JP2020063824A - Lubricating device and rolling bearing device - Google Patents

Abstract

To enable a flying distance of droplets of lubricant to be maintained while preventing the lubricant from being splashed.SOLUTION: A lubricating device comprises a pump 43 which ejects lubricant as droplets. The pump 43 has: a pump body 52 provided with a discharge hole 50 which discharges the lubricant and a pressure chamber 51 which is connected to the discharge hole 50; and a piezoelectric element 53 which deforms the pressure chamber 51 when a voltage is applied thereto. The pump 43 can eject droplets of lubricant through the discharge hole 50 by pressurizing the lubricant in the pressure chamber 51 with the voltage applied to the piezoelectric element 53. Given kinetic viscosity of the lubricant is expressed by X (in the unit of mm^2/sec), the voltage (in the unit of volt) to be applied to the piezoelectric element 52 is in a range between an upper limit value defined by 0.079X+14.9 and a lower limit value defined by 0.22X+5.3.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an oil supply device and a rolling bearing device provided with an oil supply device that supplies lubricating oil to a bearing portion.

  In recent years, in various machine tools, high-speed spindles are required to improve machining efficiency and production efficiency. When the main shaft rotates at high speed, lubricity becomes a problem especially in the bearing portion that supports the main shaft. Therefore, a rolling bearing device has been proposed in which an oil supply device including a pump for supplying lubricating oil to the bearing part is provided adjacent to the bearing part in the axial direction (see Patent Document 1).

JP, 2018-87597, A

  The pump of the oil supply device disclosed in Patent Document 1 has a configuration in which a small amount of oil droplets are ejected toward a part of the bearing portion by the operation of a piezo element (piezoelectric element). Therefore, the amount of lubricating oil consumed can be reduced to, for example, 1/1000 or less as compared with the oil-air lubrication system.

  FIG. 9 is an explanatory diagram showing a state in which the pump 90 discharges the oil droplet 99. When the lubricating oil is ejected from the discharge hole 91 of the pump 90 as the oil droplet 99, a droplet of the lubricating oil 98 (also referred to as satellite oil) may be formed after the leading oil droplet 99. is there. The splash oil 98 is separated from the leading oil drop 99 and returns to the pump 90 side due to its viscosity. The splash oil 98 that has returned to the pump 90 side is not collected inside the pump 90, but adheres to the outer surface 94 of the pump body 93 where the discharge hole 91 is opened, as shown in FIG. 10. If the splashed oil 98 adheres to the outer surface 94, it may block the discharge hole 91. In this case, it may be a hindrance when the lubricant oil is discharged from the discharge hole 91 later, resulting in defective discharge of the lubricant oil.

  In the case of the pump 90 that ejects lubricating oil as oil droplets by driving the piezo element as described above, if the voltage applied to the piezo element is set high, the flight distance of the oil droplet is extended. Further, the inventor of the present invention has empirically found that when the voltage applied to the piezo element is high and the condition is set close to the rated voltage, the splash oil 98 is easily generated.

  That is, when the voltage applied to the piezo element is set high, the flight distance of the oil droplet can be secured, but splash oil is likely to be generated, and the splash oil easily blocks the discharge hole of the pump. If the voltage is set low in order to suppress the generation of splashed oil, the flight distance of the oil droplet may be shortened.

  Therefore, the present invention provides an oil supply device capable of maintaining the flight distance of oil droplets and suppressing the generation of splash oil, and a rolling bearing device including such an oil supply device. .

The present invention is an oil supply device including a pump that ejects lubricating oil as oil droplets, wherein the pump includes a pump body in which a discharge hole for discharging the lubricating oil and a pressure chamber connected to the discharge hole are formed. A piezo element that deforms the pressure chamber when a voltage is applied, the pump pressurizes the lubricating oil in the pressure chamber by applying a voltage to the piezo element, and discharges the piezo element. When the lubricating oil can be ejected as oil droplets from the hole and the kinematic viscosity of the lubricating oil is X (unit: mm ^ 2 / sec), the voltage applied to the piezoelectric element (unit: Is the range between the upper limit value defined below and the lower limit value defined below.
Upper limit value: 0.079X + 14.9
Lower limit value: 0.22X + 5.3

  According to the oil supply device, the pressure inside the pump (pressure chamber) increases due to the voltage applied to the piezo element, and the pump ejects the lubricating oil as oil droplets from the discharge hole. By setting the voltage applied to the piezo element in the range between the upper limit value and the lower limit value, it is possible to maintain the flight distance of the oil droplets, and it is possible to stably supply the lubricating oil. is there. In addition, it is possible to suppress the generation of splash oil that may block the discharge hole of the pump.

