Rolling bearing device

Abstract

In a rolling bearing device, the goal is to supply lubricating oil efficiently and without waste, in accordance with the lubrication state of the rolling bearings, while maintaining their condition. [Solution] The rolling bearing device comprises an angular contact ball bearing 10 filled with a grease composition 15 and a lubricating oil supply mechanism 20. The lubricating oil supply mechanism 20 uses a detection unit 26 to detect the temperature, vibration, rotational torque of the bearing 10, the color, light transmittance / reflectance, odor, specific gravity, acid value, iron content, and moisture content of the grease composition 15. The control unit 22 determines the amount and timing of oil supply according to the output of the detection unit, drives the pump 24, and supplies lubricating oil from the tank 25 to the bearing 10. This method is less wasteful and more efficient compared to supplying lubricating oil to the angular contact ball bearing 10 periodically regardless of the lubrication state. Since there is no need to store excess lubricating oil, the tank 25 and, consequently, the rolling bearing device can be miniaturized.

Description

Technical Field

[0001] The present invention relates to a rolling bearing device including a rolling bearing and a lubricating oil supply mechanism, and a machine device such as a spindle device for a machine tool in which the rolling bearing device is incorporated.

Background Art

[0002] The main shaft of a machine tool is preferably rotated at high speed in order to increase machining efficiency, and various lubrication techniques are applied to the bearing. As lubrication methods suitable for a high-speed rotating main shaft, for example, methods such as air-oil lubrication and oil mist lubrication are known.

[0003] In recent years, in the field of machine tools, the need to address carbon neutrality and further cost reduction has been increasing, and accordingly, the need for grease lubrication has been growing. Grease lubrication is environmentally friendly because it does not require an air-oil supply device as auxiliary equipment required for air-oil lubrication or a structure for injecting air-oil into the bearing, and can suppress initial costs and operating costs.

[0004] On the other hand, since grease lubrication lubricates only with the initial grease composition enclosed at the time of bearing assembly, in high-speed rotation applications, deterioration is accelerated due to heat generation of the bearing, and it is difficult to ensure lubrication durability. Therefore, in grease lubrication, further measures to cope with higher speeds (improvement of lubrication durability) are required.

[0005] Regarding this, Patent Document 1 discloses a rolling bearing device including a rolling bearing and a lubricating oil supply mechanism connected to the bearing. The lubricating oil supply mechanism has a holding portion that holds lubricating oil and a supply portion that supplies the lubricating oil from the holding portion to a bearing space between the outer ring and the inner ring of the rolling bearing. According to such a configuration, it is possible to replenish lubricating oil even in grease lubrication.

Prior Art Documents

Patent Documents

[0006] [Patent Document 1] Patent No. 6495700 [Overview of the project] [Problems that the invention aims to solve]

[0007] However, Patent Document 1 does not contain any specific description of how much lubricating oil is supplied from the lubricating oil supply mechanism to the rolling bearings or at what timing. In this regard, the usual approach is to lubricate the rolling bearings at regular intervals as part of time-based maintenance (TBM), regardless of their lubrication status. In that case, lubricating oil may be supplied at times when it is not needed, which is not efficient. It is necessary to enlarge the tank in the holding section to account for the excess amount, and to further improve the reliability of each component.

[0008] As a result, the lubrication oil supply mechanism becomes larger, which degrades the performance of machine tools, particularly those used at high speeds, such as spindle devices for machine tools, where compactness is generally required in terms of machining rigidity, runout accuracy, and dynamic balance.

[0009] This invention has been made in view of these circumstances, and aims to provide a rolling bearing device in which a lubricating oil supply mechanism is attached to the rolling bearing, in order to ensure lubrication durability in grease lubrication even under high-speed rotation conditions, by supplying lubricating oil efficiently and without waste through condition-based maintenance (CBM) according to the lubrication state of the rolling bearing.

