JP2004278645A - Rolling bearing, and main spindle device for machine tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rolling bearing in which temperature pulsation is not generated when grease is supplied, and a main spindle device for a machine tool using that. <P>SOLUTION: In the rolling bearing that is lubricated with grease, a lubricating hole 15 is provided in an outer ring 12. To the rolling bearing 10, grease is supplied through the lubricating hole 15 in such a way that lubrication quantity for one time is 0.004cc-0.1cc. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a rolling bearing used for a main spindle of a machine tool rotating at a high speed, a high-speed motor, and the like, and a spindle device for a machine tool using the same.
[0002]
[Prior art]
Bearings for machine tool spindles are required to have good characteristics such as vibration and sound in order to improve machining accuracy. In addition, bearings for machine tool spindles are required to employ grease lubrication, which is easy to handle and advantageous in terms of environment and cost, and to achieve high-speed rotation and long life.
[0003]
Grease-lubricated rolling bearings used for machine tool spindles are usually lubricated only with grease initially sealed to prevent heat generation. If the grease is sealed at the initial stage and rotated at high speed without performing the grease break-in operation, abnormal heat generation may occur due to the grease getting stuck or stirring resistance. I have to.
[0004]
In recent years, the speed of machine tool spindles has been increasingly increased, and bearings supporting the spindles are rarely used in an environment of dmN (= (bearing inner diameter + bearing outer diameter) ÷ 2 × rotation speed (rpm)) of 1,000,000 or more. Is gone. Compared with oil-lubricated bearings such as oil air and oil mist, grease-lubricated rolling bearings tend to have a shorter life at high speed rotation. In the case of grease lubrication, the bearing is seized due to grease deterioration before the rolling fatigue life of the bearing. If the rotation speed is extremely high, seizure occurs early due to deterioration of grease or insufficient formation of an oil film in a short time.
[0005]
In order to solve this problem, the applicant has disclosed in Japanese Patent Application No. 2002-200172 a grease-lubricated rolling bearing in which a replenishing hole is provided in an outer ring, and a replenishing amount per one time is supplied through the replenishing hole. A rolling bearing has been proposed in which grease is supplied so as to be 0.1 to 4% of the bearing space volume. According to this rolling bearing, abnormal temperature rise of the rotating bearing can be suppressed, and seizure can be prevented. Therefore, according to the rolling bearing described in Japanese Patent Application No. 2002-200172, it is not necessary to avoid the abnormal temperature rise and to perform the running-in operation.
[0006]
[Problems to be solved by the invention]
However, the rolling bearing described in Japanese Patent Application No. 2002-200172 is configured so that abnormal temperature rise does not occur by replenishing grease such that a single replenishment amount is 0.1 to 4% of the bearing space volume. However, if the amount of grease supplied at one time is large, temperature pulsation may occur.
[0007]
An evaluation test was conducted to evaluate the pulsation of this temperature. As a result, in the case of an angular contact ball bearing having an inner diameter of 65 mm, 1% or more of the bearing space volume after one replenishment (1% of the bearing space volume is equivalent to 0.15 cc) It has been found that when grease is replenished, pulsation occurs at a temperature of about 1 ° C. to 2 ° C. at the moment of replenishment.
[0008]
This temperature pulsation is not a problem during normal use where accuracy is not required.However, in a rolling bearing used for a main shaft of a device requiring strict accuracy, such as a machine tool for a die application, the pulsation of this temperature is not caused. As a result, the length of the shaft changes, which may affect the machining accuracy.
[0009]
The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a rolling bearing that does not generate temperature pulsation when supplying grease, and a spindle device for a machine tool using the same.
[0010]
[Means for Solving the Problems]
The object of the present invention is achieved by the following configurations.
(1) A grease-lubricated rolling bearing in which a supply hole is provided in an outer ring, and grease is supplied via the supply hole such that a single supply amount is 0.004 cc to 0.1 cc. Rolling bearing, characterized in that:
(2) The rolling bearing according to (1), wherein the rolling element is a cylindrical roller.
(3) The rolling bearing according to (1), wherein the replenishing hole has a contact angle, the rolling element is a ball, and the replenishing hole is opened at a position on the inner diameter surface of the outer ring that is displaced from the contact portion of the outer ring raceway.
(4) The rolling bearing according to any one of (1) to (3), which is used to support a main shaft of a machine tool and a high-speed motor.
(5) The rolling bearing according to any one of (1) to (4), wherein a diameter of the supply hole is in a range of 0.1 to 5 mm.
(6) The rolling bearing according to any one of (1) to (5), which is used in an environment where dmN is 1,000,000 or more.
(7) A grease-lubricated rolling bearing, wherein an outer ring having an outer raceway on an inner peripheral surface, an inner racer having an inner raceway on an outer peripheral surface, and rolling freely between the outer raceway and the inner raceway. A rolling element provided, and a grease replenishing element for replenishing additional grease in the rolling bearing, wherein the replenishment amount of the additional grease at a time is 0.004 cc to 0.1 cc. A rolling bearing.
(8) The rolling bearing according to (7), wherein the grease supply element is a supply hole provided in the outer ring.
(9) The rolling bearing according to (8), wherein the supply hole is provided in a radial direction.
(10) The rolling bearing according to (8), wherein the supply hole is provided in an axial direction.
(11) The rolling bearing according to (7), further including an outer race spacer, wherein the grease supply element is a supply hole provided in the outer race spacer.
(12) The rolling bearing according to any one of (7) to (11), wherein the rolling element is a cylindrical roller.
(13) The replenishing hole has a contact angle, the rolling element is a ball, and the replenishing hole is opened at a position shifted from a contact portion of the outer raceway on the inner diameter surface of the outer race. The rolling bearing according to any of the above.
(14) The rolling bearing according to any one of (7) to (13), which is used to support a main shaft of a machine tool and a high-speed motor.
(15) The rolling bearing according to any one of (7) to (14), wherein a diameter of the supply hole is in a range of 0.1 to 5 mm.
(16) The rolling bearing according to any one of (7) to (15), which is used in an environment where dmN is 1,000,000 or more.
(17) A spindle device for a machine tool in which a rolling bearing for supporting a main shaft is mounted in a housing, wherein the rolling bearing is grease-lubricated, the rolling bearing includes an outer ring having an outer raceway on an inner peripheral surface, An inner ring having an inner raceway on an outer peripheral surface; a rolling element rotatably provided between the outer raceway and the inner raceway; and a grease replenishing element for replenishing additional grease in the rolling bearing. A spindle device for a machine tool, wherein the additional grease is replenished at a time in a supply amount of 0.004 cc to 0.1 cc.
(18) The spindle device for a machine tool according to (17), wherein the grease element is a supply hole provided in the outer ring.
(19) The spindle device for a machine tool according to (18), wherein the supply hole of the outer ring is provided in a radial direction.
(20) The spindle device for a machine tool according to (18), wherein the supply hole of the outer ring is provided in an axial direction.
(21) The spindle device for a machine tool according to (17), further including an outer race spacer, wherein the grease supply element is a supply hole provided in the outer race spacer.
(22) The spindle device for a machine tool according to (17), wherein the grease supply element is a supply hole provided in a housing.
[0011]
According to the rolling bearing having the above configuration, before the grease is deteriorated early or the bearing is damaged due to insufficient oil film formation, new grease is supplied from the outer ring side (radial direction) or the outer ring spacer side (axial direction). Thus, the bearing life can be extended. When supplied from the outer ring side, the grease is supplied to the bearing space from the inner surface of the outer ring through the supply hole. On the other hand, when the grease is supplied from the outer ring spacer side, the grease is supplied directly to the bearing space in the axial direction through the supply hole. At the time of supply from the outer ring spacer side, it is more preferable to supply grease to the inner diameter side than to the outer diameter. The replenished grease adheres to the rolling elements and the cage, and is adapted to the entire inside of the bearing as the rolling elements and the cage rotate.
[0012]
Normally, in the case of an angular contact ball bearing incorporated in a main shaft of a machine tool, the initial amount of grease to be filled is set to 10 to 20% of the bearing space volume. On the other hand, in the case of a cylindrical roller bearing incorporated in a main shaft of a machine tool, the initial amount of grease to be filled is set to 8 to 15% of the bearing space volume. This comes from the demand for reducing the time required for the initial running-in of grease and for suppressing the temperature rise. In particular, in the case of a cylindrical roller bearing, during the initial running-in operation of the grease, the rotating roller often catches the grease and abnormally rises in temperature. In the worst case, seizure may occur.
[0013]
However, by setting the amount of grease supplied at one time to 0.004 cc to 0.1 cc as in the above configuration, abnormal temperature rise is avoided, and there is no need for running-in. Furthermore, in the rolling bearing having the above-described configuration, the pulsation of the temperature can be suppressed by setting the amount of grease supplied at one time to 0.004 cc to 0.1 cc, and the main body of the machine tool spindle device to which the rolling bearing is applied. Processing accuracy can be maintained at a high level.
[0014]
For example, when the rolling element is a ball having a contact angle, such as an angular ball bearing, a replenishing hole is opened at a position on the inner surface of the outer ring that is displaced from the side where the contact portion of the raceway groove is present. The amount of grease replenishment at one time via the above is set to 0.004 cc to 0.1 cc, thereby preventing damage during operation and pulsation of temperature.