Further, the upper limit value may be a value defined below.
Upper limit value: 0.10X + 13.8
That is, the voltage applied to the piezo element (however, the unit is volt) is between the upper limit value defined by the equation “0.10X + 13.8” and the lower limit value defined by “0.22X + 5.3”. It becomes a range. In this case, the oil droplet does not curve and fly, and the oil droplet easily reaches a desired position.

The rolling bearing device of the present invention includes an inner ring, an outer ring, and a bearing portion having a plurality of rolling elements interposed between the inner ring and the outer ring, and the bearing portion provided adjacent to the bearing portion in the axial direction. And the oil supply device for supplying lubricating oil.
According to this rolling bearing device, the voltage applied to the piezo element of the pump of the oil supply device is set in the range between the upper limit value and the lower limit value. Therefore, the flight distance of the oil droplet can be maintained, and the lubricating oil can be stably supplied. In addition, it is possible to suppress the generation of splash oil that may block the discharge hole of the pump.

  According to the present invention, it is possible to maintain the flight distance of oil droplets and to suppress the generation of splash oil.

It is a sectional view showing an example of a rolling bearing device. It is the figure which looked at the oil supply device from the axial direction. It is sectional drawing for demonstrating the schematic structure of a pump. It is explanatory drawing which shows the range of the voltage applied to a piezo element. It is a graph which shows the relationship between the voltage applied to a piezo element, and the flight distance of the oil droplet from a pump. 6 is a graph showing the relationship between the flight distance and the flight speed of an oil droplet from the pump when the voltage applied to the piezo element is changed. It is an image figure of the flight locus of the oil drop discharged from the pump. It is explanatory drawing which shows the range of the voltage applied to a piezo element. It is explanatory drawing which shows the state which the pump discharged the oil droplet. It is explanatory drawing of the state where the lubricating oil blocked the discharge hole.

[Overall structure]
FIG. 1 is a sectional view showing an example of a rolling bearing device. Although not shown, the rolling bearing device 10 (hereinafter referred to as “bearing device 10”) shown in FIG. 1 rotatably supports a spindle (shaft) of a spindle device included in a machine tool. It is housed in a bearing housing. The bearing device 10 can be applied to other than machine tools.

  The bearing device 10 includes a bearing portion 20 and an oil supply device (oil supply unit) 40. The bearing portion 20 includes an inner ring 21, an outer ring 22, a plurality of balls (rolling elements) 23, and a retainer 24 that holds the plurality of balls 23, and constitutes a ball bearing (rolling bearing). . Further, the bearing device 10 includes a cylindrical inner ring spacer 17 and an outer ring spacer 18. The inner ring 21 and the inner ring spacer 17 rotate integrally with the main shaft.

  The direction along the center line C of the bearing portion 20 (inner ring 21) is referred to as the “axial direction” of the bearing portion 20, and here, the direction parallel to the center line C is also included in the “axial direction”. Further, in FIG. 1, the right side is one side in the axial direction of the bearing portion 20, which is referred to as “one side in the axial direction”, and the left side is the other side in the axial direction of the bearing portion 20, which is The other side in the axial direction ".

  The oil supply device 40 has an annular shape as a whole and is provided on the inner peripheral side of the outer ring spacer 18. The oil supply device 40 is located adjacent to the bearing portion 20 on one side in the axial direction. The oil supply device 40 has a pump 43 and the like for supplying oil to the bearing portion 20. The configuration and the like of the oil supply device 40 will be described later. In the form of FIG. 1, the body part 41 and the outer ring spacer 18 described later of the refueling device 40 are separate members, but they may be formed of the same member.

  The inner ring 21 is a cylindrical member that is fitted onto the main shaft, and a track (hereinafter, referred to as an inner ring track 25) is formed on the outer circumference thereof. Although not shown, the inner ring 21 and the inner ring spacer 17 are separate members, but they may be formed of the same member. The outer ring 22 is a cylindrical member attached to the inner peripheral surface of the bearing housing, and a raceway (hereinafter referred to as an outer ring raceway 26) is formed on the inner periphery thereof. Although the outer ring 22 and the outer ring spacer 18 are separate members, although not shown, they may be formed of the same member. The balls 23 are interposed between the inner ring 21 and the outer ring 22 and roll on the inner ring raceway 25 and the outer ring raceway 26 when the inner ring 21 rotates. The cage 24 has an annular shape, and a plurality of pockets 27 for accommodating the balls 23 are formed along the circumferential direction. The balls 23 and the cage 24 are provided in the annular space 11 formed between the inner ring 21 and the outer ring 22.

