JPH10184705A - Grease feeding device for bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate any additional facilities so as to make maintenance unnecessary, to increase a speed, to prolong a service life and to facilitate quality control by providing an oil sump room in a seat between inner rings and a discharge groove for controlling a discharge oil amount in an end surface contacted with the inner ring so as to be extended from the midway of a radial direction to an outer diameter edge and communicating this groove with the oil sump room. SOLUTION: A seat 6 between inner rings is composed of an outer peripheral part item 8, an inner part item 9 and a sealing member 10 and provided so as to be pressed to the end surface 2a of an inner ring 2 within the width of a rolling element 4. An oil sump room 11 is provided in the inner diameter surface of the outer peripheral part item 8 so as to have a circumferential groove with a width extended to the vicinity of both ends thereof. For a discharge groove 12 provided in both side end surfaces of the seat 6 between the inner rings, a small hole communication route 13 extended from the midway of an end surface radial direction to an outer diameter edge 13 penetrated through the flange part 8a of the outer peripheral part item 8 and communicated with the small hole 14 of the oil sump room 11. Oil is pressure-fed by the centrifugal force of the seat 6 between the inner rings rotated together with the inner ring 2 and its flow rate is controlled to execute lubrication. Thus, lubrication is performed with maintenance unnecessary.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing lubrication device applied to a bearing requiring high speed and long life, such as a main shaft of a machine tool.

[0002]

2. Description of the Related Art Grease lubrication is often used for this type of bearing in terms of cost and maintenance-free. However, speeding up and extending the life of the bearing by grease lubrication are conflicting performances, and it is difficult to achieve both. The speed of machine tool spindles has been increasing due to demands for improvements in productivity and processing accuracy. To operate bearings at high speed,
The lubrication method largely depends on the lubrication method, and a lubrication method such as air oil lubrication, jet lubrication, and underrace lubrication may be selected. However, these lubrication methods require additional equipment such as a lubricating device, and have the disadvantage of increasing costs. Therefore, what is desired is a high-speed lubrication method that is inexpensive and maintenance-free. FIG. 11 shows one of the ideas for increasing the life of a grease lubrication machine at high speed. This is an inner race spacer 5 composed of two parts 51a and 51b.
In FIG. 1, a lubricant reservoir 52 is formed inside the spacer, and grease is sealed therein. Lubricating oil (base oil of grease) necessary for operation is supplied to the bearing by the generated minute gap.

[0003]

In the prior art shown in FIG. 11, the amount of oil during operation is controlled by the rotational speed of the bearing (the centrifugal force acting on the grease) and the surface of the fitting portion 53 of the two-piece parts 51a and 51b. This is performed with a small clearance caused by roughness.
For this reason, in order to accurately control the oil amount, it is important to manage the roughness of the fitting surfaces of the two-piece parts 51a and 51b and to manage the interference at the time of fitting. However, it is very difficult to control the roughness and the interference, and it is impossible to cope with mass production. The base oil in the grease is used as the lubricating oil used in the conventional example of FIG. That is, only about 30% of the lubricant in the lubricant reservoir 52 can be used as lubricating oil,
In order to extend the life, it is necessary to increase the space of the lubricant reservoir 52.

[0004] The present invention solves the above-mentioned problems, and enables maintenance-free oil lubrication without requiring additional facilities, enables high-speed and long-life bearings, and facilitates quality control. An object of the present invention is to provide a greasing device for a bearing.

[0005]

According to a first aspect of the present invention, there is provided a lubricating device for a bearing, wherein an oil reservoir is provided in an inner race spacer which is in contact with an end surface of the inner race. A discharge groove for controlling a discharge oil amount at the time of rotation is provided on an end face in contact with the inner ring so as to extend from an intermediate portion in the radial direction to an outer diameter edge. A communication passage is provided between the oil reservoir and the discharge groove to communicate with each other.