[0010] Furthermore, the present invention aims to miniaturize rolling bearing devices, and also to miniaturize mechanical devices used in high-speed rotation, such as spindle devices for machine tools, that incorporate rolling bearing devices. [Means for solving the problem]

[0011] To solve the above-mentioned problems, the present invention provides a rolling bearing device comprising a rolling bearing and a lubricating oil supply mechanism, wherein the rolling bearing comprises an inner ring, an outer ring, a plurality of rolling elements interposed between the inner ring and the outer ring, and a grease composition sealed in the bearing space between the inner ring and the outer ring, the lubricating oil supply mechanism comprises a holding part for holding lubricating oil, a supply part for supplying the lubricating oil held in the holding part to the bearing space of the rolling bearing, a detection part for detecting a lubrication characteristic value (lubrication characteristic index) related to the lubrication state of the rolling bearing, and a control unit for controlling the operation of the supply unit, wherein the control unit is configured to determine the amount of oil supplied from the supply unit and the timing of oil supply according to the output of the detection unit.

[0012] With this configuration, lubricating oil can be supplied in the appropriate amount and at the appropriate time according to the lubrication state of the rolling bearing, thereby maintaining a good grease lubrication state, which leads to long-term stabilization of the rolling characteristics of the rolling bearing and an improvement in its lifespan. Furthermore, because lubricating oil can be efficiently supplied according to the lubrication state of the rolling bearing, there is less wasted lubricating oil compared to supplying lubricating oil at fixed intervals regardless of the lubrication state. This allows for a smaller lubricating oil supply mechanism, including the holding part, and contributes to the overall miniaturization of the rolling bearing device.

[0013] In the rolling bearing device according to the invention, the detection unit may be configured to detect at least one of the following as the lubrication characteristic value: the temperature, vibration, and rotational torque of the rolling bearing, as well as the color, light transmittance / reflectance, odor, specific gravity, acid value, iron content, and moisture content of the grease composition.

[0014] Furthermore, in the rolling bearing device according to the invention, the detection unit can detect a plurality of lubrication characteristic values ​​from among the lubrication characteristic values, and the control unit can drive the supply unit to supply lubricating oil to the bearing space when the change in two or more of these lubrication characteristic values ​​exceeds a predetermined set value. In this case, one of the plurality of lubrication characteristic values can adopt a configuration in which the change amount of the rotational torque of the rolling bearing is used.

[0015] Alternatively, in the rolling bearing device according to the invention, the detection unit detects a plurality of lubrication characteristic values among the lubrication characteristic values, and the control unit drives the supply unit to supply lubricating oil to the bearing space when two or more of the lubrication characteristic values themselves exceed a preset set value. A configuration can be adopted. In this case, one of the plurality of lubrication characteristic values can adopt a configuration in which the value of the rotational torque of the rolling bearing is used.

[0016] Furthermore, in the rolling bearing device according to the invention, the preset set value can adopt a configuration determined based on the relationship between a plurality of lubrication characteristic values measured when the rolling bearing and the grease composition are in a normal state.

[0017] Also, in the rolling bearing device according to the invention, an intermediate seat adjacent to the rolling bearing in the axial direction is further provided, and the lubricating oil supply mechanism can adopt a configuration mounted on the intermediate seat. In this case, the intermediate seat can adopt a configuration that is an outer ring intermediate seat adjacent to the outer ring of the rolling bearing in the axial direction.

[0018] In the rolling bearing device according to the invention, the rolling bearing can adopt a configuration that is an angular ball bearing.

[0019] In order to solve the above problems, the mechanical device according to the invention is configured to include a rotating shaft, a housing disposed on the outer periphery of the rotating shaft, and the rolling bearing device according to the invention that rotatably supports the rotating shaft with respect to the housing. In this case, the rotating shaft can be configured as a spindle device for a machine tool that is a main shaft of a machine tool to which a cutting tool can be attached.

[0020] Since the mechanical device according to the invention is configured in this way, as a result of the reduction in size of the rolling bearing device, the mechanical device can be reduced in size, and it can be made suitable for use particularly at high speeds, such as in a spindle device for a machine tool.

Advantages of the Invention

[0021] Since the present invention is configured as described above, lubricating oil can be efficiently supplied without waste by condition-based maintenance (CBM) from the lubricating oil supply mechanism according to the lubrication state of the rolling bearing so as to ensure lubrication durability in grease lubrication. Also, this makes it possible to reduce the size of mechanical devices such as rolling bearing devices and spindle devices for machine tools.