When the diameter of the supply hole is in the range of 0.1 to 5 mm, a fixed amount of grease can be supplied more smoothly. That is, the grease does not clog the supply hole, and the grease is not excessively supplied. The supply hole is not limited to a circular cross section. For example, a supply hole having a rectangular cross section or a polygonal cross section having a cross-sectional area equivalent to a circular cross-sectional area having a diameter of 0.1 to 5 mm may be used.
The rolling bearing can achieve a long life even in an environment where dmN is 1,000,000 or more.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
An angular contact ball bearing 10 according to a first embodiment of the present invention shown in FIG. 1 has an inner race 11 having an inner race 11a on an outer peripheral surface, an outer race 12 having an outer race 12a on an inner peripheral surface, and the inner race 11 and the inner race 11. A plurality of balls 13 arranged along the inner raceway 11a and the outer raceway 12a provided, and a retainer 14 for holding the balls 13 at equal intervals in the circumferential direction. The angular ball bearing 10 of the present embodiment is an outer ring counterbore bearing used for supporting a main shaft of a machine tool.
[0016]
In the present embodiment, a supply hole 15 is provided on the counter bore side (the right side in FIG. 1) of the outer ring 12 as a supply element that penetrates the outer ring 12 in the radial direction. The supply hole 15 has a circular cross section having a diameter of 0.1 to 5 mm. The supply hole 15 is open at a location on the inner diameter surface of the outer ring 12 adjacent to the outer ring raceway 12a.
The supply holes 15 may be provided at a plurality of locations spaced apart in the circumferential direction of the outer ring 12. The supply hole 15 may be provided on the side where the contact portion 12b is located, or may be provided on a portion other than the contact portion 12b.
[0017]
In the bearing space of the angular contact ball bearing 10, grease in an amount of 10 to 20% of the bearing space volume is initially sealed. Here, the bearing space volume means a volume obtained by subtracting the volume of the rolling element and the volume of the cage from the space formed between the inner diameter of the outer ring and the outer diameter of the inner ring. When the bearing is used, the following grease replenishing method is applied. That is, the grease is shot at an appropriate timing (intermittently or periodically) through the supply hole 15 such that the amount of one supply is 0.004 cc to 0.1 cc. In consideration of the grease shot variation, the upper limit of the replenishment amount at one time is 0.12 cc. In addition, the amount of grease supplied at one time is preferably 0.01 cc to 0.03 cc in consideration of prevention of occurrence of temperature pulsation. By performing a grease shot within the above range, it is possible to prevent the occurrence of abnormal temperature rise due to grease deterioration or insufficient oil film formation and damage to the bearing, to suppress temperature pulsation at the time of grease replenishment, and to reduce the angular pulsation of the angular ball bearing 10. It is possible to prevent deterioration of the axis accuracy of the machine tool to which the is attached.
[0018]
The angular ball bearing 20 according to the second embodiment of the present invention shown in FIG. 2 includes an inner ring 21, an outer ring 22, a plurality of balls 23 disposed between an inner ring track 21 a of the inner and outer rings 21 and an outer ring track 22 a of the outer ring 22. A cage 24 is provided for holding the balls 23 at equal intervals in the circumferential direction.
[0019]
In the present embodiment, a supply hole 25 is provided on the counter bore side (the right side in FIG. 2) of the outer ring 22 as a supply element that penetrates the outer ring 22 in the radial direction. A grease reservoir 25a is formed on the outer ring inner diameter surface side of the supply hole 25. The cross-sectional area of the grease reservoir 25a is larger than the cross-sectional areas of other portions of the supply hole 25. Since the supply hole 25 has the grease reservoir 25a, it is a stepped cylindrical space. The grease reservoir 25a is located on the inner surface of the outer ring 22 at a position adjacent to the outer ring track 22a. In other embodiments described below, the supply hole may have a grease reservoir.
[0020]
In the bearing space of the angular contact ball bearing 20, grease in an amount of 10 to 20% of the bearing space volume is initially sealed. When the bearing is used, the following grease replenishing method is applied. That is, the grease is shot at appropriate timing (intermittently or periodically) through the supply hole 25 such that the amount of one replenishment becomes 0.004 cc to 0.1 cc. In consideration of the grease shot variation, the upper limit of the replenishment amount at one time is 0.12 cc. In addition, the amount of grease supplied at one time is preferably 0.01 cc to 0.03 cc in consideration of prevention of occurrence of temperature pulsation. By performing a grease shot within the above range, it is possible to prevent the occurrence of abnormal temperature rise due to grease deterioration or insufficient oil film formation and damage to the bearing, to suppress temperature pulsation at the time of grease replenishment, and to reduce the angular ball bearing 20. It is possible to prevent deterioration of the axis accuracy of the machine tool to which the is attached.
[0021]
An angular contact ball bearing 30 according to a third embodiment of the present invention shown in FIG. A retainer 34 is provided to hold 33 at equal intervals in the circumferential direction. The angular ball bearing 30 of the present embodiment is an inner ring counterbore bearing.
[0022]
In the present embodiment, a replenishing hole 35 as a replenishing element that penetrates the outer ring 32 in the radial direction is opened on the outer ring track 32a of the outer ring 32 and on the side opposite to the side where the contact portion 32b is located (the right side in FIG. 3). ing. Note that the supply hole 35 may be provided on the side where the contact portion 32b is located, or may be provided in a portion other than the contact portion 32b.
[0023]
In the bearing space of the angular ball bearing 30, grease in an amount of 10 to 20% of the bearing space volume is initially sealed. When the bearing is used, the following grease replenishing method is applied. That is, the grease is shot at an appropriate timing (intermittently or periodically) through the supply hole 35 such that the amount of one supply is 0.004 cc to 0.1 cc. In consideration of the grease shot variation, the upper limit of the replenishment amount at one time is 0.12 cc. In addition, the amount of grease supplied at one time is preferably 0.01 cc to 0.03 cc in consideration of prevention of occurrence of temperature pulsation. By performing a grease shot within the above range, it is possible to prevent the occurrence of abnormal temperature rise due to grease deterioration or insufficient oil film formation and damage to the bearing, to suppress temperature pulsation at the time of grease replenishment, and to reduce the angular ball bearing 30. It is possible to prevent deterioration of the axis accuracy of the machine tool to which the is attached.
[0024]
An angular contact ball bearing 40 according to a fourth embodiment of the present invention shown in FIG. A guide retainer 44 is provided. The angular contact ball bearing 40 of the present embodiment is an outer ring counterbore bearing.
In the present embodiment, a supply hole 45 is provided on the counter bore side (the right side in FIG. 4) of the outer ring 42 as a supply element that penetrates the outer ring 42 in the radial direction. The supply hole 45 is open toward a guide surface 44 a on one side (the right side in FIG. 4) of the retainer 44.
[0025]
In the bearing space of the angular contact ball bearing 40, grease in an amount of 10 to 20% of the bearing space volume is initially sealed. When the bearing is used, the following grease replenishing method is applied. That is, the grease is shot at appropriate timing (intermittently or periodically) via the supply hole 45 so that the amount of one supply is 0.004 cc to 0.1 cc. In consideration of the grease shot variation, the upper limit of the replenishment amount at one time is 0.12 cc. In addition, the amount of grease supplied at one time is preferably 0.01 cc to 0.03 cc in consideration of prevention of occurrence of temperature pulsation. By performing a grease shot within the above range, it is possible to prevent abnormal temperature rise due to grease deterioration or insufficient oil film formation and damage to the bearing, to suppress temperature pulsation at the time of grease replenishment, and to reduce the angular ball bearing 40. It is possible to prevent deterioration of the axis accuracy of the machine tool to which the is attached.
[0026]
An angular ball bearing 50 according to a fifth embodiment of the present invention shown in FIG. A guide retainer 54 is provided. The angular ball bearing 50 of the present embodiment is an outer ring counterbore bearing.
In the present embodiment, a supply hole 55 as a supply element that penetrates the outer ring 52 in the radial direction is provided on a side of the outer ring 52 opposite to the counter bore (the left side in the figure). The supply hole 55 is open toward a guide surface 54 a on one side (the left side in the figure) of the retainer 54.
[0027]
In the bearing space of the angular contact ball bearing 50, grease is initially sealed in an amount of 10 to 20% of the bearing space volume. When the bearing is used, the following grease replenishing method is applied. That is, the grease is shot at appropriate timing (intermittently or periodically) through the supply hole 55 so that the amount of one replenishment becomes 0.004 cc to 0.1 cc. In consideration of the grease shot variation, the upper limit of the replenishment amount at one time is 0.12 cc. Further, the amount of grease replenished at one time is preferably 0.01 cc to 0.03 cc in consideration of prevention of occurrence of temperature pulsation in consideration of prevention of occurrence of temperature pulsation. By performing a grease shot within the above range, it is possible to prevent abnormal temperature rise due to grease deterioration or insufficient oil film formation and damage to the bearing, to suppress temperature pulsation at the time of grease replenishment, and to reduce the angular ball bearing 50. It is possible to prevent deterioration of the axis accuracy of the machine tool to which the is attached.
