of the bearing inner and outer diameters.

In the present invention, the base oil moving medium is made of a material that causes capillary action, and Japanese paper, cloth (including both woven and non-woven cloth), leather, and the like can be used.
Each material has a property of extracting and containing a base oil from grease and a property of moving the contained oil by capillary action. Therefore, the base oil is suitable as a material for the base oil moving medium that extracts the base oil from the grease in the grease reservoir and guides it to the slope portion of the inner ring outer diameter surface.

In this invention, it is preferable that the base oil moving medium is provided in the grease tank so that the circumferential length of the contact portion with the slope portion can be adjusted.
If the base oil moving medium can adjust the circumferential length of the contact portion with the slope portion, the amount of oil adhering to the inner ring slope portion can be adjusted by adjusting the circumferential length.

In the present invention, a portion of the base oil moving medium in the grease reservoir may be branched into a plurality of branch portions separated from each other in the circumferential direction.
If the portion in the grease reservoir of the base oil moving medium is branched as described above, each branch can be dispersed and arranged in a wide area of the grease reservoir, and the base oil can be efficiently distributed from the entire area of the grease reservoir. Can be extracted.

In the present invention, the grease tank may be made of steel or resin. In that case, it can be formed by machining. Molding by machining is easy.
When the grease tank is made of resin, it can be formed by injection molding. Injection molding is easier to mold, and a grease tank can be manufactured at low cost.

  The present invention can be applied to the case where the rolling bearing is an angular ball bearing or a cylindrical roller bearing.

  The lubrication structure for a rolling bearing according to the present invention can be suitably used for supporting a machine tool spindle that rotates at a high speed because the above-described effects can be obtained.

  The lubrication structure of the rolling bearing according to the present invention is a grease in which a slope portion is provided on the side of the rolling surface of the outer diameter surface of the inner ring of the rolling bearing and a grease reservoir is formed in the inside adjacent to the outer ring of the rolling bearing. A tank is provided, and a base oil moving medium for moving the base oil in the grease by capillary action is provided in the grease reservoir of the grease tank, and one end of the base oil moving medium is brought into contact with the inclined surface portion, and the grease reservoir The base oil in the grease sealed in is attached to the slope portion through the base oil moving medium, and the base oil attached to the slope portion is caused by the surface tension of the base oil and the rotation of the inner ring. Since the base oil adhering flow along the part is used to supply the bearing into the bearing, it can be manufactured at low cost while achieving both high speed bearings and environmental problems.

It is sectional drawing of the lubricating structure of the rolling bearing concerning one Embodiment of this invention. It is the elements on larger scale of the lubrication structure of the rolling bearing. It is the figure which looked at an example of the base oil movement medium in the lubrication structure of the rolling bearing from the axial direction. It is the figure which looked at the example from which the same base oil movement medium differs from the axial direction. It is sectional drawing of the main axis | shaft apparatus to which the lubrication structure of the rolling bearing is applied. It is sectional drawing which shows a part of lubricating structure of the rolling bearing concerning different embodiment of this invention. It is a figure which expands the base oil movement medium in the same lubricating structure in the circumference direction, and shows a part It is sectional drawing which shows a part of lubricating structure of the rolling bearing concerning further different embodiment of this invention. It is sectional drawing which shows a part of lubricating structure of the rolling bearing concerning further different embodiment of this invention. It is sectional drawing of the lubrication structure of the rolling bearing concerning further different embodiment of this invention.

  An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of the entire lubricating structure of a rolling bearing, and FIG. 2 is a partially enlarged view thereof. The lubrication structure of this rolling bearing is applied to the rolling bearing 1 which is an angular ball bearing, and a grease tank 10 is disposed adjacent to the back side of the rolling bearing 1.

  The rolling bearing 1 includes an inner ring 2, an outer ring 3, and a plurality of rolling elements 4 interposed between the rolling surfaces 2 a and 3 a of the inner and outer rings 2 and 3. The rolling elements 4 are formed of balls, and each rolling element 4 is held in a pocket 5 a of a cage 5. The front side end of the bearing space between the inner and outer rings 2 and 3 is sealed with a seal 6. The grease tank 10 also serves as a seal on the bearing back side, and no seal is provided at the back side end of the bearing space. The inner ring 2, the outer ring 3, and the rolling element 4 are made of a steel material such as bearing steel, ceramics, or the like. The cage 5 is made of resin or the like.

