TWI733779B - Bearing device - Google Patents

Abstract

A bearing device includes a bearing portion (20) that includes an inner ring (21), an outer ring (22), a plurality of rolling elements (23) that are interposed between the inner ring (21) and the outer ring (22), and a cage (24) that holds the plurality of rolling elements (23), one of the inner ring (21) and the outer ring (22) being a rotational ring, and another of the inner ring (21) and the outer ring (22) being a fixed ring; and an oil supply unit (40) that is provided adjacent to the bearing portion (20) in an axial direction. The cage (24) includes a guide portion that is configured to be in sliding contact with a part of the fixed ring via lubricating oil. The oil supply unit (40) includes a vibration sensor (55) configured to detect a vibration of the fixed ring, and a pump (43) configured to supply the lubricating oil to the bearing portion (20).

Description

Bearing device

The present invention relates to a bearing device including a bearing part, and an oil supply unit arranged adjacent to the bearing part in the axial direction.

In recent years, various machine tools have been required to have a spindle that rotates at a higher speed in order to improve machining efficiency and productivity. When the spindle is rotating at a high speed, the lubricating properties are especially important in the bearing part supporting the spindle. Therefore, a bearing device including an oil supply unit is proposed, the oil supply unit is provided in a spacer ring that is set to adjoin a bearing portion in the axial direction (see Japanese Patent Application Publication No. 2014-219078 No. (JP 2014-219078 A)). The oil supply unit includes a storage tank for storing lubricating oil, and a pump for discharging the lubricating oil in the tank to the annular space between the inner ring and the outer ring.

In addition to the storage tank and the pump, the oil supply unit of the bearing device described in Japanese Patent Application Publication No. 2014-219078 (JP 2014-219078 A) further includes a temperature sensor and a control unit (microcomputer). The fuel supply unit is constructed so that the detection signal of the temperature sensor is input To the control unit, and the control unit controls the pump to adjust the amount of lubricating oil to be supplied to the bearing part.

When the lubricating oil is evacuated, for example, in the bearing part to cause a poor lubrication state, the temperature rises. Therefore, with the temperature sensor, the lubrication state in the bearing part can be detected by detecting the increase in temperature. Similarly, in the bearing device described in Japanese Patent Application Publication No. 2014-219078 (JP 2014-219078 A), the control unit controls the pump to supply lubricating oil, and therefore, the temperature rise can be suppressed.

However, in the case of the bearing device described in Japanese Patent Application Publication No. 2014-219078 (JP 2014-219078 A), the temperature sensor is included in the oil supply unit attached to the outer ring spacer In the control unit, and is constructed to measure the temperature on the spacer. Therefore, in some cases, the temperature sensor cannot accurately and quickly detect changes in the temperature of the bearing part. Accordingly, when the temperature has risen as a result of the shortage of oil in the bearing part, the detection of the temperature rise can be delayed. As a result, hot sticking, etc. can occur in the bearing part.

The present invention provides a bearing device which can prevent the occurrence of heat-generating seizure and the like due to the shortage of oil in the bearing part.

One aspect of the present invention relates to a bearing device. The bearing device includes a bearing part, which includes an inner ring, an outer ring, a plurality of rolling elements inserted between the inner ring and the outer ring, and a spacer ring holding the plurality of rolling elements, one of the inner ring and the outer ring is rotated Ring, and the other of the inner ring and the outer ring is a fixed ring; And the oil supply unit, which is set to adjoin the bearing part in the axial direction. The isolating ring includes a guide part that is configured to make sliding contact with a part of the fixed ring through lubricating oil, and the oil supply unit includes a vibration sensor configured to detect the vibration of the fixed ring, and is configured to use The lubricating oil is supplied to the pump of the bearing part.

The bearing device is constructed so that the guiding part of the isolating ring is in sliding contact with a part of the fixed ring via lubricating oil, and the isolating ring is therefore positioned by the fixed ring. Accordingly, the heat system is most likely to be generated in the sliding contact part between the guiding part of the isolation ring and a part of the fixed ring. When oil shortage (and indication of oil shortage) occurs due to, for example, the exhaustion of lubricating oil in the sliding contact part, the contact state between the guide part of the isolating ring and the part of the fixed ring changes, and this change appears to be fixed Vibration of the ring. Therefore, the vibration sensor of the fuel supply unit detects vibration. Therefore, the shortage of oil (and the indication of the shortage of oil) can be detected based on the vibration of the fixed ring, and it is possible to prevent the occurrence of thermal adhesion and the like due to the shortage of oil.