  FIG. 2 is a diagram of the refueling device 40 as viewed from the axial direction. The oil supply device 40 includes a pump 42, a tank 42, a control unit 44, and a power supply unit 45. In the present embodiment, the tank 42, the pump 43, the control unit 44, and the power supply unit 45 are provided in the annular main body 41 of the refueling device 40. The tank 42 stores lubricating oil (oil) and is connected to the pump 43 through a pipe (tube) 46 for supplying the lubricating oil to the pump 43. The power supply unit 45 supplies electric power for operating the pump 43. The control unit 44 controls the timing of operating the pump 43 and the like.

  The control unit 44 is composed of, for example, a programmable logic controller. The control unit 44 has a function of outputting a drive signal to the piezo element 53 included in the pump 43, which will be described later.

  The main body portion 41 is attached to the inner peripheral side of the outer ring spacer 18 and has a function as a frame for holding the pump 43 and the like. The main body 41 is an annular member, but has a hollow space formed therein, and a tank 42, a pump 43, a control unit 44, and a power supply unit 45 are provided in this hollow space. As a result, the oil supply device 40 including the main body portion 41, the tank 42, the pump 43, the control portion 44, and the power supply portion 45 is integrally configured.

[About pump 43]
FIG. 3 is a cross-sectional view for explaining the schematic configuration of the pump 43. The pump 43 has a pump body 52 and a piezo element (piezoelectric element) 53. A pressure chamber (internal space) 51 is formed in the pump body 52. The volume of the pressure chamber 51 is changed by the operation of the piezo element 53, and the lubricating oil of the pressure chamber 51 is ejected from the discharge hole 50. The discharge hole 50 is connected to the pressure chamber 51 and opens toward the inner ring raceway 25 as shown in FIG. 1. The discharge hole 50 is formed by a linear minute through hole formed in the wall portion 49 of the pump body 52. The center line of the discharge hole 50 and the center line of the pressure chamber 51 are located on the common horizontal line L1. As the piezo element 53 operates, the lubricating oil is discharged from the discharge hole 50 as an oil droplet at an initial velocity. That is, for example, the oil droplets fly from the ejection holes 50 of the pump 43 so that the ink is ejected from the ejection holes formed in the inkjet head used in the printing technique. In FIG. 1, the jet direction of the oil droplet is indicated by arrow J.

  The pump 43 used in this embodiment is a pulse injector (inkjet head) manufactured by Cluster Technology Co., Ltd. The drive system is a piezo drive, which is a drop-on-demand system, and the nozzle diameter (diameter of the ejection hole 50) is 25 micrometers.

  The type of lubricating oil is general hydraulic oil. The lubricating oil used in this embodiment is mobile velocity oil number 10. Note that this lubricating oil is an example, and other types may be adopted.

  The operation of the pump 43 will be further described (see FIG. 3). A drive signal is intermittently output from the control unit 44 to the piezo element 53. The drive signal includes a drive voltage that deforms the piezo element 53. A drive voltage is applied to the piezo element 53 for a short time. The drive voltage is supplied from the power supply unit 45. When a voltage (driving voltage) is applied to the piezo element 53, the piezo element 53 deforms. When the voltage application is released, the deformation is restored. In the present embodiment, when a voltage (driving voltage) is applied to the piezo element 53, the deformation thereof elastically deforms the elastic film 54 forming a part of the wall surface 51 a of the pressure chamber 51, and the volume of the pressure chamber 51 is reduced. Expanding. The release of the voltage application causes the elastic restoring force of the elastic film 54 to reduce the volume of the pressure chamber 51. As a result, the lubricating oil in the pressure chamber 51 is discharged from the discharge hole 50 to the outside. The expansion of the volume of the pressure chamber 51 causes the lubricating oil to be replenished from the tank 42 side into the pressure chamber 51.