The portion on the back side of the outer diameter surface of the inner ring 2 with respect to the transfer surface 2a is a slope portion 2b having a smaller diameter toward the outer side in the axial direction. The angle α (°) of the slope portion 2b with respect to the bearing center line O is determined by the practical rotational speed of the inner ring 2. Specifically, the angle α is increased as the speed increases. For example, if the maximum operating speed is 2 million d _{m n} value, the angle α to 9 ° or higher. In general,
the formula of _{α ≧ {0.056 · (d m} n ^{value) 10-4}} -2. This equation is obtained from the test results. However, the _{d m} ball pitch circle diameter (mm), n is the rotational speed ^{(min -1).}

  A circumferential groove 7 having a V-shaped cross section is provided in a part of the slope portion 2b. In the illustrated example, the side surface on the inner side in the axial direction of the circumferential groove 7 is a slope 7a, and the side surface on the outer side in the axial direction is a radial surface 7b. The slope 7a and the slope 2b are connected to a smooth curve. The axial position of the circumferential groove 7 is slightly outside the center of the slope portion 2b.

  The grease tank 10 is an annular component having a hollow grease reservoir 11 formed therein, and includes a grease tank main body 12 and a grease tank tip member 13. Specifically, the grease tank body 12 connects the inner peripheral wall portion 12a along the axial direction, the outer peripheral wall portion 12b parallel to the inner peripheral wall portion 12a, and the bearing back side of the inner peripheral wall portion 12a and the outer peripheral wall portion 12b. It consists of a back wall 12c. Further, the grease tank tip member 13 is provided in a state of being fitted between the inner peripheral wall portion 12a and the outer peripheral wall portion 12b so as to close the bearing front side opening of the grease tank main body 12.

  The inner peripheral portion of the grease tank tip member 13 is a cylindrical portion 13a extending to the bearing front side. The inner diameter surface of the proximal end portion of the cylindrical portion 13a and the bearing side of the inner peripheral wall portion 12a of the grease tank body 12 A medium insertion gap 14 is formed between the outer diameter surface of the end portion. The size of the medium insertion clearance 14 is such that a base oil moving medium 15 described later can be inserted. The cylindrical portion 13a of the grease tank tip member 13 protrudes toward the axial center side of the bearing from the medium insertion clearance 14, and covers the inclined surface 2b of the inner ring 2 via a clearance δ. A convex portion 13b that protrudes toward the inner peripheral side is formed at the tip of the cylindrical portion 13a. A side surface of the convex portion 13b facing the medium insertion clearance 14 is a tapered surface 13c having a larger diameter toward the medium insertion clearance 14 side. As a result, the inner diameter surface of the cylindrical portion 13a that protrudes further toward the axial center side of the bearing than the medium insertion clearance 14 serves as the outer diameter of the inner ring 2 at the tip of the base oil moving medium 15 that will be described later. It is made into the shape guided so that it may contact the slope 7a of the V-shaped circumferential groove 7 in a surface.

  Grease is sealed in the grease reservoir 11 of the grease tank 10. Further, a base oil moving medium 15 is inserted into the grease reservoir 11, and one end thereof passes through the medium insertion gap 14 and protrudes outside the grease reservoir 11. The base oil moving medium 15 extracts base oil from grease and moves the base oil by capillary action, and is made of, for example, Japanese paper, cloth, leather, felt, or the like. The cloth may be woven or non-woven. It is desirable that the end of the base oil moving medium 15 in the grease reservoir 11 extends to the vicinity of the back wall 12c of the grease tank body 12. The base oil moving medium 15 may be cylindrical and provided over the entire circumference as shown in FIG. 3, or a plurality of base oil moving media 15a having an arbitrary circumferential width as shown in FIG. May be distributed over the entire circumference. In the latter case, the circumferential length of the entire base oil moving medium 15 can be adjusted, and the amount of base oil extracted thereby can be adjusted.

  The grease tank 10 is made of steel or resin. In either case, it can be formed by machining. Molding by machining is easy. Moreover, when it is resin, it can shape | mold by injection molding. Since injection molding is easier than molding, the grease tank 10 can be manufactured at low cost.