When the shortage of oil occurs in the part of the fixed ring, the inventor of the present invention has found that the peak vibration waveform (peak waveform) is generated in the fixed ring. Therefore, the bearing device may include a control unit, which is configured to compare the level of the detection signal of the vibration sensor and the threshold, and output a control signal for when the level is higher than the threshold, due to the comparison As a result, the pump supplies lubricating oil. With this structure, oil shortages (and indications of oil shortages) can be detected at an early stage. For example, in a case where the pump is constructed to supply lubricating oil to the bearing part in a given cycle, a signal for reducing a given cycle (that is, a signal for causing a shortage of a given cycle) can be used do The control signal (that is, the pump can be configured to supply lubricating oil to the bearing part in a given cycle, and the control signal can be a signal for reducing the given cycle). Alternatively, a signal for increasing the amount of lubricating oil discharged by the pump may be used as a control signal (that is, the control signal may be a signal for increasing the amount of lubricating oil discharged by the pump).

The oil supply unit may further include a temperature sensor configured to detect the temperature of a part of the bearing part that is different from the sliding contact part between the fixed ring part and the guide part. When the amount of lubricating oil decreases due to, for example, its exhaustion in the bearing part, the temperature inside the bearing rises. Therefore, the temperature sensor detects this increase in temperature, and according to this, the decrease in the amount of lubricating oil can be detected. Furthermore, the temperature sensor detects the temperature of the part different from the sliding contact part. Therefore, in conjunction with the vibration sensor, the temperature sensor can further enhance the reliability in detecting the lubrication state at the bearing portion.

The bearing device may further include a control unit configured to determine whether the first detection signal of the vibration sensor satisfies the predetermined first condition, and used to determine whether the second detection signal of the temperature sensor satisfies the predetermined first condition Two conditions and a control signal for outputting a control signal for making the pump supply lubricating oil when one of the set first condition and the set second condition is satisfied. Therefore, the reliability of detecting the lubrication state in the bearing part can be further enhanced. For example, in a case where the pump is constructed to supply lubricating oil to the bearing part in a given cycle, the signal to reduce the given cycle (that is, the signal used to cause a shortage of the given cycle) can be used as a control signal (That is, the pump can be constructed to supply lubricating oil to the bearing part in a given cycle, and control The signal can be a signal used to reduce a given cycle). Alternatively, a signal for increasing the amount of lubricating oil discharged by the pump may be used as a control signal (that is, the control signal may be a signal for increasing the amount of lubricating oil discharged by the pump). The predetermined first condition can be a condition that the level of the first detection signal is higher than the first threshold; and the predetermined second condition can be a level system based on the temperature change of the second detection signal over time Conditions above the second threshold.

The guide part of the spacer ring can be constructed to be in sliding contact with the part of the fixed ring on one side in the axial direction via lubricating oil; the oil supply unit can be arranged on one side of the bearing part in the axial direction, The oil supply unit is adjacent to the bearing part; and the vibration sensor can be set closer to the fixed ring than the rotating ring in the radial direction. With this configuration, the sensitivity of the fixed ring in the direction of vibration by the vibration sensor is enhanced.

The fixed ring may include a raceway and a shoulder. A plurality of rolling elements are in rolling contact with the raceway, and the shoulders are located on one side of the raceway in the axial direction; the oil supply unit may include a ring The spacer is set to be adjacent to the side of the fixed ring in the axial direction, and the vibration sensor is installed on the annular spacer; and the spacer has a contact surface that contacts one side in the axial direction The lateral surface of the shoulder is pressed against the lateral surface when the pressure in the axial direction is applied to the spacer and the bearing part. With this configuration, even when the fixed ring and the spacer ring are separate bodies, the vibration of the fixed ring is correctly transmitted to the spacer ring through the application of pressure, and the fixed ring is sensitive to the vibration direction of the vibration sensor. Sex is enhanced.

The fuel supply unit may include a spacer made of metal, the spacer is set as an adjacent fixed ring; and the vibration sensor may be attached via an attachment part made of metal Connected to the spacer, the attachment part is set at the spacer. As mentioned earlier, the vibration sensor detects the vibration of the fixed ring. Metal exhibits lower vibration damping properties than resin. Therefore, with the configuration of the attachment part, the vibration transmitted from the fixed ring to the vibration sensor is not reduced, and the accuracy of the detection by the vibration sensor is enhanced.

The present invention makes it possible to detect the state of lubrication in the bearing part and prevent the occurrence of hot sticking and the like due to shortage of oil.