[0028]
The double-row cylindrical roller bearing 60 according to the sixth embodiment of the present invention shown in FIG. 6 is disposed in two rows between an inner ring 61, an outer ring 62, and an inner ring track 61 a of the inner ring 61 and an outer ring track 62 a of the outer ring 62. A cylindrical roller 63 and a retainer 64 for holding the cylindrical rollers 63 in each row at equal intervals in the circumferential direction are provided. The double-row cylindrical roller bearing 60 of the present embodiment is a rolling bearing for supporting a main shaft of a machine tool.
[0029]
In the present embodiment, a supply hole 65 as a supply element penetrating the outer ring 62 in the radial direction is provided at a central portion in the axial direction of the outer ring 62. The supply hole 65 has a circular cross section having a diameter of 0.1 to 5 mm. The supply holes 65 are open to portions of the respective cages 64 located between the two rows of cylindrical rollers 63.
In the present embodiment, a groove 65b communicating with the supply hole 65 is provided at the axial center of the outer ring outer diameter surface so that the grease G can be easily shot into the supply hole 65, but even if the groove 65b is not provided. Good.
[0030]
Grease is initially sealed in the bearing space of the cylindrical roller bearing 60 in an amount of 8 to 15% of the bearing space volume. When the bearing is used, the following grease replenishing method is applied. That is, the grease G is shot through the supply hole 65 at an appropriate timing (intermittently or periodically) such that the amount of one supply is 0.004 cc to 0.1 cc per line. In consideration of the grease shot variation, the upper limit of the replenishment amount at one time is 0.12 cc. In addition, since cylindrical roller bearings are more likely to cause temperature pulsation than angular ball bearings, the amount of replenishment at one time needs to be smaller than the amount of replenishment to angular ball bearings. Therefore, in the case of a cylindrical roller bearing, it is particularly preferable that the amount of grease supplied once per row is 0.005 cc to 0.02 cc.
[0031]
The grease G shot toward the retainer 64 is uniformly applied on the circumference of the raceway surface of the inner and outer rings as the bearing rotates. In this way, a new oil film is formed by the shot grease G. Except for the minimum required grease, it is scraped out to the outside of the rolling surface to form a bank-like shape. A small amount of base oil leaks from the grease in that state, and the rolling surface and the retainer guide surface are lubricated. By performing a grease shot within the above-described range, it is possible to suppress temperature pulsation at the time of grease replenishment, and to prevent deterioration in shaft accuracy of a machine tool to which the double-row cylindrical roller bearing 60 is attached.
[0032]
The double-row cylindrical roller bearing 70 of the seventh embodiment according to the present invention shown in FIG. 7 is arranged in two rows between an inner race 71, an outer race 72, and an inner raceway 71a of the inner race 71 and an outer raceway 72a of the outer race 72. A cylindrical roller 73 and a retainer 74 for holding the cylindrical rollers 73 in each row at equal intervals in the circumferential direction are provided.
In the present embodiment, the outer ring 72 is provided with a plurality (two in this case) of supply holes 75 as supply elements penetrating the outer ring 72 in the radial direction as viewed in the axial direction. The supply holes 75 open toward the rolling surfaces of the cylindrical rollers 73 in each row. Two rows of grooves 75b are provided on the outer surface of the outer ring.
[0033]
In the bearing space of the cylindrical roller bearing 70, grease in an amount of 8 to 15% of the bearing space volume is initially sealed. When the bearing is used, the following grease replenishing method is applied. That is, at appropriate timing (intermittently or periodically), the grease G is shot through the supply holes 75 such that the supply amount per line is 0.004 cc to 0.1 cc. In consideration of the grease shot variation, the upper limit of the replenishment amount at one time is 0.12 cc. Cylindrical roller bearings are more susceptible to temperature pulsations than angular ball bearings, so the amount of replenishment at one time must be smaller than the amount of replenishment to the angular ball bearing. Therefore, in the case of a cylindrical roller bearing, it is particularly preferable that the amount of grease supplied once per row is 0.005 cc to 0.02 cc. By performing grease shots within the above range, it is possible to prevent abnormal temperature rise due to grease deterioration or insufficient oil film formation and damage to bearings, suppress temperature pulsation during grease replenishment, and provide a double row cylindrical roller. It is possible to prevent deterioration of the shaft accuracy of the machine tool to which the bearing 70 is attached.
[0034]
The single row cylindrical roller bearing 80 according to the eighth embodiment of the present invention shown in FIG. 8 includes an inner ring 81, an outer ring 82, and a plurality of cylindrical rollers disposed between an inner ring track 81a of the inner ring 81 and an outer ring track 82a of the outer ring 82. 83 and an outer ring guide retainer 84 are provided.
In the present embodiment, the outer ring 82 is provided with two supply holes 85 as supply elements that penetrate the outer ring 82 in the radial direction as viewed in the axial direction. Each supply hole 85 opens toward the guide surface of the retainer 84 located on both axial sides of the cylindrical roller 83. Two rows of grooves 85b are provided on the outer diameter surface of the outer race.
Although not shown, a configuration in which one supply hole as viewed in the axial direction, which opens toward one of the cage guide surfaces, may be provided.
[0035]
Grease is initially sealed in the bearing space of the cylindrical roller bearing 80 in an amount of 8 to 15% of the bearing space volume. When the bearing is used, the following grease replenishing method is applied. That is, the grease G is shot through the supply hole 85 at an appropriate timing (intermittently or periodically) so that the amount of one supply is 0.004 cc to 0.1 cc. In consideration of the grease shot variation, the upper limit of the replenishment amount at one time is 0.12 cc. Cylindrical roller bearings are more susceptible to temperature pulsations than angular ball bearings, so the amount of replenishment at one time must be smaller than the amount of replenishment to the angular ball bearing. Therefore, in the case of a cylindrical roller bearing, it is particularly preferable that the amount of grease supplied at one time is 0.005 cc to 0.02 cc. Performing a grease shot within the above range prevents the occurrence of abnormal temperature rise and bearing damage due to grease deterioration or insufficient oil film formation, suppresses temperature pulsation during grease replenishment, and reduces the number of single-row cylindrical rollers. It is possible to prevent the shaft accuracy of the machine tool to which the bearing 80 is attached from deteriorating.
[0036]
The single row cylindrical roller bearing 90 of the ninth embodiment according to the present invention shown in FIG. 9 includes an inner ring 91, an outer ring 92, and a plurality of cylindrical rollers disposed between an inner ring track 91a of the inner ring 91 and an outer ring track 92a of the outer ring 92. 93 and an outer ring guide retainer 94.
In the present embodiment, a supply hole 95 as a supply element that penetrates the outer ring 92 in the radial direction is provided at the axial center of the outer ring 92. The supply hole 95 opens toward the rolling surface of the cylindrical roller 93. A groove 95b is provided at the axial center of the outer ring outer diameter surface.
[0037]
Grease is initially sealed in the bearing space of the cylindrical roller bearing 90 in an amount of 8 to 15% of the bearing space volume. When the bearing is used, the following grease replenishing method is applied. That is, the grease G is shot at appropriate timing (intermittently or periodically) through the supply hole 95 such that the amount of one supply is 0.004 cc to 0.1 cc. In consideration of the grease shot variation, the upper limit of the replenishment amount at one time is 0.12 cc. Cylindrical roller bearings are more susceptible to temperature pulsations than angular ball bearings, so the amount of replenishment at one time must be smaller than the amount of replenishment to the angular ball bearing. Therefore, in the case of a cylindrical roller bearing, it is particularly preferable that the amount of grease supplied at one time is 0.005 cc to 0.02 cc. Performing a grease shot within the above range prevents the occurrence of abnormal temperature rise and bearing damage due to grease deterioration or insufficient oil film formation, suppresses temperature pulsation during grease replenishment, and reduces the number of single-row cylindrical rollers. It is possible to prevent deterioration of the shaft accuracy of the machine tool to which the bearing 90 is attached.
[0038]
The single row cylindrical roller bearing 100 of the tenth embodiment of the present invention shown in FIG. 10 includes an inner ring 101, an outer ring 102, a plurality of cylindrical rollers 103 arranged between an inner ring track 101a of the inner ring 101 and an outer ring track 102a of the outer ring 102, and An outer ring guide retainer 104 is provided.
In the present embodiment, the outer ring 102 is provided with two supply holes 105 as supply elements penetrating the outer ring 102 in the radial direction as viewed in the axial direction. Each replenishing hole 105 is opened between the axial end surfaces of the cylindrical roller 103 and the guide surface of the retainer 104. Two rows of grooves 105b are provided on the outer surface of the outer race.
Although not shown, a configuration in which one supply hole is provided in the radial direction may be employed.
[0039]
In the bearing space of the cylindrical roller bearing 100, grease is initially sealed in an amount of 8 to 15% of the bearing space volume. When the bearing is used, the following grease replenishing method is applied. That is, the grease G is shot through the supply hole 105 at an appropriate timing (intermittently or periodically) so that the amount of one supply is 0.004 cc to 0.1 cc. In consideration of the grease shot variation, the upper limit of the replenishment amount at one time is 0.12 cc. Cylindrical roller bearings are more susceptible to temperature pulsations than angular ball bearings, so the amount of replenishment at one time must be smaller than the amount of replenishment to the angular ball bearing. Therefore, in the case of a cylindrical roller bearing, it is particularly preferable that the amount of grease supplied at one time is 0.005 cc to 0.02 cc. Performing a grease shot within the above range prevents the occurrence of abnormal temperature rise and bearing damage due to grease deterioration or insufficient oil film formation, suppresses temperature pulsation during grease replenishment, and reduces the number of single-row cylindrical rollers. Deterioration of the shaft accuracy of the bearing 100 can be prevented.