  The grease tank 10 is assembled adjacent to the rolling bearing 1 such that the bearing-side surface of the grease tank tip member 13 contacts the end surface of the outer ring 3 on the bearing back side. The portion of the base oil moving medium 15 that protrudes from the grease reservoir 11 abuts on the tapered surface 13c of the cylindrical portion 13a and changes its direction to the inner diameter side, and its tip is in light contact with the inclined surface 7a of the circumferential groove 7. The slope portion 2b of the inner ring 2 and the convex portion 13b of the grease tank tip member 13 are opposed to each other via a gap δ. An O-ring 16 is provided between the bearing side end surface of the outer peripheral wall portion 12 b of the grease reservoir main body 12 and the end surface of the outer ring 3 on the bearing back side.

  In the assembled state of the grease tank 10, the outer ring spacer 17 is fitted to the outer periphery of the grease tank 10, and the step surface 17 a of the outer ring spacer 17 is engaged with the bearing rear side end of the outer peripheral wall portion 12 b of the grease reservoir main body 12. To do. Thereby, the axial position of the grease tank 10 is restrained. The inner ring 2 is positioned by an inner ring spacer 18. The outer ring spacer 17 and the inner ring spacer 18 are made of steel.

  FIG. 5 shows an example of a spindle device that employs the rolling bearing lubrication structure shown in FIGS. 1 and 2. This spindle device is for a machine tool. A tool or workpiece chuck (not shown) is attached to one end 20a of the spindle 20, and a drive source such as a motor is connected to a rotation transmission mechanism (the other end 20b). (Not shown). The main shaft 20 is rotatably supported by a pair of rolling bearings 1 separated in the axial direction. In the example of the figure, the pair of rolling bearings 1 are arranged in a back combination. The inner ring 2 of each rolling bearing 1 is fitted to the outer diameter surface of the main shaft 20, and the outer ring 3 is fitted to the inner diameter surface of the bearing box 21. These inner and outer rings 2 and 3 are positioned by an inner ring spacer 18 and an outer ring spacer 17, respectively, and are fixed to a main shaft 20 and a bearing box 21 by an inner ring presser spacer 22 and an outer ring presser cover 23, respectively. Further, a grease tank 10 is disposed on the back side of each rolling bearing 1.

The operation of the lubricating structure having the above configuration will be described.
At the time of assembly, grease is sealed in the rolling bearing 1 and grease is sealed in the grease reservoir 11 of the grease tank 10. The lubrication of the bearing is performed by using the initially charged grease and the grease base oil in the grease tank 10 by extracting and moving the capillarity of the base oil moving medium 15. Specifically, the grease base oil extracted by the base oil moving medium 15 is moved to the outside of the grease reservoir 11 and adheres to the slope 7 a of the circumferential groove 7 of the inner ring 2. The base oil adhering to the inclined surface 7a moves to the inclined surface portion 2b of the inner ring 2 due to the surface tension of the base oil and the centrifugal force accompanying the rotation of the inner ring 2, and further toward the inside of the bearing while adhering to the inclined surface portion 2b. Moving. Since the slope 7a and the slope 2b are connected to a smooth curve, the base oil moves smoothly from the slope 7a to the slope 2b. Further, the clearance δ between the slope portion 2b of the inner ring 2 and the convex portion 13b of the grease tank tip member 13 is small, and the pumping action accompanying the rotation of the inner ring 2 promotes the movement of the base oil along the slope portion 2b. Also, a sealing effect that prevents grease leakage from the inside of the bearing can be expected. The base oil that has reached the boundary edge portion with the rolling surface 2a in the slope portion 2b scatters to the outer diameter side by centrifugal force, adheres to the surface of the rolling element 4 and the inner surface of the pocket 5a of the cage 5, and lubricates. Used as oil.

  When the operation is stopped, the oil adhering to the slope portion 2 b of the inner ring 2 and the oil supplied from the grease in the grease reservoir 11 through the base oil moving medium 15 are temporarily held in the circumferential groove 7. At the time of starting, the inner ring 2 rotates, so that the oil held in the circumferential groove 7 is used again as the lubricating oil. For this reason, it can always lubricate with abundant lubricating oil. Thus, in addition to the initial sealed grease inside the bearing, the grease is contained in the grease reservoir 11, so that the reliability of lubrication is high and the life of the bearing can be extended.