Brief Description of the Drawings

[0022] [Figure 1] Longitudinal sectional view of the rolling bearing device of the embodiment [Figure 2] Block diagram of the lubricating oil supply mechanism [Figure 3] Flowchart showing the control of the lubricating oil supply mechanism [Figure 4] Longitudinal sectional view of the spindle device for a machine tool of the embodiment

Modes for Carrying Out the Invention

[0023] Hereinafter, embodiments of the present invention will be described while referring to the drawings. The rolling bearing device of the embodiment shown in FIGS. 1 to 3 includes an angular ball bearing 10 as a rolling bearing and a lubricating oil supply mechanism 20 that supplies lubricating oil into the bearing space of the angular ball bearing 10, and is preferably used for a mechanical device used particularly under high-speed rotation conditions such as a spindle device for a machine tool. Here, the high-speed rotation conditions specifically refer to a dn value of 70×10 4 or more, preferably 110×10 4 or more. The upper limit of the dn value is not particularly limited, but for example, it is 200×10 4 or 180×10 4 or the like. The rolling bearing device of this embodiment exhibits excellent lubrication durability even under such high-speed rotation conditions, and can be used for a long period of time.

[0024] As shown in Figure 1, the angular contact ball bearing 10 comprises an inner ring 11 having a raceway surface 11a on its outer diameter surface, an outer ring 12 having a raceway surface 12a on its inner diameter surface, and balls 13 acting as rolling elements interposed between the opposing raceway surfaces 11a and 12a. The inner ring 11 and outer ring 12 are made of metal. The ball 13 is made of metal or ceramic.

[0025] As shown in Figure 1, the multiple balls 13 are held by the cage 14 at regular intervals in the circumferential direction of the angular contact ball bearing 10. Furthermore, the bearing space formed between the inner ring 11 and the outer ring 12 is filled with a grease composition 15, which is interposed between the raceway surfaces 11a and 12a and the balls 13, thereby lubricating the angular contact ball bearing 10. Note that the distribution of the grease composition 15 in Figure 1 is merely illustrative and not limited to this.

[0026] Here, as shown in Figure 1, the inner ring 11 and the outer ring 12 are in contact with the ball 13 at a predetermined angle θ, so that the angular contact ball bearing 10 can support not only radial loads but also axial loads. One side of the raceway surface 11a of the inner ring 11 is a shoulder portion 11b. Furthermore, the shown retainer 14 is a so-called outer ring guide type retainer, and the guide surface 14a provided at the axial end of its outer diameter surface contacts the inner diameter surface of the outer ring 12, thereby guiding it to the outer ring 12.

[0027] As shown in Figure 1, a sealing member 16 is provided at one axial end of the bearing space where the grease composition 15 is sealed. The sealing member 16 is adjacent to the shoulder portion 11b of the inner ring 11. It is also possible to omit the sealing member 16. The other axial end of the bearing space is not provided with a sealing member 16 and is open.

[0028] As shown in Figure 1, the lubrication oil supply mechanism 20 is positioned adjacent to the end of the angular contact ball bearing 10 in the axial direction that is not provided with the sealing member 16. In the illustration, the lubrication oil supply mechanism 20 is incorporated into a spacer 30 that abuts against the width surface of the angular contact ball bearing 10. Although not shown in the diagram, the other end of the spacer 30 is abutted against the width surface of another angular contact ball bearing, and this spacer 30 adjusts the clearance and preload. The spacer 30 is made of metal.

[0029] As shown in Figure 1, the spacer 30 consists of an inner ring spacer 31 that abuts against the width surface of the inner ring 11 of the angular contact ball bearing 10, and an outer ring spacer 32 that abuts against the width surface of the outer ring 12. An annular casing 33 is fixed to the inner diameter surface of the outer ring spacer 32. The casing 33 consists of a casing body 33a and a cover 33b. The casing body 33a is closed on the side facing the width surface of the angular contact ball bearing 10 and open on the opposite side. The cover 33b detachably closes the opening of the casing body 33a. The lubrication oil supply mechanism 20 is housed within a casing 33 fixed to the outer ring spacer 32. By integrating it into the outer ring spacer 32, space savings are achieved.

[0030] Figure 2 shows the lubrication oil supply mechanism 20 in a functional block diagram. As shown in the figure, the lubrication oil supply mechanism 20 includes a power supply unit 21, a control unit 22, a drive unit 23, a pump 24 as a supply unit for supplying lubrication oil, a tank 25 as a holding unit for holding lubrication oil, and a detection unit 26 for detecting the lubrication state of the angular contact ball bearing. Note that the arrangement of these elements of the lubrication oil supply mechanism 20 is not limited to Figure 2.