[0040]
The single row cylindrical roller bearing 110 according to the eleventh embodiment of the present invention shown in FIG. 11 includes an inner ring 111, an outer ring 112, a plurality of cylindrical rollers 113 disposed between an inner ring raceway 111a of the inner ring 111 and an outer ring raceway 112a of the outer ring 112, and An outer ring guide retainer 114 is provided.
In the present embodiment, a supply hole 115 is provided at the axial center of the outer ring 112 as a supply element that penetrates the outer ring 112 in the radial direction. The supply hole 115 has a tapered shape corresponding to the tapered end of the nozzle 400 that shots grease, and the diameter decreases from the outer diameter surface side toward the inner diameter surface side. That is, the supply hole 115 is a frustoconical space. The supply hole 115 opens toward the rolling surface of the cylindrical roller 113.
[0041]
Grease is initially sealed in the bearing space of the cylindrical roller bearing 110 in an amount of 8 to 15% of the bearing space volume. When the bearing is used, the following grease replenishing method is applied. That is, the grease G is shot via the supply hole 115 at an appropriate timing (intermittently or periodically) so that the amount of one supply is 0.004 cc to 0.1 cc. In consideration of the grease shot variation, the upper limit of the replenishment amount at one time is 0.12 cc. Cylindrical roller bearings are more susceptible to temperature pulsations than angular ball bearings, so the amount of replenishment at one time must be smaller than the amount of replenishment to the angular ball bearing. Therefore, in the case of a cylindrical roller bearing, it is particularly preferable that the amount of grease supplied at one time is 0.005 cc to 0.02 cc. Performing a grease shot within the above range prevents the occurrence of abnormal temperature rise and bearing damage due to grease deterioration or insufficient oil film formation, suppresses temperature pulsation during grease replenishment, and reduces the number of single-row cylindrical rollers. It is possible to prevent the shaft accuracy of the machine tool to which the bearing 110 is attached from deteriorating.
[0042]
The single-row cylindrical roller bearing 120 according to the twelfth embodiment shown in FIG. 12 includes an inner race 121, an outer race 122 having two flanges 122 b, and an inner race 121 a of the inner race 121 and an outer race 122 a of the outer race 122. A cylindrical roller 123 and an outer ring guide retainer 124 are provided.
[0043]
The cylindrical rollers 123 are arranged to be rollable along an outer raceway 122 a formed between the flanges 122 b, which is an inner peripheral surface of the outer race 122, and an inner raceway 121 a formed on the outer peripheral surface of the inner race 121. At both ends of the outer raceway 122a, relief portions 122c, which are concave portions, are provided at positions facing the edge portions 123a of the cylindrical rollers 123, so that interference with the edge portions 123a is avoided.
[0044]
In the present embodiment, one supply hole 125 is formed as a supply element that penetrates the outer ring 122 in the radial direction and communicates with one of the escape portions 122c of the outer ring 122. The additional grease is replenished from the outside to the relief portion 122c inside the rolling bearing 120 through the replenishing hole 125 in the radial direction.
[0045]
The bearing space of the cylindrical roller bearing 120 is initially filled with grease in an amount of 8 to 15% of the bearing space volume. When the bearing is used, the following grease replenishing method is applied. That is, the grease G is shot at appropriate timing (intermittently or periodically) through the supply hole 125 such that the amount of one supply is 0.004 cc to 0.1 cc. The replenished grease is adapted to the whole inside of the bearing with the rolling of the cylindrical roller 123 and makes up for the insufficient grease.
[0046]
In consideration of the grease shot variation, the upper limit of the replenishment amount at one time is 0.12 cc. Cylindrical roller bearings are more susceptible to temperature pulsations than angular ball bearings, so the amount of replenishment at one time must be smaller than the amount of replenishment to the angular ball bearing. Therefore, in the case of a cylindrical roller bearing, it is particularly preferable that the amount of grease supplied at one time is 0.005 cc to 0.02 cc. Performing a grease shot within the above range prevents the occurrence of abnormal temperature rise and bearing damage due to grease deterioration or insufficient oil film formation, suppresses temperature pulsation during grease replenishment, and reduces the number of single-row cylindrical rollers. It is possible to prevent the shaft accuracy of the machine tool to which the bearing 120 is attached from deteriorating.
[0047]
A single-row cylindrical roller bearing 130 according to the thirteenth embodiment of the present invention shown in FIG. 13 is disposed between an inner ring 131, an outer ring 132 having two flanges 132b, and an inner ring track 131a of the inner ring 131 and an outer ring track 132a of the outer ring 132. Provided are two cylindrical rollers 133 and an outer ring guide retainer 134.
[0048]
The cylindrical roller 133 is arranged to be rollable along an outer raceway 132a formed between a flange 132b which is an inner circumferential surface of the outer race 132 and an inner raceway 131a formed on an outer circumferential surface of the inner race 131. At both ends of the outer raceway 132a, relief portions 132c, which are concave portions, are provided at positions facing the edge portions 133a of the cylindrical rollers 133, so that interference with the edge portions 133a is avoided.
[0049]
In the present embodiment, two supply holes 135 are formed as supply elements that penetrate the outer ring 132 in the radial direction and communicate with the respective escape portions 132c of the outer ring 132. The additional grease is supplied from outside to the relief portion 132c inside the rolling bearing 130 in the radial direction via the supply hole 135.
[0050]
Grease is initially sealed in the bearing space of the cylindrical roller bearing 130 in an amount of 8 to 15% of the bearing space volume. When the bearing is used, the following grease replenishing method is applied. That is, the grease G is shot at appropriate timing (intermittently or periodically) through the supply hole 135 such that the amount of one supply is 0.004 cc to 0.1 cc. The replenished grease is adapted to the whole inside of the bearing with the rolling of the cylindrical roller 133, and makes up for the insufficient grease.
[0051]
In consideration of the grease shot variation, the upper limit of the replenishment amount at one time is 0.12 cc. Cylindrical roller bearings are more susceptible to temperature pulsations than angular ball bearings, so the amount of replenishment at one time must be smaller than the amount of replenishment to the angular ball bearing. Therefore, in the case of a cylindrical roller bearing, it is particularly preferable that the amount of grease supplied at one time is 0.005 cc to 0.02 cc. Performing a grease shot within the above range prevents the occurrence of abnormal temperature rise and bearing damage due to grease deterioration or insufficient oil film formation, suppresses temperature pulsation during grease replenishment, and reduces the number of single-row cylindrical rollers. It is possible to prevent deterioration of the shaft accuracy of the machine tool to which the bearing 130 is attached.
[0052]
A double-row cylindrical roller bearing 140 according to a fourteenth embodiment of the present invention shown in FIG. 14 includes an inner ring 141, an outer ring 142, a cylindrical roller 143 disposed between an inner ring track 141a of the inner ring 141 and an outer ring track 142a of the outer ring 142, and An outer ring guide retainer 144 is provided.
[0053]
The outer ring 142 has two flanges 142b formed at both ends in the axial direction and a flange 142d formed at the center of the inner diameter surface. Two outer raceways 142a are formed between the flanges 142b and 142d, respectively.
[0054]
The two cylindrical rollers 143 are arranged to be rollable along two outer raceways 142a and an inner raceway 141a formed on the outer peripheral surface of the inner race 141, respectively. Each of both ends of the outer raceway 142a is provided with a recess 142c at a position facing the edge 143a of the cylindrical roller 143, so that interference with the edge 143a is avoided.
[0055]
In the present embodiment, two supply holes 145 are provided as supply elements that penetrate the outer ring 142 in the radial direction and communicate with one of the escape portions 142c provided at both ends of each outer ring track 142a. The additional grease is supplied from the outside to the relief 142c inside the rolling bearing 140 in the radial direction via the supply hole 145.
[0056]
The bearing space of the cylindrical roller bearing 140 is initially filled with grease in an amount of 8 to 15% of the bearing space volume. When the bearing is used, the following grease replenishing method is applied. That is, the grease G is shot at appropriate timing (intermittently or periodically) through the supply holes 145 such that the supply amount per line is 0.004 cc to 0.1 cc. The replenished grease is adapted to the whole inside of the bearing with the rolling of the cylindrical roller 143, and makes up for the insufficient grease.
[0057]
In consideration of the grease shot variation, the upper limit of the replenishment amount at one time is 0.12 cc. Cylindrical roller bearings are more susceptible to temperature pulsations than angular ball bearings, so the amount of replenishment at one time must be smaller than the amount of replenishment to the angular ball bearing. Therefore, in the case of a cylindrical roller bearing, it is particularly preferable that the amount of grease supplied once per row is 0.005 cc to 0.02 cc. By performing grease shots within the above range, it is possible to prevent abnormal temperature rise due to grease deterioration or insufficient oil film formation and damage to bearings, suppress temperature pulsation during grease replenishment, and provide a double row cylindrical roller. It is possible to prevent deterioration of the shaft accuracy of the machine tool to which the bearing 140 is attached.