  For example, when the pair of rolling bearings 1 are arranged in a rear combination as in the spindle device of FIG. 5, the grease tank 10 can be arranged on the rear side of each pair of rolling bearings 1. According to this configuration, it is not necessary to provide a lubricating component on the front side of the rolling bearing 1. Therefore, the design from which the distance from the rolling bearing 1 to the one end part 20a which is the tool attachment end of the main shaft 20 becomes the shortest can be performed. If the distance from the rolling bearing 1 to the one end portion 20a of the main shaft 20 is short, the moment stiffness against an external force load acting on the tool can be increased. However, when moment rigidity is not required, the grease tank 10 may be disposed on the front side of the rolling bearing 1.

  Since the base oil of grease sealed in the grease reservoir 11 of the grease tank is used as the lubricating oil, an oil tank and piping are not required outside. There is no need for the bearing box 21 to be processed with high accuracy such as an oil introduction hole. Therefore, the configuration is simple and the device can be manufactured at a low cost. In addition, since a large amount of oil is not used and driving power for lubrication is not required, it is preferable from the viewpoint of energy saving and resource saving. Furthermore, because of grease lubrication, no maintenance is required.

  6 and 7 show different examples of the base oil moving medium 15. As shown in FIG. 7, the portion in the grease reservoir 11 in the base oil moving medium 15 is branched into a plurality of branch portions 15b that are separated from each other in the circumferential direction. In this way, if the grease reservoir 11 of the base oil moving medium 15 is branched into a plurality of branch portions 15 b, the branch portions 15 b can be dispersed and arranged in a wide range of the grease reservoir 11. The base oil can be efficiently extracted from the whole area.

  FIG. 8 shows an example in which the circumferential groove 7 is not provided in the slope portion 2 b of the inner ring 2. The tip of the portion of the base oil moving medium 15 that protrudes from the grease reservoir 11 is in contact with the slope portion 2b. In the case of this embodiment, the base oil extracted from the grease in the grease reservoir 11 by the base oil moving medium 15 adheres to the slope portion 2 b of the inner ring 2. The subsequent steps are the same as described above. It is preferable that the circumferential groove 7 is provided because the action of retaining oil in the circumferential groove 7 is obtained when the operation is stopped as described above, but even if the circumferential groove 7 is not provided, Lubrication reliability is high and bearing life can be extended. If the circumferential groove 7 is not provided, there is an advantage that the inner ring 2 can be easily processed and the inner ring 2 can be manufactured at low cost.

  FIG. 9 shows an example in which a step portion 19 is provided in the inner ring 2 instead of the circumferential groove 7. The step portion 19 includes a step surface 19a that is a surface orthogonal to the bearing center line O following the edge of the slope portion 2b, and a cylindrical surface 19b that extends axially outward from the inner diameter end of the step surface 19a. . The step surface 19a and the slope portion 2b are connected to a smooth curve. In a broad sense, the step surface 19a is a part of the slope portion 2b. The tip of the portion of the base oil moving medium 15 that protrudes from the grease reservoir 11 is in contact with the step surface 19a. In the case of this embodiment, the base oil extracted from the grease in the grease reservoir 11 by the base oil moving medium 15 first adheres to the step surface 19a, and is transmitted from the step surface 19a to the slope portion 2b to be supplied into the bearing. The Even if such a step portion 19 is provided, the reliability of lubrication is high and the life of the bearing can be extended, and the inner ring 2 can be manufactured at a lower cost than the case where the circumferential groove 7 is provided.

  The lubricating structure of the present invention can also be applied when the rolling bearing 1 is a cylindrical roller bearing as shown in FIG. In this embodiment, both sides of the rolling surface 2a on the outer diameter surface of the inner ring 2 are the slope portions 2b, and the circumferential grooves 7 are formed in each slope portion 2b. Grease tanks 10 are disposed on both sides of the rolling bearing 1, and the tip of the base oil moving medium 15 provided in each grease tank 10 is in contact with the inclined surface 7 a on the rolling surface 2 a side of each circumferential groove 7. With this configuration, the same operation and effect as when the rolling bearing 1 is an angular ball bearing can be obtained. In the illustrated example, the grease tank 10 is provided on both sides of the rolling bearing 1, but the grease tank 10 may be provided on only one side as long as the lubrication conditions are satisfied.