[0031] As shown in Figure 2, the power supply unit 21 is capable of supplying power to the control unit 22 and the drive unit 23. The control unit 22 is composed of a microcontroller or the like and is capable of transmitting commands to the drive unit 23 in response to the output of the detection unit 26. The drive unit 23 is a drive circuit that operates the pump 24.

[0032] As shown in Figure 2, the pump 24 is capable of drawing in lubricating oil from the tank 25 and discharging a predetermined amount of lubricating oil toward the angular contact ball bearing 10. The types of pumps 24 mentioned here are not limited, but examples include pneumatic and hydraulic piston pumps, hydraulic pumps such as gear pumps, and diaphragm pumps.

[0033] The detection unit 26 is capable of detecting and measuring lubrication characteristic values ​​(lubrication characteristic indices) that serve as indicators of the lubrication state of the angular contact ball bearing 10, such as the temperature, vibration, rotational torque of the angular contact ball bearing 10, the color of the grease composition 15, the light transmittance and reflectance, odor, specific gravity, acid value, iron content, and moisture content. The installation location of the detection unit 26 is not limited and can be appropriately installed in accordance with the lubrication characteristic values ​​to be detected and measured. Figure 1 illustrates its installation inside and around the angular contact ball bearing 10.

[0034] As shown in Figure 2, the control unit 22 issues a command to the drive unit 23, which in turn activates the pump 24, and as shown in Figure 1, lubricating oil is supplied to the bearing space of the angular contact ball bearing 10 via the nozzle 27 protruding from the casing 33. As shown in the figure, the tip of the nozzle 27 extends into the bearing space through the opening described above. For example, when the angular contact ball bearing 10 is rotating its inner ring, the nozzle 27 discharges lubricating oil onto the outer diameter surface of the inner ring 11, including the raceway surface 11a, more specifically, near the side of the raceway surface 11a opposite to the shoulder portion 11b. The discharged lubricating oil moves to the raceway surface 11a due to centrifugal force and mixes with the grease composition 15 that is pre-sealed in the bearing space, improving the lubrication state of the angular contact ball bearing 10. The above is merely an example; the discharged lubricant only needs to reach the raceway surface, and the discharge point is not limited to the outer diameter surface including the raceway surface 11a of the inner ring 11, but may also be near the surface of the cage 14 or near the raceway surface 12a of the outer ring 12, for example.

[0035] The timing and amount of lubricating oil supplied from the lubricating oil supply mechanism 20 to the angular contact ball bearing 10 are controlled by the control unit 22 according to the output of the detection unit 26, as shown in Figure 2. As described above, the lubrication state of the angular contact ball bearing 10 is determined by various lubrication characteristic values ​​detected and measured by the detection unit 26, namely the temperature, vibration, and rotational torque of the angular contact ball bearing 10, as well as the color, light transmittance and reflectance, odor, specific gravity, acid value, iron content, and moisture content of the grease composition 15. Based on this, the control unit 22 determines the amount of lubrication to be supplied and the timing of lubrication. The type of detection unit 26 is not limited here, but examples of various sensors and measuring instruments include temperature sensors, vibration sensors, rotation sensors, color sensors, optical sensors (light transmittance meters, light reflectance meters), odor sensors, specific gravity sensors, torque sensors, acid value meters, iron content meters, moisture content meters, etc.

[0036] Generally speaking, poor lubrication results in a larger amount of oil being added each time and shorter intervals between oil changes, while good lubrication results in a smaller amount of oil being added each time and longer intervals between oil changes. However, the amount of lubricating oil supplied each time is preferably a very small amount that does not cause a sudden effect on the torque fluctuations of the angular contact ball bearing 10, and can be exemplified as about 0.001 mL to 0.1 mL. By supplying lubricating oil in the appropriate time and amount according to the lubrication state of the angular contact ball bearing 10, the grease lubrication state can be maintained in good condition, thereby ensuring long-term stability of its rolling characteristics and improving its lifespan. Because lubricating oil can be supplied efficiently, there is no need to store excess lubricating oil compared to supplying it at regular intervals, allowing for a smaller tank 25 and a smaller lubricating oil supply mechanism 20. As a result, it does not require a large installation space and can be easily integrated into a spacer 30, etc.