[0058]
A double-row cylindrical roller bearing 150 according to a fifteenth embodiment of the present invention shown in FIG. 15 includes an inner ring 151, an outer ring 152, a cylindrical roller 153 disposed between an inner ring track 151a of the inner ring 151 and an outer ring track 152a of the outer ring 152, and An outer ring guide retainer 154 is provided.
[0059]
The outer ring 152 has two flanges 152b formed at both ends in the axial direction and a flange 152d formed at the center of the inner diameter surface. Two outer raceways 152a are formed between the flanges 152b and 152d, respectively.
[0060]
The two cylindrical rollers 153 are arranged to be rollable along two outer raceways 152a and an inner raceway 151a formed on the outer peripheral surface of the inner race 151, respectively. Each of both ends of the outer raceway 152a is provided with a relief portion 152c, which is a concave portion, at a position facing the edge portion 153a of the cylindrical roller 153, so as to avoid interference with the edge portion 153a.
[0061]
In the present embodiment, four supply holes 155 are provided as supply elements that penetrate the outer ring 152 in the radial direction and communicate with the respective relief portions 152c provided at both ends of each outer ring track 152a. The additional grease is supplied from the outside to the relief portion 152c inside the rolling bearing 150 through the supply hole 155 in the radial direction.
[0062]
In the bearing space of the cylindrical roller bearing 150, grease is initially sealed in an amount of 8 to 15% of the bearing space volume. When the bearing is used, the following grease replenishing method is applied. That is, the grease G is shot at appropriate timing (intermittently or periodically) through the supply holes 155 such that the supply amount per line is 0.004 cc to 0.1 cc. The replenished grease is adapted to the whole inside of the bearing with the rolling of the cylindrical roller 153, and makes up for the insufficient grease.
[0063]
In consideration of the grease shot variation, the upper limit of the replenishment amount at one time is 0.12 cc. Cylindrical roller bearings are more susceptible to temperature pulsations than angular ball bearings, so the amount of replenishment at one time must be smaller than the amount of replenishment to the angular ball bearing. Therefore, in the case of a cylindrical roller bearing, it is particularly preferable that the amount of grease supplied once per row is 0.005 cc to 0.02 cc. By performing grease shots within the above range, it is possible to prevent abnormal temperature rise due to grease deterioration or insufficient oil film formation and damage to bearings, suppress temperature pulsation during grease replenishment, and provide a double row cylindrical roller. It is possible to prevent the shaft accuracy of the machine tool to which the bearing 150 is attached from deteriorating.
[0064]
Although some of the rolling bearings shown in FIGS. 1 to 15 have grooves provided on the outer diameter surface of the outer ring, and some do not, grooves may be provided or not provided for all rolling bearings.
Further, an O-ring may be provided on the outer diameter surface of the outer ring or the inner diameter surface of the housing to prevent grease leakage.
[0065]
FIG. 16 is a diagram showing a spindle device 160 as a machine tool spindle device configured using the rolling bearings described in the first to fifteenth embodiments according to the present invention. This spindle device 160 supports the main shaft 171 in the main shaft housing 161 by using the angular ball bearing 10 of the outer ring groove type of the first embodiment and the cylindrical roller bearing 100 of one side of the supply hole of the tenth embodiment. I have. Note that the spindle device of FIG. 16 uses different types of bearings for the purpose of illustration, but it may be configured with only the same type of bearings.
[0066]
The main spindle housing 161 has a housing main body 162, a front bearing housing 163 internally fitted and fixed to a front end (left side in the figure) of the housing main body 162, and a main body 161 after being internally fitted and fixed to a rear side (right side in the figure) of the housing main body 162. And a side housing 164. An outer ring pressing member 165 and an inner ring pressing member 166 are provided at an end of the front bearing housing 163, and a labyrinth is formed between the outer ring pressing member 165 and the inner ring pressing member 166. The rear end surface of the spindle housing 161 is covered by a cover 170.
[0067]
The main shaft 171 has two rolling bearings 10 and 10 (equivalent to those shown in FIG. 1) externally fitted to the front bearing housing 163 and one cylindrical roller bearing 100 (shown in FIG. 10) externally fitted to the rear bearing housing 164. (A single replenishing hole of the same type) is rotatably supported by the spindle housing 161. An outer race spacer 180 is arranged between the outer races 12 of the two rolling bearings 10, and an inner race spacer 176 is arranged between the inner races 11.
[0068]
A rotor 186 is externally fitted and fixed to a substantially central portion of the main shaft 171 in the axial direction. On the outer peripheral surface side of the rotor 186, a stator 187 is coaxially arranged at a predetermined distance. The stator 187 is fixed to the housing main body 162 via a stator fixing member 188 disposed on the outer peripheral surface side of the stator 187. A plurality of grooves 178 are formed between the housing main body 162 and the stator fixing member 188 in a direction along the circumferential direction of the main shaft 171. A coolant for cooling the stator 187 flows in the plurality of grooves 178.
[0069]
Similarly, between the housing main body 162 and the front bearing housing 163, a plurality of grooves 177 through which the housing and the coolant for bearing cooling flow are formed in a portion corresponding to the outer peripheral side of the angular ball bearing 10.
[0070]
Three grease supply ports 192 through which grease for supplying grease to each of the bearings 10, 10, 100 are supplied are opened in the rear end surface of the main shaft housing 161 along the circumferential direction (FIG. 16). Only one is shown). These three grease supply ports 192 communicate with grease supply passages 193a, 193b, and 193c formed in the housing main body 162, the front bearing housing 163, and the rear bearing housing 164, respectively (in FIG. 16, for convenience, Each grease supply path 193a, 193b, 193c is shown in the same cross section). Thus, the spindle device 160 of the present embodiment is configured to be able to supply grease into the spindle housing 161 from the grease supply device 190 provided outside via the grease supply pipe 191.
[0071]
The grease supply path 193a communicates with an opening 196 formed corresponding to the outer ring side of the single-row cylindrical roller bearing 100, and the grease supply path 193b is connected to the front side (left side in the drawing) of the angular ball bearing 10. The grease supply passage 193c communicates with an opening 194 formed corresponding to the outer ring side, and an opening 195 formed corresponding to the outer ring side of the angular ball bearing 10 disposed on the rear side (center in the figure). Is in communication with Thus, the grease supplied from the grease supply device 190 is independently supplied to the outer ring side of each of the bearings 10, 10, 100. The openings 194, 195, and 196 communicate with the supply holes 15, 15, and 105 shown in FIGS. 1 and 9, and grease is independently supplied to the inside of the bearing space via the supply holes 15, 15, and 105.
[0072]
The grease replenisher 190 is configured to be able to supply grease to each of the bearings 10, 10, 100 independently. That is, the grease replenishing device 190 performs grease shots at appropriate timings (intermittently or periodically) for each of the bearings 10, 10, 100 such that the amount of replenishment at one time is 0.004 cc to 0.1 cc. . The replenished grease adapts to the entire interior of the bearings 10 and 100 with the rolling of the balls 13 inside the bearing 10 and the rollers 103 inside the bearing 100, and makes up for the insufficient grease. Here, in the case of an angular ball bearing, the amount of grease replenished at one time is preferably 0.01 cc to 0.03 cc. In the case of a cylindrical roller bearing, the amount of grease replenished at one time is 0.005 cc. Preferably, it is ~ 0.02 cc. By performing a grease shot within the range described above, occurrence of abnormal temperature rise due to deterioration of grease or insufficient formation of an oil film and damage to the bearing are prevented, and temperature pulsation at the time of grease replenishment is suppressed. It is possible to prevent deterioration of the axis accuracy of the spindle device to which the 10, 100 is attached.
[0073]
In the present embodiment, the front housing 163 and the rear housing 164 have a grease discharge passage 197 communicating with the inside of the bearing space of each of the bearings 10, 10, 100. The grease is discharged from the grease discharge passage 197 to the outside of the apparatus through the outer peripheral opening 198 of the grease discharge passage 197.
[0074]
In the spindle device according to the present embodiment, the bearing 10 according to the first embodiment and the bearing 100 according to the tenth embodiment have been described as examples, but, of course, the bearing according to any of the other embodiments 2 to 9 or 11 to 15 or any of them. Combinations may be used instead.
Needless to say, the same effect can be expected even if the same supply hole is provided in the outer ring of the other bearing.
[0075]
FIG. 17 is a diagram showing a spindle device as a machine tool spindle device configured by using rolling bearings 200 and 210 according to the sixteenth and seventeenth embodiments described below. Note that the spindle device in FIG. 17 uses different types of bearings for the purpose of illustration, but may be configured with only the same type of bearings.
[0076]
The bearings 200 and 210 are fitted outside the main shaft 1 and inside the housing 7. The main shaft 1 is rotatable with respect to the housing 7 via bearings 200 and 210. Between the inner ring and the outer ring of the bearings 200 and 210, inner ring spacers 500a, 500b, 500c, 500d, 500e and outer ring spacers 600a, 600b, 600c, 600d, 600e are disposed along the main shaft 1 and the housing 7, respectively. Are arranged in order from the left in the drawing.