7: Shaft

8: bearing housing

10: Bearing device

11: Annular space

15: Sliding contact part

17: Inner ring spacer

20: Bearing part

21: inner ring

22: Outer ring

23: rolling element

24: isolation ring

25: inner ring raceway

26: Outer ring raceway

27: Sleeve

28a: ring part

28b: ring part

29: Bar section

30: Shoulder

30a: inner peripheral surface

31: Guide surface

32: Lateral surface

33: contact surface

40: oil supply unit

41: Ring body part

42: storage tank

43: pump

43a: Piezoelectric element

43b: nozzle

44: control unit

44a: amplifier

44b: The first decision circuit

44c: amplifier

44d: Second decision circuit

45: power supply unit

46: substrate

50: temperature sensor

55: Vibration sensor

61: attachment part

The features, advantages, and technical and industrial importance of the exemplary embodiment will be described below with reference to the accompanying drawings, in which similar numbers indicate similar elements, and among them: FIG. 1 is a cross-sectional view showing a bearing device according to an embodiment; 2 is a view of the fuel supply unit seen in the axial direction; Figure 3 is a block diagram illustrating the fuel supply unit; Figure 4 is a graph showing how the detection signal output by the vibration sensor changes over time Fig. 5 is a cross-sectional view of the bearing device; Fig. 6 is a cross-sectional view of the bearing device; Fig. 7 is an explanatory view of the driving voltage applied to the piezoelectric element of the pump; How the output detection signal changes over time.

The bearing device according to the embodiment of the present invention will be described below. Fig. 1 is a cross-sectional view showing a bearing device according to an embodiment of the present invention. The bearing device 10 shown in FIG. 1 supports the spindle (shaft 7) belonging to the spindle device of the machine tool so that the spindle is rotatable and is contained in the bearing housing 8 of the spindle device. In Fig. 1, the shaft 7 and the bearing housing 8 are indicated by alternate long and two short dashed lines. The bearing device 10 can also be applied to devices, machines, and the like that are different from machine tools. In the following description, the direction parallel to the center line of the bearing device 10 will be referred to as the axial direction, and the direction orthogonal to the axial direction will be referred to as the radial direction.

The bearing device 10 includes a bearing part 20 and an 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 spacer ring 24, which holds the plurality of balls 23 and constitutes a ball bearing (rolling bearing). Furthermore, the bearing device 10 includes a cylindrical inner ring spacer 17.

The oil supply unit 40 has an annular shape as a whole, and is provided to adjoin the bearing portion 20 in the axial direction. The oil supply unit 40 according to this embodiment has the function of supplying oil to the bearing portion 20 and also has the function of an outer ring spacer. The structure and function of the fuel supply unit 40 will be described later. Although not shown in the equations, a ring-shaped outer ring spacer made of metal may be set to adjoin one side of the outer ring 22 in the axial direction (hereinafter, referred to as "first side") , And the oil supply unit can be arranged on the inner side of the outer ring spacer in the radial direction.

In this embodiment, the outer ring 22 and the oil supply unit 40 are attached to the bearing The housing 8 prevents the outer ring 22 and the oil supply unit 40 from rotating, and the inner ring 21 and the inner ring spacer 17 rotate with the coaxial rod 7. Accordingly, the outer ring 22 is a fixed ring that does not rotate, and the inner ring 21 is a rotating ring that rotates with the coaxial rod 7.

The inner ring 21 is a cylindrical member fixed to the outer periphery of the shaft 7, and a raceway (hereinafter referred to as the inner ring raceway 25) is provided on the outer periphery of the inner ring 21. In this embodiment, the inner ring 21 and the inner ring spacer 17 are separate bodies. However, although not shown in the drawings, the inner ring 21 and the inner ring spacer 17 may be integrated with each other (that is, may be inseparable from each other). The outer ring 22 is a cylindrical member fixed to the inner peripheral surface of the bearing housing 8, and a raceway (hereinafter referred to as the outer ring raceway 26) is provided on the inner periphery of the outer ring 22. As previously mentioned (although not shown in the drawings), the oil supply unit 40 is a body separated by the ring-shaped outer ring spacer, and is set in the ring-shaped outer ring spacer in the radial direction. In the case of the structure on the side, the outer ring spacer and the outer ring 22 may be integrated with each other (that is, they may be inseparable from each other).

The balls 23 are inserted between the inner ring 21 and the outer ring 22 and roll on the inner ring raceway 25 and the outer ring raceway 26. The spacer ring 24 is ring-shaped, and a plurality of sleeve openings 27 are provided along the circumferential direction thereof. The balls 23 and the spacer ring 24 are provided in the annular space 11, and the annular space 11 is formed between the inner ring 21 and the outer ring 22.