[0037] The detection unit 26 will be described in detail below. The lubrication characteristic values ​​that serve as indicators of the lubrication state of the angular contact ball bearing 10 include the temperature, vibration, and torque of the bearing 10. As shown in Figure 2, the detection unit 26 includes a temperature sensor, a vibration sensor, and a rotation sensor. When excessive load (excessive surface pressure) is applied to the angular contact ball bearing 10, or when the lubrication condition deteriorates, the contact ellipse of the rolling surface becomes larger, or metal-to-metal contact increases, causing the bearing's temperature, vibration, and rotational torque to rise. Furthermore, deterioration of the lubrication state at the contact points between the cage 14 and the balls 13, raceway surfaces 11a and 12a can also cause the temperature, vibration, and rotational torque of the angular contact ball bearing 10 to rise. Therefore, the detection unit 26 detects and measures the temperature, vibration, and rotational torque values ​​and their changes in the angular contact ball bearing 10, and based on this, the control unit 22 determines the amount and timing of lubrication oil to be supplied. In this respect, basing the decision on the amount of change is preferable because it offers greater responsiveness. It is also possible to make a decision by combining values ​​and amounts of change.

[0038] Furthermore, the lubrication characteristic values ​​that serve as indicators of the lubrication state of the angular contact ball bearing 10 include the color, light transmittance / reflectance, odor, specific gravity, acid value, iron content, and moisture content of the grease composition 15. As shown in Figure 2, the detection unit 26 includes a color sensor, optical sensors (light transmittance meter, light reflectance meter), odor sensor, specific gravity sensor, etc. (acid value meter, iron content meter, moisture content meter). A lack of lubricating oil on the raceway surfaces 11a and 12a of the angular contact ball bearing 10 is induced by the consumption or deterioration of the base oil in the grease composition 15 initially sealed in the bearing 10. For example, the grease composition 15 may discolor, change in specific gravity due to oil separation, or increase in acid value due to heat generated by the rotation of the angular contact ball bearing 10, or heat transmitted from other heat sources around the bearing 10, such as the stator coil of a motor. Note that the change in hue will vary depending on the type of grease composition.

[0039] Furthermore, wear particles generated in the rolling portion of the angular contact ball bearing 10 and in the contact area between the balls 13 of the cage 14 and the raceway surfaces 11a and 12a mix with the grease composition 15, causing discoloration of the grease composition 15, changes in light transmittance and reflectance, odor, specific gravity, and an increase in acid value and iron content. Generally, the discoloration of the grease composition 15 manifests as a change to a brownish or blackish hue. Alternatively, if moisture penetrates from the periphery of the angular contact ball bearing 10 into the interior, the moisture will mix with the grease composition 15. As a result, the lubrication performance of the grease composition will decrease, and the lubrication state of the angular contact ball bearing 10 will deteriorate. Therefore, the detection unit 26 detects and measures the color, light transmittance / reflectance, odor, specific gravity, acid value, iron content, and moisture content of the grease composition 15, as well as the changes therein. Based on this, the control unit 22 determines the amount and timing of lubrication oil to be supplied. In this respect, basing the decision on the amount of change is preferable because it offers greater responsiveness. It is also possible to make a decision by combining values ​​and amounts of change.

[0040] As a means of capturing changes in various elements that serve as indicators of the lubrication state (temperature, vibration, and rotational torque of the angular contact ball bearing 10, and the color, light transmittance / reflectance, odor, specific gravity, acid value, iron content, and moisture content of the grease composition 15), for example, a set value (threshold) can be predetermined based on the relationship between multiple lubrication characteristic values ​​measured when the angular contact ball bearing 10 and the grease composition 15 are in a normal state. In this case, when the measurement value in the detection unit 26 exceeds the threshold, the control unit 22 sends a signal to the drive unit 23, which then supplies lubricating oil to the angular contact ball bearing 10. In this context, the measured values ​​and thresholds include not only the lubrication characteristic value itself, but also the amount of change in the lubrication characteristic value. By combining multiple indicators and determining an abnormality when the change in multiple lubrication characteristic values ​​exceeds a threshold, misjudgments are suppressed and reliability is increased.