[0077]
At both ends in the axial direction of the inner ring spacers 500a and 500e and the outer ring spacers 600a and 600e, inner ring pressing members 8a and 8b and outer ring pressing members 9a and 9b are arranged, respectively, and a preload is applied to each bearing via each spacer. ing. A gap (not shown) is formed between the inner ring pressing member 8a and the outer ring pressing member 9a and between the inner ring pressing member 8b and the outer ring pressing member 9b, and a labyrinth is formed between the two pressing members.
[0078]
FIG. 18 is an enlarged sectional view of the spindle device shown in FIG. Here, the angular ball bearing 200 and its peripheral structure according to the sixteenth embodiment of the present invention will be described.
[0079]
Each of the angular ball bearings 200 shown in FIG. 18 includes an inner ring 201, an outer ring 202, a plurality of balls 203 arranged between an inner ring raceway 201a of the inner ring 201 and an outer ring raceway 202a of the outer ring 202, and a plurality of balls 203 arranged in a circumferential direction. A retainer 204 is provided for holding at intervals. The outer ring 202 has a tapered portion 202b on one side in the axial direction for holding the ball 203 with a contact angle. Hereinafter, one side in the axial direction where the tapered portion is formed is referred to as a front side, and the other side is referred to as a back side.
[0080]
In the present embodiment, a grease replenishing outer ring spacer 600b is arranged between the angular ball bearings 200. Two grease replenishing nozzles 4 penetrating the housing 7 are inserted into and fixed to the grease replenishing outer ring spacer 600b. Additional grease is supplied to the grease supply nozzle 4 from the external grease supply unit 2 via the supply pipe 3.
[0081]
The grease replenishing outer ring spacer 600b has a replenishing hole 205 as a replenishing element for replenishing additional grease into the inside of the angular ball bearing 200 from the tip of the nozzle 4. The supply hole 205 has a circular cross section with a diameter of 0.1 to 5 mm, and opens in the axial direction toward the inside of the bearing 200 (inner diameter side than the retainer 204). The supply hole 205 supplies additional grease between the inner ring 201 and the outer ring 202 in the axial direction from the rear side. The supplied grease is mainly supplied to the inner diameter side of the retainer 204.
[0082]
The supply holes 205 may be provided at a plurality of locations on the grease supply outer ring spacer 600b at intervals in the radial direction. It is preferable that the grease to be supplied is mainly supplied to the inner diameter side than the retainer 204, but may be supplied to the outer diameter side.
[0083]
The grease in an amount of 10 to 20% of the bearing space volume is initially sealed in the bearing space of each angular ball bearing 200. Then, after the use of the bearing is started, the grease supply device 2 sets the replenishment amount at one time to 0.004 cc to 0.1 cc via the supply hole 205 at an appropriate timing (intermittently or periodically). Grease shot. The replenished grease adapts to the entire inside of the angular ball bearing 200 as the ball 203 inside the angular ball bearing 200 rolls, and makes up for the insufficient grease. Here, it is preferable that the amount of grease supplied at one time is 0.01 cc to 0.03 cc. By performing the grease shot within the above range, it is possible to prevent the occurrence of abnormal temperature rise due to the deterioration of the grease or the insufficient formation of the oil film and the damage to the bearing, to suppress the temperature pulsation at the time of replenishing the grease, and to reduce the angular ball bearing 200 Can be prevented from deteriorating the axial accuracy of the spindle device to which the shaft is attached.
[0084]
FIG. 19 is an enlarged sectional view of the spindle device shown in FIG. 17. Here, a single-row cylindrical roller bearing 210 according to a seventeenth embodiment of the present invention will be described.
[0085]
The single row cylindrical roller bearing 210 holds the inner ring 211, the outer ring 212, the cylindrical roller 213 disposed between the inner ring track 211a of the inner ring 211 and the outer ring track 212a of the outer ring 212, and the rollers 213 at equal circumferential intervals. The holder 214 is provided.
[0086]
In the present embodiment, a grease replenishing outer ring spacer 600d is disposed adjacent to the cylindrical roller bearing 210 in the axial direction. The grease replenishing nozzle 4 that penetrates the housing 7 is inserted into and fixed to the grease replenishment outer ring spacer 600d. Additional grease is supplied to the grease supply nozzle 4 from the external grease supply unit 2 via the supply pipe 3.
[0087]
The grease replenishing outer ring spacer 600d has a replenishing hole 215 as a replenishing element for replenishing additional grease into the bearing 210 from the tip of the nozzle 4. The supply hole 215 has a circular cross section with a diameter of 0.1 to 5 mm, and is open in the axial direction toward the inside of the bearing 210 (inner side than the retainer 214). The supply hole 215 supplies additional grease between the inner ring 211 and the outer ring 212 in the axial direction from the rear side. The supplied grease is mainly supplied to the inner diameter side of the retainer 214.
The supply holes 215 may be provided at a plurality of locations on the grease supply outer ring spacer 600d at intervals in the radial direction. It is preferable that the supplied grease is mainly supplied to the inner diameter side than the retainer 214, but may be supplied to the outer diameter side.
[0088]
In the bearing space of each cylindrical roller bearing 210, grease is initially sealed in an amount of 10 to 20% of the bearing space volume. Then, after starting the use of the bearing, the grease supply device 2 sets the replenishment amount at one time to 0.004 cc to 0.1 cc via the supply hole 215 at an appropriate timing (intermittently or periodically). Grease shot. The replenished grease adapts to the entire inside of the cylindrical roller bearing 210 as the rollers 213 in the cylindrical roller bearing 210 roll, and makes up for the insufficient grease. Here, it is preferable that the amount of grease supplied at one time is 0.005 cc to 0.02 cc. By performing a grease shot within the range described above, the occurrence of abnormal temperature rise due to grease deterioration or insufficient oil film formation and damage to the bearing are prevented, and at the same time, temperature pulsation at the time of grease replenishment is suppressed. Can be prevented from deteriorating the axial accuracy of the spindle device to which the shaft is attached.
[0089]
FIG. 20 is an enlarged sectional view of a spindle device according to a first modification of the sixteenth embodiment.
The angular contact ball bearing 220 used in the present modified example rolls between the inner race 221 fitted on the shaft, the outer race 222 fitted on the housing 1000, and the inner raceway 221 a of the inner race 221 and the outer raceway 222 a of the outer race 222. It comprises a ball 223 that is freely arranged, and a holder 224 that holds the ball 223.
[0090]
The housing 1000 has a convex portion 1000a protruding radially inward. The outer ring 222 of the bearing 220 is in contact with the convex portion 1000a on the rear side in the axial direction. On the rear side in the axial direction of the inner ring 221, an inner ring spacer 510a axially facing the convex portion 1000a is disposed.
[0091]
On the other hand, a grease replenishing outer ring spacer 610 is provided on the axially front side of the outer ring 222. The grease replenishment outer ring spacer 610 is radially opposed to the inner ring spacer 510b. An opening 1000b for inserting the grease supply nozzle 400 into the grease supply outer ring spacer 610 is formed at a position corresponding to the outer diameter surface of the grease supply outer ring spacer 610 in the housing 1000. The base 400a of the grease supply nozzle 400 is fixed on the outer diameter surface of the housing 1000 by a fixing member 400b such as a screw, and the tip 400c extending from the base 400a is inserted into the grease supply outer ring spacer 610. Have been.
[0092]
The grease replenishing outer ring spacer 610 has a replenishing hole 225 as a replenishing element for replenishing additional grease into the inside of the bearing 220 from the tip part 400c of the grease replenishing nozzle 400. The supply hole 225 has a circular cross section having a diameter of 0.1 to 5 mm. The supply hole 225 supplies additional grease between the inner ring 221 and the outer ring 222 in the axial direction from the front side. It is preferable that the amount of the additional grease be 0.004 cc to 0.1 cc at one time supply and 0.01 cc to 0.03 cc at one time supply. By performing a grease shot within the range described above, it is possible to prevent the occurrence of abnormal temperature rise due to grease deterioration or insufficient oil film formation and damage to the bearing, suppress the temperature pulsation at the time of grease replenishment, and reduce the angular ball bearing 220 Can be prevented from deteriorating the axial accuracy of the spindle device to which the shaft is attached.
Note that the supply holes 225 may be provided at a plurality of locations on the outer ring spacer 610 for grease supply at intervals in the radial direction.
[0093]
FIG. 21 is an enlarged sectional view of a spindle device according to a second modification of the sixteenth embodiment.
The angular contact ball bearing 230 used in the present modification rolling between the inner race 231 fitted on the shaft, the outer race 232 fitted on the housing 1100, and the inner race 231a of the inner race 231 and the outer race 232a of the outer race 232. The ball 233 is freely arranged, and the holder 234 holds the ball 233.
[0094]
The housing 1100 has a convex portion 1100a protruding radially inward. The outer ring 232 of the bearing 230 is in contact with the projection 1100a on the front side in the axial direction. On the front side of the inner ring 231, an inner ring spacer 520b radially facing the convex portion 1100a is arranged. On the other hand, an inner ring spacer 520a and an outer ring spacer 620 are disposed on the rear side in the axial direction of the outer ring 232 so as to face each other.