According to this configuration, centrifugal force is generated in the oil sealed in the oil reservoir by rotating the spacer, and pressure is generated. By this pressure, the oil is pressure-fed from the communication passage to the discharge groove. The pressure-fed oil is flow-controlled in the discharge groove, discharged toward the rolling elements, and provided for lubrication. The amount of oil discharged from the discharge groove is determined by the rotation speed, the viscosity of the used oil, and the shape of the discharge groove. Specifically, the rotation speed affects the centrifugal force generated in the oil during operation, and this affects the pressure in the oil sump chamber and affects the amount of discharged oil. Therefore, the amount of lubricating oil can be adjusted according to the bearing rotation speed, and the speed of the bearing can be increased. The shape of the discharge groove is determined by the groove depth, groove width, groove length, and the like. In this way, the amount of oil discharged can be controlled by the shape of the discharge groove,
In addition, since the groove shape can be easily processed with higher precision than in the case of surface roughness adjustment and hole drilling, quality control is easy, and accurate small amount supply can be performed. Also, unlike the case where grease base oil is used, most of the oil sump chamber can be used for storing the oil actually used for lubrication, and the oil sump is filled without making the oil sump chamber larger. A long life can be achieved by securing the amount of oil.

In the above structure, the inner race spacer is composed of an outer peripheral part and an inner peripheral part fitted to the inner periphery of the outer peripheral part, and the oil reservoir is formed on an inner diameter surface of the outer peripheral part. It is good. Thereby, the inner ring spacer having the oil reservoir can be easily formed.

In these configurations, the end surface of the inner race that comes into contact with the inner race spacer may be inside the width of the rolling element. Thereby, the opening position of the discharge groove of the inner ring spacer approaches the rolling element, and the oil discharged from the discharge groove easily spreads to the rolling element. In the case of angular contact ball bearings, etc., due to the contact angle generated between the inner ring and the rolling element, even if the inner ring width is reduced so that one end face of the inner ring is inside the width of the rolling element, the function as the inner ring is not impaired. .

The present invention can also be applied to a case where two bearings are provided side by side, for example, by adopting the following configuration. Two bearings having an inner ring whose one end face is inside the width of the rolling element are provided side by side in the same direction. Of the inner ring end faces within these rolling element widths, an inner ring spacer having an oil reservoir for sealing oil is provided in contact with an end face of an inner ring in which the inner rings are not adjacent to each other. A seat is provided. Discharge grooves for controlling the discharge oil amount during rotation are provided on the end faces of the respective inner ring spacers, which are in contact with the inner ring end faces within the rolling element width, so as to extend from an intermediate portion in the radial direction to the outer diameter edge. A communication passage communicating from the oil sump chamber to the minute groove closer to the oil sump chamber is provided in the inner ring spacer with the oil sump chamber, and a communication passage is provided in the minute groove far from the oil sump chamber to the oil sump chamber. The communicating passages are provided in the inner ring spacer with the oil reservoir, the inner ring, and the oil passage forming spacer. In the case of this configuration, even if the inner ring spacer having a long axial length can be provided only on one of the two bearings provided side by side, each of the two rows of bearings is provided from the inner ring spacer with one oil reservoir. Oil can be supplied from the discharge groove. Therefore, like a spindle device of a machine tool or the like, a bearing arrangement portion is provided at two places separated in the axial direction,
The present invention can be applied to an apparatus in which a plurality of bearings are provided in one or both bearing arrangement portions.

Further, in the configuration of the first aspect, the outer peripheral surface portion between the end surface of the inner race on the side of the inner race spacer with the oil reservoir and the raceway surface may be formed as a tapered surface having a small diameter on the end surface side. . As a result, the oil discharged from the discharge groove flows while adhering from the inner ring end surface to the tapered surface due to the surface tension of the oil, scatters near the raceway surface of the inner ring, and is provided as lubricating oil. Therefore, the oil discharged from the discharge groove is supplied to the rolling elements satisfactorily, and the lubricity is improved. Also, for this reason, oil can be supplied from the discharge groove without making the inner ring width a special width such that the end face is within the width of the rolling element, and the bearing greasing device is applied to various types of bearings. can do.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. A ring-shaped inner ring spacer 6 and an outer ring spacer 7 are provided between the inner rings 2 and 2 and between the outer rings 3 and 3 of the pair of bearings 1 and 1 arranged apart from each other.
Each bearing 1 is composed of an angular ball bearing composed of an inner ring 2, an outer ring 3, a rolling element 4, and a retainer 5, and is provided back to back. The inner ring 2 of each bearing 1 has one end face 2a (farther from the point of action deviated by the contact angle) having a rolling element 4
Is formed inside the width W.