[0041] The temperature, vibration, and rotational torque of the angular contact ball bearing 10 are preferred indicators in this case because they can be easily observed without disassembly during operation. Among these, rotational torque is more preferred as an indicator because it is directly related to the lubrication state. Furthermore, the color, light transmittance / reflectance, odor, specific gravity, acid value, iron content, and moisture content of the grease composition 15 can occur as precursors to changes in the lubrication state, and are therefore preferred as indicators selected in this case because they allow for early prediction of changes in the lubrication state. Therefore, it is preferable to use a combination of the rotational torque of the angular contact ball bearing 10 and one of the characteristics of the grease composition 15 as indicators.

[0042] Figure 3 is a flowchart showing an example of lubricant supply control performed by the control unit 22. The processes in this flowchart are to be executed at regular intervals. Referring to Figure 2, in step S1, the control unit 22 obtains lubrication characteristic values ​​from the detection unit 26. In this case, it is preferable to obtain them from multiple detection units 26.

[0043] Next, in step S2, it is determined whether the lubrication characteristic value is greater than a threshold value pre-stored in the memory of the control unit 22. While not particularly limited, thresholds may be determined through prior testing or simulation, and may be manipulated and adjusted as appropriate by multiplying them by coefficients, etc. A table showing the relationships between multiple indicators can also be stored in memory, and decisions can be made based on this table.

[0044] If the lubrication characteristic value exceeds a threshold, in step S3, the control unit 22 supplies lubricating oil to the angular contact ball bearing 10 by driving the pump 24 for a predetermined time. After the predetermined time has elapsed, the pump 24 stops, and the process moves to step S4, then back to step S1. On the other hand, if the lubrication characteristic value falls below the threshold, the process in step S3 is not executed, and the process moves to step S4, then back to step S1.

[0045] The rolling bearing device of this embodiment is used, for example, in the spindle device 1 for a machine tool of this embodiment, as shown in Figure 4. As shown in the figure, the spindle device 1 for a machine tool includes a spindle 2 as the axis of rotation, a housing 3 consisting of an inner cylinder 3a and an outer cylinder 3b, and an angular contact ball bearing 10 that rotatably holds the spindle 2 relative to the inner cylinder 3a of the housing 3. A motor 4 is connected to one end of the spindle 2, and a cutting tool such as an end mill is connected to the other end. The motor 4 has a rotor 4a fixed to the outer circumference of the spindle 2, and a stator 4b fixed to the outer cylinder 3b, which rotates the spindle 2. The rolling bearing device of this embodiment consists of the angular contact ball bearing 10 and a lubrication oil supply mechanism 20, and the angular contact ball bearing 10 is positioned by a spacer 30. The lubrication oil supply mechanism 20 is incorporated into the outer ring spacer 32 of the spacer 30 and supplies lubricating oil to the angular contact ball bearing 10.

[0046] The embodiments disclosed herein are illustrative in all respects and not restrictive. The scope of the invention is defined by the claims and includes all modifications in the sense and scope equivalent to the claims.

[0047] In the embodiment, an angular contact ball bearing 10 was exemplified as a rolling bearing, but the rolling bearing in the rolling bearing device of the present invention is not limited to this, and may be a deep groove ball bearing, cylindrical roller bearing, tapered roller bearing, self-aligning roller bearing, needle roller bearing, thrust cylindrical roller bearing, thrust tapered roller bearing, thrust needle roller bearing, thrust self-aligning roller bearing, etc. Furthermore, the structure of the angular contact ball bearing 10 is not limited to the embodiment. For example, the structure of the cage 14 can be different from that of the embodiment.

[0048] In this embodiment, the lubrication oil supply mechanism 20 is incorporated into the outer ring spacer 32 of the spacer 30. However, the installation configuration of the lubrication oil supply mechanism 20 is not limited to this. It can also be incorporated into the inner ring spacer 31, or parts of the lubrication oil supply mechanism 20, such as a pump as the supply unit and a tank as the holding unit, may be placed inside a rolling bearing such as an angular contact ball bearing 10. Furthermore, the structure of the spacer 30, the structure of the casing 33, and the manner in which the lubricating oil supply mechanism 20 is incorporated into the outer ring spacer 32 are not limited to this embodiment. Furthermore, in this embodiment, the bearings 10 are arranged in a back-to-back configuration with spacers 30 in between, but they may also be arranged in a front-to-back or parallel configuration, and the configuration is not limited.