On the whole, the spacer ring 24 is ring-shaped and has an annular portion 28a on the first side surface of the ball 23 in the axial direction, and on the other side surface of the ball 23 in the axial direction (hereinafter referred to as Is the "second side") on the ring portion 28b, and the ring portion 28a and the ring portion 28b are coupled A plurality of bar parts 29 connected to each other. Each set of openings 27 is located between the annular portions 28a and 28b and between the bar portions 29 adjacent to each other in the circumferential direction. One of the balls 23 is accommodated in each of the socket openings 27. Due to this configuration, the spacer ring 24 can hold a plurality of balls 23 separated from each other in the circumferential direction.

In the spacer ring 24, the annular portion 28a on the first side surface (that is, on the side surface of the oil supply unit 40) in the axial direction is constructed for sliding contact with the shoulder 30 of the outer ring 22 via lubricating oil . Therefore, the spacer ring 24 is positioned in the radial direction by the outer ring 22. That is, the bearing portion 20 is a bearing, and the spacer ring 24 is guided in the bearing by the outer ring (that is, guided by the raceway ring). In this embodiment, the outer peripheral surface of the annular portion 28 a is the guide surface 31, which is configured to be in sliding contact with the inner peripheral surface 30 a of the shoulder 30. Therefore, the spacer ring 24 has a guide surface 31 which is configured for sliding contact with a part (shoulder 30) of the outer ring 22 as a fixed ring via lubricating oil. The space between the guide surface 31 of the spacer ring 24 and the shoulder 30 of the outer ring 22 will be referred to as the sliding contact portion 15 hereinafter. The spacer ring 24 is made of resin (for example, made of phenolic resin), and the inner ring 21 and the outer ring 22 are made of steel, such as bearing steel. The ball 23 may be made of steel, such as bearing steel, or may be made of ceramics.

FIG. 2 is a view of the oil supply unit 40 seen in the axial direction (as seen in the direction indicated by the arrow A in FIG. 1). As a whole, the oil supply unit 40 has an annular shape. The oil supply unit 40 according to this embodiment includes an annular body portion 41, a storage tank 42, and a helper Pu 43, vibration sensor 55, temperature sensor 50, control unit 44, and power supply unit 45.

The body portion 41 is an annular member made of metal, for example, and serves as an outer ring spacer for receiving pressure. That is, the pressure in the axial direction is applied to the outer ring spacer (body portion 41) and the outer ring 22. As shown in Figure 5, due to the preload, the axial load (indicated by the arrow F1) acting from the first side in the axial direction to the second side in the axial direction is applied to the outer ring spacer (Body part 41) and the outer ring 22, and the outer ring spacer (body part 41) presses the outer ring 22 in the axial direction.

As shown in FIG. 2, the body part 41 also has the function of accommodating (holding) the frame of the pump 43, the sensors 55 and 50, and the like. In other words, the hollow space is provided in the body part 41. The storage tank 42, the pump 43, the vibration sensor 55, the temperature sensor 50, the control unit 44, and the power supply unit 45 are provided in the hollow space. Therefore, the fuel supply unit 40 including the body portion 41, the storage tank 42, the pump 43, the vibration sensor 55, the temperature sensor 50, the control unit 44, and the power supply unit 45 is constructed as an integrated unit. The vibration sensor 55, the temperature sensor 50, and the control unit 44 may be provided on a single substrate 46. Although not shown in the drawings, the body portion 41 includes an outer cylindrical member made of metal and used as an outer ring spacer for receiving pressure, and an inner cylindrical member made of resin, and Attached to the inner peripheral side of the outer cylindrical member. The hollow space can be provided in the inner cylindrical member. In this case, it is preferable that the vibration sensor 55 will be fixed to the outer cylindrical member via an attachment portion 61 made from metal (see FIG. 6).

In FIG. 2, the storage tank 42 stores lubricating oil and communicates with the pump 43 through the flow channel, so that the lubricating oil is supplied to the pump 43. A holding body (for example, felt or sponge) that holds lubricating oil may be provided in the storage tank 42. The pump 43 includes a piezoelectric element 43a therein. The piezoelectric element 43a operates to change the volume of the internal space of the pump 43, whereby the lubricating oil in the internal space is injected into the annular space 11 from the nozzle 43b (see FIG. 1). Therefore, the pump 43 can supply lubricating oil to the bearing portion 20. When the pump 43 is operated once, several microliters to several nanoliters of lubricating oil are injected. The power supply unit 45 supplies power for operating the pump 43, the vibration sensor 55, and the temperature sensor 50.