The inner race spacer 6 is provided such that both ends are pressed against an end face 2a of the inner races 2, 2 within the rolling element width. The inner race spacer 6 includes an outer peripheral component 8, an inner peripheral component 9, and a sealing member 10. A circumferential groove-shaped oil reservoir 11 having a groove width extending to near both ends of the outer peripheral component 8 is provided on the inner diameter surface of the outer peripheral component 8. Is formed. Lubricating oil is sealed in the oil reservoir 11. The seal member 10 is made of an elastic body such as an O-ring,
Annular flanges 8a left at both ends of the inner diameter of the outer peripheral part 8
The inner and outer parts 9 and
Prevents leakage of lubricating oil from between 8 spaces.

On both end faces of the inner ring spacer 6, discharge grooves 12 are provided.
Is provided extending in the radial direction from a radially intermediate portion of the end face to the outer diameter edge, and a small-hole-shaped communication passage 13 communicating with the discharge groove 12 penetrates the flange-shaped portion 8 a of the outer peripheral component 8. It is provided. The discharge groove 12 is provided at one or more positions in the circumferential direction of the inner ring spacer 6. In this example, one discharge groove 12 is provided for each bearing 1, that is, one discharge groove is provided at each end of the inner ring spacer 6, and the discharge grooves 12 at both ends are positioned 180 ° apart from each other. The shape of the ejection groove 12 is, for example, a groove having a minute depth such that the groove width is on the order of millimeters and the groove depth is on the order of microns. The inner peripheral part 9 is formed with a small hole 14 serving as a lubricating oil filling port for opening the oil reservoir chamber 11 on the inner diameter surface side.

The operation of the above configuration will be described. Oil reservoir 11
When the inner ring spacer 6 rotates together with the inner ring 2, a centrifugal force is generated in the oil sealed in the, and pressure is generated. By this pressure, the oil is pressure-fed from the communication passage 13 to the discharge groove 12. The flow rate of the pumped oil is controlled by the discharge groove 12,
It is discharged toward the rolling elements 4 and provided for lubrication. The oil amount control during operation can be performed by the rotational speed (centrifugal force generated in the oil amount during operation), the viscosity of the used oil, and the shape design of the discharge groove 12. Here, the discharge oil amount can be obtained by Darcy's formula, and can be obtained by the following relational formula.

Q = P · a · b ³ · X / 4 · μ · L Q: Discharge oil amount P: Pressure in oil sump during operation a: Groove depth / 2 (see FIG. 2) b: Groove width / 2 (see FIG. 2) X: constant μ: oil viscosity L: groove length (see FIG. 2) The groove length L is an effective length, which is the length from the center of the opening of the communication passage 13 to the groove end. It will be.

FIG. 3 shows an example of a spindle device such as a machine tool or an industrial machine incorporating the bearing greasing device of FIG. The bearings 1 on both sides and the inner race spacer 6 therebetween are fitted on the outer periphery of a shaft 15 serving as a spindle.
The inner ring spacer 6 is fixed by being sandwiched between a step surface 15 a of the shaft 15 and a nut 16 screwed to the threaded portion of the shaft 15. The outer ring 3 and the outer ring spacer 7 of the dual bearing 1 are fitted to the cylindrical inner diameter surface of the housing 17, and
7 are fastened and fixed between ring-shaped holding members 18 fixed to both ends by bolts or the like. As described above, the greasing device for the bearing can be effectively used when the inner ring spacer 6 is provided between the bearings 1 and 1 of the spindle device which are arranged apart from each other.