[0095]
An opening 1100b for inserting the grease supply nozzle 400 into the projection 1100a is formed on the outer diameter surface of the housing 1000 opposite to the projection 1100a. The base 400a of the grease replenishing nozzle 400 is fixed on the outer diameter surface of the housing 1100 by a fixing member 400b such as a screw, and the tip 400c extending from the base 400a is inserted into the projection 1100a.
[0096]
The protrusion 1100a has a supply hole 235 as a supply element for supplying additional grease into the bearing 230 from the tip portion 400c of the grease supply nozzle 400. The supply hole 235 has a circular cross section with a diameter of 0.1 to 5 mm. The supply hole 235 supplies additional grease between the inner ring 231 and the outer ring 232 in the axial direction from the front side. It is preferable that the amount of the additional grease be 0.004 cc to 0.1 cc at one time supply and 0.01 cc to 0.03 cc at one time supply. By performing a grease shot within the range described above, it is possible to prevent the occurrence of abnormal temperature rise due to grease deterioration or insufficient oil film formation and damage to the bearing, to suppress temperature pulsation at the time of grease replenishment, and to improve the angular ball bearing 230. Can be prevented from deteriorating the axial accuracy of the spindle device to which the shaft is attached. Note that the supply holes 235 may be provided at a plurality of locations of the convex portion 1100a at intervals in the radial direction.
[0097]
FIG. 22 is an enlarged sectional view of a spindle device according to a third modification of the present embodiment.
In this modification, the front side and the back side of the angular ball bearing 230 of the second modification are interchanged, and the convex portion 1100a of the housing 1100 is provided on the axial back side of the angular ball bearing 230. Other configurations are the same as those shown in FIG.
[0098]
In this modification, additional grease is supplied axially from the back side between the inner ring 231 and the outer ring 232 from a supply hole 235 formed in the convex portion 1100a. It is preferable that the amount of additional grease be 0.004 cc to 0.1 cc at one time supply, and 0.01 cc to 0.03 cc at one time supply of grease. By performing a grease shot within the range described above, this prevents abnormal temperature rise due to grease deterioration or insufficient oil film formation and damage to the bearing, suppresses temperature pulsation during grease replenishment, and prevents angular It is possible to prevent the shaft accuracy of the spindle device to which the ball bearing 230 is attached from being deteriorated.
[0099]
FIG. 23 is an enlarged cross-sectional view of a spindle device according to a fourth modification of the sixteenth embodiment.
The angular contact ball bearing 240 used in this modification is rolling between the inner race 241 fitted on the shaft, the outer race 242 fitted on the housing 1200, and the inner raceway 241 a of the inner race 241 and the outer raceway 242 a of the outer race 242. The ball 243 is freely arranged, and the holder 244 holds the ball 243. At the front end of the outer race 1200, a convex portion 242b protruding radially inward from the tapered portion is formed.
[0100]
The outer ring 242 of the bearing 240 is in contact with the outer ring spacer 630a on the front side in the axial direction, that is, the protrusion 242b is in contact with the outer ring spacer 630b, and on the rear side in the axial direction. On the rear side and the front side of the inner ring 241, inner ring spacers 530a and 530b radially opposed to the outer ring spacers 630a and 630b are arranged.
[0101]
The housing 1200 has an opening 1200b on the outer diameter surface opposite to the convex portion 242b of the outer ring 242 for inserting the grease supply nozzle 400 into the convex portion 242b. The base 400a of the grease supply nozzle 400 is fixed on the outer diameter surface of the housing 1200 by a fixing member 400b such as a screw. It is inserted inside the part 242b.
[0102]
The convex portion 242b has a supply hole 245 as a supply element for supplying additional grease into the bearing 240 from the tip portion 400c of the grease supply nozzle 400. The supply hole 245 has a circular cross section with a diameter of 0.1 to 5 mm. The supply hole 245 supplies additional grease between the inner ring 241 and the outer ring 242 in the axial direction from the front side. It is preferable that the amount of additional grease be 0.004 cc to 0.1 cc at one time supply, and 0.01 cc to 0.03 cc at one time supply of grease. By performing grease shots within the range described above, this prevents abnormal temperature rise due to grease deterioration or insufficient oil film formation and damage to bearings, suppresses temperature pulsation during grease replenishment, and prevents angular It is possible to prevent the shaft accuracy of the spindle device to which the ball bearing 240 is attached from being deteriorated.
Note that the supply holes 245 may be provided at a plurality of locations of the convex portion 242b at intervals in the radial direction.
[0103]
FIG. 24 is an enlarged sectional view of a spindle device according to a fifth modification of the present embodiment.
This modification is a modification of the outer ring 242 of the angular ball bearing 240 of the fourth modification, in which the convex portion 242b of the outer ring 242 is formed on the axial rear surface side of the angular ball bearing 240. Other configurations are the same as those shown in FIG.
[0104]
In this modification, additional grease is supplied axially from the back side between the inner ring 241 and the outer ring 242 from a supply hole 245 formed in the convex portion 242b. It is preferable that the amount of additional grease be 0.004 cc to 0.1 cc at one time supply, and 0.01 cc to 0.03 cc at one time supply of grease. By performing grease shots within the range described above, this prevents abnormal temperature rise due to grease deterioration or insufficient oil film formation and damage to bearings, suppresses temperature pulsation during grease replenishment, and prevents angular It is possible to prevent the shaft accuracy of the spindle device to which the ball bearing 240 is attached from being deteriorated.
[0105]
By configuring as in the above-described sixteenth and seventeenth embodiments and the first to fifth modifications of the sixteenth embodiment, it is possible to replenish additional grease inside the bearing in the axial direction.
It is needless to say that the same effect can be expected even if the same supply holes are provided in other bearings.
The grease shot may be performed either when the spindle is stopped or when the spindle is rotating.
[0106]
【Example】
(Example 1)
The following experiment was conducted on the amount of grease supplied to the rolling bearing.
[0107]
A durability test was performed using a single-row cylindrical roller bearing (manufactured by NSK, nominal number N1014) having an inner ring inner diameter of 70 mm, an outer ring outer diameter of 110 mm, and a width of 20 mm. The grease used in the durability test was Isoflex NBU15 (manufactured by NOK Kluber Co., Ltd.), and the initial amount of grease was 10% of the bearing space volume. The test conditions were dmN = 1.5 million.
[0108]
In this endurance test, three bearings were prepared, and after starting the endurance test, grease was supplied to each bearing at 0.01 cc, 0.004 cc, and 0.002 cc every 6 hours. As a result, the bearing was seized early at 0.002 cc, but with 0.004 cc and 0.01 cc of grease supplied, no abnormality or failure occurred even after 1000 hours from the start of the durability test. . From the above results, it was found that there was no problem in the durability of the rolling bearing by setting the amount of grease supplied at one time to 0.004 cc or more.
[0109]
(Example 2)
A temperature pulsation confirmation test to confirm the relationship between the amount of grease replenishment and the temperature pulsation using angular ball bearings 740 and 750 with an inner ring inner diameter of 65 mm, an outer ring outer diameter of 100 mm, a width of 18 mm, a ball diameter of 7.144 mm, and a contact angle of 18 °. went. The grease used in the temperature pulsation confirmation test was Isoflex NBU15 (manufactured by NOK Cluever Co.), and the initial amount of grease was 15% of the bearing space volume. The test condition was dmN = 1.8 million.
[0110]
This pulsation confirmation test was performed using a test spindle device 700 shown in FIG. The test spindle device 700 has a configuration in which a housing main body 703 is supported by a housing block 702 arranged on a support base 701. Angular ball bearings 740 and 750 are fitted inside the outer housing 703 in a rear arrangement. The angular ball bearing main shaft 740 is fitted around the main shaft 710, and rotatably supports the main shaft 710.
[0111]
Between the angular ball bearings 740 and 750, an inner ring spacer 711 is provided between inner rings of the angular ball bearings 740 and 750, and an outer ring spacer 712 is provided between outer rings of the angular ball bearings 740 and 750, respectively. A rear end outer ring retainer 713 is provided on the rear end side (the right side in the figure) of the angular ball bearing 750 in the axial direction.
An outer ring pressing member 714 and an inner ring pressing member 715 are provided on the axial front end side (left side in the figure) of the angular ball bearing 740. Each of the angular ball bearings 740 and 750 is pressed by the outer ring pressing member 714 and the inner ring pressing member 715 in the axial direction toward the rear end outer ring pressing 713 side.
[0112]
Nozzle members 730, 730 are attached to the housing 703 so as to correspond to the respective angular ball bearings 740, 750. The nozzle members 730, 730 supply grease into the bearing space from the hole side provided on the outer ring of each of the angular ball bearings 740, 750. In the present temperature pulsation confirmation test, grease was supplied every hour after the start of the test. The experiment was conducted five times with the amount of grease supplied to each bearing at one grease replenishment being 0.035 cc, 0.10 cc, 0.15 cc, 0.30 cc, and 0.60 cc. FIGS. 26A and 26B are graphs showing the results of the temperature pulsation confirmation test. FIG. 26A shows a case where the grease supply amount is 0.035 cc, FIG. 26B shows a case where the grease supply amount is 0.10 cc, and FIG. (D) shows the case where the grease supply amount is 0.30 cc, and (e) shows the case where the grease supply amount is 0.60 cc.