[0049] The type of base oil in the grease composition sealed in the bearing space and the type of lubricant supplied from the lubricant supply mechanism are not particularly limited, but it is preferable that the lubricant supplied from the lubricant supply mechanism be the same as, or has a similar composition to, the base oil in the grease composition sealed in the bearing space, and that an oil with high affinity to the base oil or an oil with a kinematic viscosity close to that of the base oil is used.

[0050] In the embodiment, a machine tool spindle device 1 was used as an example of a mechanical device, but the type of mechanical device is not limited to this, and the rolling bearing device according to the invention can be applied to mechanical devices other than machine tool spindle devices. Furthermore, the structure of the machine tool spindle device 1 is not limited to this embodiment. [Explanation of Symbols]

[0051] 1. Spindle device for machine tools 2 main shaft 3 Housing 3a Inner cylinder 3b Outer cylinder 4 motors 4a Rotor 4b stata 10 Angular Contact Ball Bearings 11 Inner circle 11a Raceway surface 11b Shoulder 12 Outer ring 12a Raceway surface 13 balls 14 Cage 14a Guide surface 15 Grease Compositions 16. Sealing member 20 Lubricating oil supply mechanism 21 Power supply section 22 Control Unit 23 Drive unit 24 pumps 25 tanks 26 Detection unit 27 nozzles 30 seats 31 Inner Wheel Spacer 32 Outer wheel spacer 33 Casing 33a Casing body 33b Lid

Claims

1. Rolling bearings and Equipped with a lubricating oil supply mechanism, The aforementioned rolling bearing is Insider, Outer ring and, A plurality of rolling elements interposed between the inner ring and the outer ring, The grease composition is sealed in the bearing space between the inner ring and the outer ring, The aforementioned lubrication oil supply mechanism is A retaining part that holds the lubricating oil, A supply unit that supplies lubricating oil held in the holding unit to the bearing space of the rolling bearing, A detection unit for detecting lubrication characteristic values ​​related to the lubrication state of the rolling bearing, It includes a control unit that controls the operation of the supply unit, The control unit, A rolling bearing device configured to determine the amount of oil supplied from the supply unit and the timing of oil supply according to the output of the detection unit.

2. The detection unit, As the aforementioned lubrication characteristic value, The temperature, vibration, and rotational torque of the aforementioned rolling bearing, and, The rolling bearing device according to claim 1, which detects at least one of the following of the grease composition: color, light transmittance / reflectance, odor, specific gravity, acid value, iron content, and moisture content.

3. The detection unit, From the aforementioned lubrication characteristic values, multiple lubrication characteristic values ​​are detected, The control unit, The rolling bearing device according to claim 2, wherein when the amount of change of two or more of the lubrication characteristic values ​​exceeds a predetermined set value, the supply unit is driven to supply lubricating oil to the bearing space.

4. The detection unit, From the aforementioned lubrication characteristic values, multiple lubrication characteristic values ​​are detected, The control unit, The rolling bearing device according to claim 2, wherein when two or more of the lubrication characteristic values ​​exceed predetermined set values, the supply unit is driven to supply lubricating oil to the bearing space.

5. The predetermined setting values ​​are: A rolling bearing device according to claim 3 or claim 4, wherein the rolling bearing and the grease composition are determined based on the relationship between a plurality of lubrication characteristic values ​​measured under normal conditions.

6. The rolling bearing device according to claim 5, wherein one of the plurality of lubrication characteristic values ​​is the rotational torque of the rolling bearing.

7. The rolling bearing further comprises spacers adjacent to the axial direction of the aforementioned rolling bearing, The rolling bearing device according to claim 1 or claim 2, wherein the lubrication oil supply mechanism is mounted on the spacer.

8. The rolling bearing device according to claim 7, wherein the spacer is an outer ring spacer adjacent to the outer ring of the rolling bearing in the axial direction.

9. The rolling bearing device according to claim 1 or claim 2, wherein the rolling bearing is an angular contact ball bearing.

10. The axis of rotation and A housing arranged on the outer circumference of the aforementioned rotating shaft, A mechanical device comprising a rolling bearing device according to claim 1 or 2, which rotatably supports the rotating shaft with respect to the housing.

11. The spindle device for a machine tool according to claim 10, wherein the rotating shaft is the main spindle of a machine tool to which a cutting tool can be attached.

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