FIG. 4 shows another example of a spindle device to which the bearing lubrication device of the present invention is applied. This example is a configuration example of a parallel back combination of angular contact ball bearings which is a general bearing arrangement of a machine tool. In this bearing arrangement, the two inner bearings 1 and the two outer bearings 1A have the same configuration as in the example of FIG. 1, and one end face 2a of the inner ring 2 has a width W of the rolling element 4. It is inside. The inner ring end faces 2a of these bearings 1 and 1A face each other inward. The inner ring spacer 6A with the oil sump
Both ends are provided between the inner rings 2 of the bearings 1 so as to be pressed against the end face 2a. An oil passage forming inner ring spacer 19 is provided between the inner bearing 1 and the inner ring 2 of the outer bearing 1A.

The inner ring spacer 6A with the oil reservoir has a circumferential groove-shaped oil reservoir 11A on the inner diameter surface.
A discharge groove 12 and a communication passage 13 are formed at both ends to supply oil to the two inner bearings 1 and 1 (only the discharge groove at one end is shown in the figure). For each of the two outer bearings 1A, a discharge groove 12A similar to the discharge groove 12 of the inner race spacer 6A with an oil reservoir is provided in each oil passage forming inner race spacer 19, and an inner race spacer with an oil reservoir chamber is provided. 6A oil reservoir 11A to discharge groove 1
Oil is supplied through a communication passage 13A communicating with 2A. The communication passage 13A for the outer bearing is provided with a communication passage portion 13Aa provided in the flange portion 6a of the inner race spacer 6A with the oil reservoir, the inner race 2 of the inner bearing 1, and the inner race spacer 19 for forming the oil passage. , 13A
b, 13Ac. These communication passage portions 13A
A seal member 21 made up of an O-ring is provided at a connection between a, 13Ab, and 13Ac. In addition, the inner ring spacer 6A of this example has a configuration in which the inner peripheral part 9 of the example of FIG. It consists of.
In the inner ring spacer 6A, the oil is sealed in the oil reservoir 11A by being fitted around the shaft 15 and sealed with the seal member 10. The inner ring spacer 6A is provided with an oil inlet 22 with a plug on the outer diameter surface, and performs an operation of sealing oil from the outer diameter surface into the oil reservoir 11A. The outer ring spacer 7 is provided with an injection nozzle insertion hole 23 corresponding to the oil injection port 17.

In the case of the lubricating apparatus having this configuration, oil can be supplied from the discharge grooves 12, 12A to the inner and outer rows of bearings 1, 1A from the inner ring spacer 6A with one oil reservoir. For this reason, a bearing arrangement in which a sufficient capacity oil reservoir is not provided between the inner and outer bearings 1 and 1A is provided, but a plurality of rows are provided for each of the four rows.
A sufficient amount of oil can be supplied to the individual bearings 1 and 1A, and the life can be improved.

FIGS. 5 and 6 show another embodiment of the present invention. In this example, the width of the inner ring 2 is increased to be the same as the width of the outer ring in the bearing lubrication device of FIG. 1, and the grooved raceway surface 2 b on the outer diameter surface of the inner ring 2 and the oil sump chamber are provided. An outer diameter surface portion between the end surface 2a of the spacer 6 and the end surface 2a is formed as a tapered surface 2c having a small diameter on the end surface 2a side. Outer diameter dimension Db of side edge of tapered surface 2c on end surface 2a side
Is larger than the outer diameter dimension Ds of the inner ring spacer 6, and the gradient of the tapered surface 2c is a predetermined gradient α. in this way,
(Inner ring outer diameter dimension (Db))> (Inner ring spacer outer diameter dimension Ds with oil reservoir chamber) and the inner ring outer diameter surface is tapered surface 2c to discharge from inner ring spacer 6 with oil reservoir chamber. Due to the surface tension of the oil, the flowing oil flows (arrow s) while adhering from the inner ring end surface to the tapered surface 2c, scatters near the raceway surface 2b, and is used for lubrication. This adhesion flow is caused by the tapered surface 2c.
And is caused, for example, by setting α> 5 °. Thus, the flow of the oil discharged from the inner race spacer 6 with the oil reservoir can be controlled, and effective lubrication can be performed.