  In each of the above embodiments, the lubrication structure of the rolling bearing that supports the machine tool spindle has been described. However, the lubrication structure of the present invention is a bearing other than the machine tool spindle, for example, a bearing used for a motor or a general work machine. It can also be applied to.

DESCRIPTION OF SYMBOLS 1 ... Rolling bearing 2 ... Inner ring 2a ... Rolling surface 2b ... Slope part 3 ... Outer ring 7 ... Circumferential groove 7a ... Inclined surface (side surface)
DESCRIPTION OF SYMBOLS 10 ... Grease tank 11 ... Grease reservoir 13a ... Cylindrical part 14 ... Medium insertion clearance 15 ... Base oil moving medium 15b ... Branch part 19 ... Step part 19a ... Step surface 20 ... Main shaft O ... Bearing center line

Claims (15)

  In addition to providing a slope on the side of the rolling surface on the outer diameter surface of the inner ring of the rolling bearing and a grease tank with an internal grease reservoir located adjacent to the outer ring of the rolling bearing, the grease in this grease tank A base oil moving medium for moving the base oil in the grease by capillary action is provided in the reservoir, and one end of the base oil moving medium is brought into contact with the inclined surface portion, and the base oil in the grease sealed in the grease reservoir is provided. Adheres to the inclined surface portion through the base oil moving medium, and the base oil adhered to the inclined surface portion has the surface tension of the base oil and the attached flow of the base oil along the inclined surface portion caused by the rotation of the inner ring. A lubrication structure for a rolling bearing, characterized in that it is supplied into the bearing.   2. The grease tank according to claim 1, wherein the grease tank has a medium insertion gap that communicates the grease reservoir and the outside, and the base oil moving medium is inserted into the medium insertion gap. An outer diameter side portion of the medium insertion clearance is formed as a cylindrical portion that covers the slope portion of the inner ring through the clearance portion, and protrudes toward the axial center side of the bearing from the medium insertion clearance in the cylindrical portion. A lubricating structure of a rolling bearing having a shape in which a part of an inner diameter surface of the part guides a part of the base oil moving medium outside a grease reservoir so that a tip is in contact with the slope part.   3. The rolling bearing according to claim 1, wherein a circumferential groove having a V-shaped cross section is provided in the slope portion, and one end of the base oil moving medium is brought into contact with the slope of the circumferential groove on the rolling surface side. Lubrication structure.   The lubrication of a rolling bearing according to claim 1 or 2, wherein a step portion having a small diameter on the side far from the rolling surface is provided on the slope portion, and one end of the base oil moving medium is in contact with the step surface of the step portion. Construction. In any one of claims 1 to 4, angle alpha (°) of the inclined surface portion with respect to the bearing center line, a ball pitch circle diameter _d m (mm), the rotational speed and n ^{(min -1)} if you did this,
_{α ≧ {0.056 · (d m} n ^{value) 10-4}} -2
Rolling bearing lubrication structure that satisfies this relationship.   6. The lubrication structure for a rolling bearing according to claim 1, wherein the base oil moving medium is made of Japanese paper.   6. The lubrication structure for a rolling bearing according to claim 1, wherein the base oil moving medium is a cloth.   6. The lubrication structure for a rolling bearing according to claim 1, wherein the base oil moving medium is made of leather.   9. The lubricating structure of a rolling bearing according to claim 1, wherein the base oil moving medium is provided in the grease tank so that a length in a circumferential direction of a contact portion with the slope portion can be adjusted.   10. The lubrication structure for a rolling bearing according to claim 1, wherein a portion in the grease reservoir in the base oil moving medium is branched into a plurality of branch portions separated from each other in the circumferential direction.   11. The rolling bearing lubrication structure according to claim 1, wherein the grease tank is made of steel or resin and is formed by machining.   11. The rolling bearing lubrication structure according to claim 1, wherein the grease tank is made of resin and formed by injection molding.   The lubrication structure for a rolling bearing according to any one of claims 1 to 12, wherein the rolling bearing is an angular ball bearing.   The lubrication structure for a rolling bearing according to any one of claims 1 to 12, wherein the rolling bearing is a cylindrical roller bearing.   15. The lubrication structure for a rolling bearing according to claim 1, wherein the lubricating structure is used for supporting a machine tool spindle.

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