  In this way, when the drive signal is output to the piezo element 53, the internal pressure of the pressure chamber 51 rises and the lubricating oil is discharged. In this pump 43, the pressure increase in the pressure chamber 51 increases as the voltage applied to the piezo element 53 increases, and as a result, the lubricating oil discharge speed increases. This increases the flight distance of the lubricating oil. However, as will be described later, there is a limit to the increase of the ejection speed (flying distance), and a peak of the ejection speed (flying distance) occurs at a certain voltage. When the drive signal is not output to the piezo element 53, the internal pressure of the pressure chamber 51 does not change (remains at a low pressure) and the lubricating oil is not discharged.

  As described above, the oil supply device 40 (see FIG. 3) includes the tank 42 that stores the lubricating oil, and the pump 43 that is connected to the tank 42 via the lubricating oil flow path (the pipe 46). The pump 43 has a pump body 52 and a piezo element 53. Inside the pump body 52, a discharge hole 50 that opens at a part of the outer surface 49a of the wall portion 49 and a pressure chamber 51 that is connected to the discharge hole 50 are formed. The piezo element 53 deforms a part of the wall surface 51 a forming the pressure chamber 51 when a voltage is applied. By applying a voltage to the piezo element 53, the lubricating oil in the pressure chamber 51 is pressurized, and the lubricating oil is ejected from the discharge hole 50 as an oil droplet.

  The pump 43 (see FIG. 1) is provided adjacent to one side of the bearing portion 20 in the axial direction and ejects the lubricating oil toward the inner ring 21 as oil droplets. From the viewpoint of efficient use of lubricating oil, the pump 43 ejects a predetermined amount of oil droplets in one discharge operation, and the oil droplets reach part of the bearing portion 20 (for example, the inner ring raceway surface 25). Let With one operation of the pump 43, several picoliters to several nanoliters of lubricating oil are ejected as oil droplets from the discharge hole 50. The pump 43 of this embodiment ejects about 5 picoliters or more and 0.8 nanoliters of lubricating oil as oil droplets.

[Regarding the drive voltage of the pump 43]
The drive voltage of the pump 43, that is, the voltage applied to the piezo element 53 will be described. In the oil supply device 40 of the present embodiment, the flight distance of the oil droplet 99 (see FIG. 9) discharged from the pump 43 can be maintained, and the generation of the splash oil 98 is suppressed. Therefore, the voltage applied to the piezo element 53 is set as follows.

When the kinematic viscosity of the lubricating oil is X (unit: mm ^ 2 / sec), the voltage (unit: volt) applied to the piezo element 53 is the upper limit value defined by Equation 1 below. And a lower limit value defined by the following equation 2 are set.
Upper limit: 0.079X + 14.9 (Equation 1)
Lower limit value: 0.22X + 5.3 (Equation 2)

  As described above, the pump 43 is a pulse injector (inkjet head), and the drive system is the drop-on-demand system by piezo drive. The nozzle diameter (diameter of the discharge hole 50) is 25 micrometers. The lubricating oil used is mobile velocity oil number 10.

  FIG. 4 is an explanatory diagram showing the range of the voltage applied to the piezo element 53. In FIG. 4, the voltage applied to the piezo element 53 is set according to the kinematic viscosity of the lubricating oil within the range indicated by the hatch between the upper limit value (Formula 1) and the lower limit value (Formula 2).

The upper limit value (Equation 1) is obtained as follows.
FIG. 5 is a graph showing the relationship between the voltage applied to the piezo element 53 and the flight distance of the oil droplet from the pump 43. This graph was obtained by testing. In the test, the oil droplet whose flight distance is to be measured is not the splash oil 98 shown in FIG. 9 but the leading oil droplet 99. The temperature of the pump 43 and the lubricating oil therein is constant at a predetermined temperature, and the kinematic viscosity (viscosity) of the lubricating oil is constant at a predetermined value. As shown in FIG. 5, when the kinematic viscosity of the lubricating oil is constant and the voltage applied to the piezo element 53 is changed, the flight distance increases as the voltage increases from 10 volts. However, when the voltage is 17 V, the change of the flight distance has a peak, and within the range of the operating voltage (rated voltage) of the pump 43, the flight distance does not extend any further. Such a test is performed by changing the kinematic viscosity of the lubricating oil variously, and the voltage indicating the peak flight distance of the oil droplet 99 at each kinematic viscosity is obtained. The plot shown by the rhombus in FIG. 4 is the voltage showing the peak of the flight distance at a given kinematic viscosity. The upper limit value (Equation 1) can be obtained from the relationship between the kinematic viscosity of the lubricating oil and the peak voltage. (Formula 1) is obtained, for example, by the method of least squares. The kinematic viscosity is changed by changing the temperatures of the pump 43 and the lubricating oil.