An experiment was conducted on the lubricating device applied to the angular ball bearing shown in FIG.
A 100% adhesion flow could be confirmed. Number of revolutions: 8000 rpm Inner ring inner diameter: 100 mm Ds: 116 mm Db: 117 mm α: 5 ° or more Length of tapered surface: 10 mm

FIG. 7 shows an example in which this adhesion flow is used and applied to a greasing device for a cylindrical roller bearing. Cylindrical roller bearing 1
C is composed of an inner ring 2C with both flanges, an outer ring 3C without a flange, rollers 4C as rolling elements, and a retainer 5C. Each of the bearings 1C is in contact with the end face on both sides of the inner ring 2C, and has an oil sump chamber 11, a discharge groove 12,
An inner ring spacer 6 having a communication passage 13 is provided. The outer diameter surface of the flange portion of the inner ring 2C is a tapered surface 2Cc. In the case of this configuration, the oil discharged from the inner race spacer 6 with the oil reservoir chamber adheres to the tapered surface 2Cc from the inner race end surface, and finally flows to the roller end surface and to the cage inner diameter surface. And serve as lubricating oil. In this way, by utilizing the adhesion flow, the minute amount greasing mechanism including the inner ring spacer 6 with the oil reservoir and the discharge groove 12 can be used without making the inner ring width a special width. Therefore, it can be applied to various types of bearings, and it can be expected that the maintenance-free high speed and long life of the bearings can be achieved.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a description will be given of a design method and a groove processing method in an oil supply device according to the present invention. This lubricating device can be designed using the Darcy's formula based on the bearing size, the arrangement and arrangement of the bearings, the number of revolutions, the viscosity of the used oil, the required amount of lubricating oil, and the operation time. FIG. 9 is a design example of the bearing configuration of FIGS. 1 to 3 and shows the relationship between the operating time and the amount of oil discharged per unit time. The design conditions are as follows. Oil reservoir chamber inner diameter Di 104mm Oil reservoir outer diameter De 110mm Oil reservoir chamber width B 60mm Discharge groove width 2.b 1.5mm Discharge groove depth 2.a 0.002mm Discharge groove length L 3.5mm communication passage Number 2 kinematic viscosity of oil 22 cSt Specific gravity of oil 0.9 Number of revolutions 10,000rpm

As the design conditions, for example, the required operation time is 8000 hours, and the required amount of lubricating oil is 1 mg per bearing.
/ H, it is sufficient to find a groove shape that gives a discharge rate of 14.5 mg / h when the oil is full. That is, the groove shape in this example is b = 1.5 mm, d = 0.002 mm, L =
It may be 3.5 mm. As described above, the important point of the design in the greasing device is the groove shape, and particularly, the management of the depth of the discharge groove 12 is important. In the present invention, the groove processing is performed by etching, and the depth can be easily and accurately controlled by adjusting the etching time.
For reference, FIG. 10 shows the relationship between the etching processing time and the groove depth, and a groove depth proportional to the processing time is obtained. In this way, by controlling the processing time,
The groove depth of the discharge groove 12 having a minute depth can be accurately processed.

[0025]

According to the lubricating device for a bearing of the present invention, an oil reservoir is provided in an inner race spacer that is in contact with an end surface of an inner race, and an oil discharge amount during rotation is provided on an end surface of the inner race spacer that contacts the inner race. Are provided, the following effects can be obtained. Maintenance-free oil lubrication is possible without using ancillary equipment. Therefore, a break-in operation at the beginning of the operation such as at the time of grease lubrication becomes unnecessary. Since the amount of lubricating oil can be adjusted according to the bearing speed,
It is possible to increase the speed of the bearing. Since the entirety of the oil sump chamber is used for actual lubrication, the lubrication life of the bearing is determined by the capacity of the oil sump chamber, and proper design of the oil sump chamber enables a bearing design that satisfies the required life.