[0113]
As shown in FIGS. 26A and 26B, when the grease supply amounts are 0.035 cc and 0.10 cc, the bearing temperature of the angular ball bearings 740 and 750 does not change at all even if the grease is supplied. Absent. However, as shown in FIG. 26 (c), when the grease replenishment amount is 0.15 cc, it can be seen that the temperature of the angular ball bearings 740, 750 increases by about 1 ° C. every time grease is replenished. Similarly, as shown in FIGS. 26 (d) and (e), even when the grease replenishment amounts are 0.30 cc and 0.60 cc, the temperature of the angular ball bearings 740 and 750 is reduced by 1 to 2 every time grease is replenished. It can be seen that the temperature has increased by about ゜ C.
[0114]
Here, the angular ball bearing 740 and the bearing 750 have different temperatures in a steady state before grease replenishment. The temperature difference in the steady state is caused by a difference in the peripheral structure between the angular ball bearing 740 and the angular ball bearing 750, for example, a difference in distance from the housing block 702, a positional relationship with a cooling device (not shown), and the like. It is considered that the temperature in the steady state is different because the heat suppression rate is different.
[0115]
In any case, in both the angular ball bearing 740 and the angular ball bearing 750, when the grease supply amount is 0.15 cc or more, as shown in FIGS. It is considered that the bearing generates heat due to the stirring resistance and the like, and the temperature of the bearing rises, that is, temperature pulsation occurs. Therefore, it has been found that by setting the amount of grease replenishment at one time to 0.1 cc or less, stable grease supply without temperature pulsation can be performed.
[0116]
【The invention's effect】
As described above, according to the present invention, a new grease is replenished before the grease is deteriorated early and the bearing is damaged, so that the grease is lubricated, but the high-speed rolling characteristics and the long-life rolling bearing are provided. Can be provided. In addition, by supplying grease to the rolling bearing so that the amount of replenishment at a time is 0.004 cc to 0.1 cc, a rolling bearing that does not generate temperature pulsation when grease is supplied, and a machine tool spindle using the same. It becomes possible to provide a device and a high-speed motor. In this way, by performing grease replenishment within the range described above, it is possible to prevent the occurrence of abnormal temperature rise due to grease deterioration or insufficient oil film formation and damage to the bearing, and to suppress temperature pulsation during grease replenishment, Deterioration of shaft accuracy of the machine tool to which the bearing is attached can be prevented.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a first embodiment according to the present invention.
FIG. 2 is a sectional view showing a second embodiment according to the present invention.
FIG. 3 is a sectional view showing a third embodiment according to the present invention.
FIG. 4 is a sectional view showing a fourth embodiment according to the present invention.
FIG. 5 is a sectional view showing a fifth embodiment according to the present invention.
FIG. 6 is a sectional view showing a sixth embodiment according to the present invention.
FIG. 7 is a sectional view showing a seventh embodiment according to the present invention.
FIG. 8 is a sectional view showing an eighth embodiment according to the present invention.
FIG. 9 is a sectional view showing a ninth embodiment according to the present invention.
FIG. 10 is a sectional view showing a tenth embodiment according to the present invention.
FIG. 11 is a sectional view showing an eleventh embodiment according to the present invention.
FIG. 12 is a sectional view showing a twelfth embodiment according to the present invention.
FIG. 13 is a sectional view showing a thirteenth embodiment according to the present invention.
FIG. 14 is a sectional view showing a fourteenth embodiment according to the present invention.
FIG. 15 is a sectional view showing a fifteenth embodiment according to the present invention.
FIG. 16 is a sectional view showing a spindle device formed by using the rolling bearing according to the first to fifteenth embodiments according to the present invention.
FIG. 17 is a cross-sectional view showing a spindle device formed by using the rolling bearing according to the sixteenth to seventeenth embodiments according to the present invention.
18 is an enlarged sectional view of the spindle device shown in FIG. 17, showing a sixteenth embodiment of the present invention.
19 is an enlarged sectional view of the spindle device shown in FIG. 17, showing a seventeenth embodiment of the present invention.
FIG. 20 is a sectional view showing a first modification of the sixteenth embodiment according to the present invention.
FIG. 21 is a sectional view showing a second modification of the sixteenth embodiment according to the present invention.
FIG. 22 is a sectional view showing a third modification of the sixteenth embodiment according to the present invention.
FIG. 23 is a sectional view showing a fourth modification of the sixteenth embodiment according to the present invention.
FIG. 24 is a sectional view showing a fifth modification of the sixteenth embodiment according to the present invention.
FIG. 25 is a view showing a test spindle device used in a temperature pulsation test of Example 2.
26A and 26B are graphs showing the results of a pulsation confirmation test of Example 2, wherein FIG. 26A shows a case where the grease supply amount is 0.035 cc, FIG. 26B shows a case where the grease supply amount is 0.10 cc, and FIG. Shows the case where the grease supply amount is 0.15 cc, (d) shows the case where the grease supply amount is 0.30 cc, and (e) shows the case where the grease supply amount is 0.60 cc.
[Explanation of symbols]
10, 20, 30, 40, 50 angular contact ball bearings (rolling bearings)
11, 21, 31, 41, 51 Inner ring
12, 22, 32, 42, 52 Outer ring
13,23,33,43,53 Ball (rolling element)
14,24,34,44,54 Cage
15, 25, 35, 45, 55 Supply hole
60, 70, 80, 90, 100, 110 Cylindrical roller bearings (rolling bearings)
61, 71, 81, 91, 101, 111 Inner ring
62, 72, 82, 92, 102, 112 Outer ring
63, 73, 83, 93, 103, 113 Cylindrical rollers (rolling elements)
64, 74, 84, 94, 104, 114 cage
65, 75, 85, 95, 105, 115 Supply holes

Claims (22)

A grease-lubricated rolling bearing, wherein a supply hole is provided in an outer ring, and grease is supplied through the supply hole such that a single supply amount is 0.004 cc to 0.1 cc. And rolling bearing. The rolling bearing according to claim 1, wherein the rolling element is a cylindrical roller. 2. The rolling bearing according to claim 1, wherein the replenishing hole has a contact angle, the rolling element is a ball, and the supply hole is opened at a position on the inner diameter surface of the outer ring that is shifted from a contact portion of the outer ring raceway. 3. The rolling bearing according to any one of claims 1 to 3, which is used to support a main shaft of a machine tool and a high-speed motor. The rolling bearing according to claim 1, wherein a diameter of the supply hole is in a range of 0.1 to 5 mm. The rolling bearing according to any one of claims 1 to 5, which is used in an environment where dmN is 1,000,000 or more. A grease-lubricated rolling bearing,
An outer ring having an outer raceway on the inner peripheral surface, an inner race having an inner raceway on the outer peripheral surface, and a rolling element rotatably provided between the outer raceway and the inner raceway,
A rolling bearing having a grease replenishing element for replenishing additional grease into the rolling bearing, wherein the replenishment amount of the additional grease at a time is 0.004 cc to 0.1 cc. The rolling bearing according to claim 7, wherein the grease replenishing element is a replenishing hole provided in the outer race. The rolling bearing according to claim 8, wherein the supply hole is provided in a radial direction. The rolling bearing according to claim 8, wherein the supply hole is provided in an axial direction. Furthermore, it has an outer ring spacer,
The rolling bearing according to claim 7, wherein the grease supply element is a supply hole provided in the outer race spacer. The rolling bearing according to any one of claims 7 to 11, wherein the rolling element is a cylindrical roller. The rolling according to any one of claims 7 to 11, having a contact angle, wherein the rolling element is a ball, and wherein the supply hole is opened at a position shifted from a contact portion of an outer raceway on an inner diameter surface of the outer race. bearing. The rolling bearing according to any one of claims 7 to 13, which is used to support a main shaft and a high-speed motor of a machine tool. The rolling bearing according to claim 7, wherein a diameter of the supply hole is in a range of 0.1 to 5 mm. The rolling bearing according to any one of claims 7 to 15, which is used in an environment where dmN is 1,000,000 or more. A machine tool spindle device in which a rolling bearing supporting the spindle is mounted in a housing,
The rolling bearing is grease-lubricated,
The rolling bearing has an outer ring having an outer raceway on an inner peripheral surface, an inner racer having an inner raceway on an outer peripheral surface, and a rolling element rotatably provided between the outer raceway and the inner raceway. ,
A grease replenishing element for replenishing additional grease in the rolling bearing,
The spindle device for a machine tool, wherein the additional grease is replenished at a time in a supply amount of 0.004 cc to 0.1 cc. The spindle device for a machine tool according to claim 17, wherein the grease supply element is a supply hole provided in the outer ring. 19. The spindle device for a machine tool according to claim 18, wherein the supply hole of the outer ring is provided in a radial direction. 19. The spindle device for a machine tool according to claim 18, wherein the supply hole of the outer ring is provided in an axial direction. Furthermore, it has an outer ring spacer,
The spindle device for a machine tool according to claim 17, wherein the grease supply element is a supply hole provided in an outer race spacer. The spindle device for a machine tool according to claim 17, wherein the grease supply element is a supply hole provided in a housing.

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