  The change in the flight distance of the oil droplet 99 shown in FIG. 9 has a peak as described above, but the droplet oil 98 has no peak and is more likely to occur as the voltage applied to the piezo element 53 is increased. The flight distance of the splash oil 98 is extended. Therefore, in order to suppress the splash oil 98, it is preferable to set the voltage applied to the piezo element 53 as low as possible.

The lower limit value (Formula 2) is obtained as follows.
FIG. 6 is a graph showing the relationship between the flight distance and the flight speed of the oil droplet 99 from the pump 43 when the voltage applied to the piezo element 53 is changed. This graph is obtained by changing the voltage applied to the piezo element 53 and calculating the velocity at each flight distance from the initial velocity of the oil droplet at each voltage. It is assumed that the oil droplets 99 ejected from the pump 43 are brought into contact with the balls 23 of the bearing portion 20 (see FIG. 1). Therefore, the distance from the surface of the pump 43 where the discharge hole 50 opens to the ball 23 is L millimeters (L is 7 millimeters in this embodiment). In order for the oil droplet 99 to reach the ball 23, the flight speed of the oil droplet 99 needs to be zero or more at the point where the flight distance is L millimeters. Therefore, in FIG. 6, the voltage when the flight speed of the oil droplet 99 becomes zero at the point where the flight distance is L millimeters is acquired. In this embodiment, L is 7 millimeters, and in the case of FIG. 6, the voltage (minimum voltage) when the flight speed of the oil droplet 99 is zero at the point of 7 millimeters is 13 volts. It should be noted that the temperature of the pump 43 and the lubricating oil inside the pump 43 is constant at a predetermined temperature, and the kinematic viscosity (viscosity) of the lubricating oil is constant at a predetermined value. Such a test is performed by changing the kinematic viscosity of the lubricating oil variously, and the voltage (minimum voltage) when the flight speed of the oil droplet 99 becomes zero at a point of L millimeter (7 millimeter) in each kinematic viscosity get. A plot shown by a circle in FIG. 4 is a voltage when the flight speed of the oil drop 99 becomes zero at a point of L millimeter (7 millimeter) at a predetermined kinematic viscosity. The lower limit value (Equation 2) is obtained from the relationship between the kinematic viscosity and the voltage. (Formula 2) is obtained, for example, by the method of least squares. The kinematic viscosity is changed by changing the temperatures of the pump 43 and the lubricating oil. The L millimeter can be changed, and the lower limit (Equation 2) is satisfied within a range of 5 millimeters ≦ L ≦ 10 millimeters.

  As described above, according to the oil supply apparatus of the present embodiment, the pressure inside the pump 43 (the pressure chamber 51) increases due to the voltage applied to the piezo element 53, and the pump 43 causes the lubricating oil to flow from the discharge hole 50. Are ejected as oil droplets. The voltage applied to the piezo element 53 is set in the range between the upper limit value (Equation 1) and the lower limit value (Equation 2). By setting the lower limit value, the flight distance of the oil drop 99 can be maintained, and the lubricating oil can be stably supplied. Moreover, by setting the upper limit value, it is possible to suppress the generation of splash oil 98 (see FIG. 9) that may block the discharge hole 50 of the pump 43.

Regarding the upper limit value, the following (Formula 3) may be adopted instead of the above (Formula 1).
Upper limit value: 0.10X + 13.8 (Equation 3)

The upper limit value (Formula 3) is obtained as follows.
FIG. 7 is an image diagram of the flight trajectory of the oil droplet 99 discharged from the pump 43. The temperature of the pump 43 and the lubricating oil inside the pump 43 is kept constant at a predetermined temperature, and the kinematic viscosity (viscosity) of the lubricating oil is kept constant at a predetermined value. The flight trajectory of the oil droplet 99 is acquired by changing the voltage applied to the piezo element 53. This flight trajectory is acquired by photographing the oil droplet 99 with a camera. As shown in FIG. 7, when the voltage applied to the piezo element 53 is changed to 16 volts, 17 volts, 18 volts, ... At a certain voltage (17 volts in this case) or more, the trajectory of the oil droplet 99 flies. Becomes a curved locus. It is presumed that this is because when the voltage is increased, the flow velocity of the lubricating oil increases in the discharge hole 50, which causes turbulence in the discharge hole 50.