When the end face of the inner race which is in contact with the inner race spacer with the oil reservoir is inside the width of the rolling element, the oil discharged from the discharge groove is favorably supplied to the rolling element. When two bearings are provided side by side, when the oil is supplied from the same inner ring spacer with an oil reservoir chamber to the discharge groove along the inner ring end face of each bearing as described above, the two bearings are provided side by side. Even when the inner ring spacer from which the oil sump chamber can be obtained can be arranged on only one side, sufficient oil can be supplied to the bearings in both rows. Therefore, application to a spindle device of a machine tool or the like becomes easy. Furthermore, when the outer peripheral surface portion of the inner ring is formed as a tapered surface having a small diameter on the end surface side, the oil discharged from the discharge groove is favorably supplied to the rolling elements without making the inner ring width a special width. . Therefore, the bearing lubrication device can be applied to various types of bearings.

[Brief description of the drawings]

FIG. 1 is a sectional view of a bearing lubrication device according to an embodiment of the present invention.

2A is a partially broken enlarged development view of the bearing inner ring and inner ring spacer seen from the outer diameter side in a portion A of FIG. 1, and FIG. 2B is an enlarged sectional view of the same portion.

FIG. 3 is a cross-sectional view of a spindle device to which the greasing device for the bearing is applied.

FIG. 4 is a partial sectional view of a spindle device to which a bearing greasing device according to another embodiment of the present invention is applied.

FIG. 5 is a cross-sectional view of a bearing greasing device according to still another embodiment of the present invention.

FIG. 6 (A) is a partially enlarged exploded development view of the greasing device,
(B) is an enlarged sectional view of the same part.

FIG. 7 is a cross-sectional view of a greasing device according to still another embodiment.

FIG. 8 is a partially enlarged sectional view of a portion B of the greasing device.

FIG. 9 is a graph showing a relationship between an operation time and an oil discharge amount in an experimental example of the greasing device of FIGS. 1 to 3;

FIG. 10 is a graph showing a relationship between a processing time and a groove depth when a discharge groove is processed by etching.

FIG. 11 is a sectional view of a conventional example.

[Explanation of symbols]

 1, 1A ... bearing 2 ... inner ring 2a ... end face 2c ... taper surface 3 ... end face 6 ... inner ring spacer 8 ... outer peripheral part 9 ... inner peripheral part 10 ... seal material 11 ... oil reservoir chamber 12 ... discharge groove 13 ... communication passage 13A ... communication passage 19 ... inner ring spacer for oil passage formation

Claims (5)

[Claims] An oil reservoir is provided in an inner race spacer in contact with an end surface of an inner race, and a discharge groove for controlling a discharge oil amount during rotation is provided in an end surface of the inner race spacer in contact with the inner race. Is provided extending from the middle part in the radial direction to the outer diameter edge, and a grease supply device for a bearing is provided with a communication passage communicating from the oil reservoir chamber to the minute groove. 2. The inner race spacer comprises an outer peripheral part and an inner peripheral part fitted on the inner periphery of the outer peripheral part, and the oil reservoir is formed on an inner diameter surface of the outer peripheral part. A bearing lubrication device as described. 3. The bearing lubrication device according to claim 1, wherein an end surface of the inner ring that contacts the inner ring spacer is inside a width of the rolling element. 4. Two bearings having an inner ring whose one end face is inside the width of the rolling element are provided side by side in the same direction, and among the inner ring end faces within the rolling element width, the inner ring whose inner rings are not adjacent to each other. In contact with the end face, an inner ring spacer having an oil sump chamber for filling oil is provided, an oil path forming inner ring spacer is provided between the two inner rings, and an inner ring end face of each of the inner ring spacers within the rolling element width. A discharge groove for controlling the discharge oil amount during rotation is provided on the contacting end surface so as to extend from an intermediate portion in the radial direction to an outer diameter edge, and a communication passage communicating from the oil storage chamber to a minute groove closer to the oil storage chamber. Is provided in the inner ring spacer with the oil reservoir, and a communication passage communicating from the oil reservoir to a discharge groove remote from the oil reservoir is provided with the inner ring spacer with the oil reservoir, the inner ring, and A bearing lubrication device provided over the oil passage formation spacer. 5. The bearing lubrication device according to claim 1, wherein an outer peripheral surface portion between the end surface of the inner race on the inner race spacer side and the raceway surface is formed as a tapered surface having a small diameter on the end surface side.