  Therefore, the kinematic viscosity of the lubricating oil is changed, and at each kinematic viscosity, the voltage when the flight trajectory of the oil droplet 99 is curved is acquired. FIG. 8 is an explanatory diagram showing the range of the voltage applied to the piezo element 53. The plot shown by the square in FIG. 8 is the voltage when the flight distance of the oil drop 99 is curved at a predetermined kinematic viscosity. The upper limit value (Equation 3) is obtained from the relationship between the kinematic viscosity and the voltage. (Formula 3) is obtained by, for example, the least square method. The kinematic viscosity is changed by changing the temperatures of the pump 43 and the lubricating oil. In FIG. 8, (Formula 3) is shown by a solid line, and (Formula 1) is shown by a broken line.

  Thus, when the kinematic viscosity of the lubricating oil is X (however, the unit is mm ^ 2 / sec), the upper limit value of the voltage (however, the unit is volt) applied to the piezo element 53 is the same as the above (formula 3). ) May be defined. That is, the voltage (unit: volt) applied to the piezo element 53 depends on the upper limit value defined by “Equation 3” “0.10X + 13.8” and the above-mentioned “Equation 2” “0.22X + 5.3”. The range is between the defined lower limit value. In this case, the generation of the splash oil 98 is suppressed, the oil droplet 99 does not curve and fly, and the oil droplet 99 easily reaches the desired position.

  If the kinematic viscosities are the same even if the types of lubricating oil are different, the above-described upper limit value (Equation 1 and Expression 2) and the lower limit value (Equation 2) are satisfied. The type of lubricating oil is a general hydraulic oil, for example, mobile velocity oil number 10. The discharge hole 50 of the pump 43 has a diameter (diameter) of 15 μm or more and 40 μm or less, and is 25 μm in the present embodiment. The kinematic viscosity of the lubricating oil is based on JIS Z 8803: 2011.

[Other]
In the embodiment described above (see FIG. 1), the case where the bearing portion 20 is an angular ball bearing has been described, but the type of bearing is not limited to this, and may be a deep groove ball bearing, or a tapered roller bearing, It may be a cylindrical roller bearing. That is, the rolling bearing device 10 includes an inner ring 21, an outer ring 22, a bearing unit 20 having a plurality of rolling elements interposed between the inner ring 21 and the outer ring 22, and an oil supply device 40. The oil supply device 40 is provided next to the bearing portion 20 in the axial direction and has a function of supplying lubricating oil to the bearing portion 20. The refueling device 40 may be the refueling device of the above-mentioned form. According to the rolling bearing device 10, the voltage applied to the piezo element 53 of the pump 43 included in the oil supply device 40 is set in the range between the upper limit value and the lower limit value. Therefore, the flight distance of the oil droplet can be maintained, and the lubricating oil can be stably supplied. In addition, it is possible to suppress the generation of splash oil that may block the discharge hole 50 of the pump 43.

  The embodiments disclosed this time are illustrative in all points and not restrictive. The scope of rights of the present invention is not limited to the above-described embodiments, and includes all modifications within the scope equivalent to the configurations described in the claims.

10: Rolling bearing device 20: Bearing part 21: Inner ring 22: Outer ring 23: Ball (rolling element) 40: Oil supply device 43: Pump 50: Discharge hole 51: Pressure chamber 52: Pump body 53: Piezo element 99: Oil droplet

Claims (3)

An oil supply device including a pump for ejecting lubricating oil as oil droplets,
The pump has a pump body in which a discharge hole for discharging the lubricating oil and a pressure chamber connected to the discharge hole are formed, and a piezo element that deforms the pressure chamber by applying a voltage, The pump is capable of pressurizing the lubricating oil in the pressure chamber by applying a voltage to the piezo element and ejecting the lubricating oil as oil droplets from the discharge hole,
When the kinematic viscosity of the lubricating oil is X (where the unit is mm ^ 2 / sec), the voltage applied to the piezo element (however, the unit is volt) is the upper limit value defined below and the following: Refueling equipment, which is the range between the lower limit defined in.
Upper limit value: 0.079X + 14.9
Lower limit value: 0.22X + 5.3 The refueling device according to claim 1, wherein the upper limit value is a value defined below.
Upper limit value: 0.10X + 13.8 An inner ring, an outer ring, and a bearing portion having a plurality of rolling elements interposed between the inner ring and the outer ring,
An oil supply device which is provided adjacent to the bearing portion in the axial direction and supplies lubricating oil to the bearing portion,
A rolling bearing device, wherein the oil supply device is the oil supply device according to claim 1.

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