The vibration sensor 55 is an acceleration sensor, and detects the vibration of the outer ring 22 as a fixed ring. In this embodiment, the vibration sensor 55 is provided on the base plate 46, and the base plate 46 is fixed to the body portion 41. Therefore, the vibration sensor 55 is configured to detect the vibration of the outer ring 22 through the body portion 41 and the substrate 46. The outer ring 22 and the body portion 41 are in close contact with each other due to the pressure in the axial direction. Therefore, although the outer ring 22 and the body portion 41 are separate bodies, the vibration sensor 55 can detect the vibration of the outer ring 22.

It is preferable that the vibration sensor 55 will be fixed to the body portion 41 via the attachment portion 61 as shown in FIG. 6, which serves as an outer ring spacer. The attachment part 61 according to the present embodiment is a clamp, which is a separate member from the body part 41. The clamp (attachment part 61) is fixed to the body part 41 by a small screw (not shown). The vibration sensor 55 (the substrate for the vibration sensor 55) is fixed to the fixture (attached) by a small screw (not shown) Connect part 61). The attachment part 61 may be a part of the body part 41 instead of a separate member from the body part 41.

In the configuration shown in FIG. 6, the oil supply unit 40 includes a body portion 41 provided adjacent to the outer ring 22, and the body portion 41 functions as a spacer (outer ring spacer). The body part 41 is provided with an attachment part 61. The vibration sensor 55 is attached to the body part 41 via the attachment part 61. In addition, the attachment portion 61 and the body portion 41 are made of metal (steel), and the outer ring 22 is also made of metal (steel). In the configuration shown in FIG. 6, the vibration sensor 55 detects the vibration of the outer ring 22 as previously described. Metal exhibits a lower vibration reduction property than resin, and therefore, the vibration transmitted from the outer ring 22 to the vibration sensor 55 is less reduced, and the accuracy of detection by the vibration sensor 55 is enhanced.

In FIGS. 1 and 2, the temperature sensor 50 is an infrared sensor (radiation thermometer). The balls 23 are in rolling contact with the inner ring raceway 25 and the outer ring raceway 26, and sliding contact with the sleeve 27 of the spacer ring 24. Therefore, the temperature of the balls 23 is very likely to rise. In this way, in this embodiment (see FIG. 1), the detection area of the temperature sensor 50 is set in the area where the ball 23 passes. The temperature sensor 50 measures the temperature (average temperature) of the surface of the ball 23 passing through the detection area. As described so far, the temperature sensor 50 detects the temperature of the portion of the bearing portion 20 that is different from the sliding contact portion 15. In other words, the temperature sensor 50 detects the temperature of a part different from the part detected by the vibration sensor 55 to vibrate.

FIG. 3 is a block diagram illustrating the oil supply unit 40. The control unit 44 is a circuit board including a programmed microcomputer, an arithmetic circuit, and the like. Etc., and obtain the detection signal output by the vibration sensor 55 and the temperature sensor 50. The control unit 44 includes an amplifier 44a that amplifies the output (detection signal) of the vibration sensor 55, and a first decision circuit 44b that executes a decision process based on the amplified signal. Furthermore, the control unit 44 includes an amplifier 44c that amplifies the output (detection signal) of the temperature sensor 50, and a second determination circuit 44d that performs calculations of the temperature gradient and the determination process.

The control unit 44 supplies control signals to the pump 43. The control unit 44 supplies driving power (applies a predetermined voltage) to the piezoelectric element 43a of the pump 43 (see FIG. 2) as a control signal. The pump 43 according to this embodiment is configured to discharge a given amount (minimal amount) of lubricating oil when receiving a control signal (driving voltage). The control unit 44 outputs the control signal to the pump 43 in a given cycle. The cycle is set to be constant during normal time (that is, in a good lubrication state). However, as will be described later when the set conditions are met, the cycle is changed.

In the bearing portion 20 (see FIG. 1), the sliding contact portion 15 between the shoulder 30 of the outer ring 22 and the annular portion 28a of the spacer ring 24, the ball 23 and the inner ring raceway 25 and the outer ring raceway 26 Between the ball 23 and the sleeve opening 27 of the spacer ring 24, the oil supply unit 40 constructed as described above can prevent the occurrence of heat generation and the like. For this purpose, the control performed by the control unit 44 will be described below.

FIG. 4 is a graph showing how the output of the detection signal (first detection signal) from the vibration sensor 55 changes over time. The vibration sensor 55 is an acceleration sensor as previously described, and therefore, the acceleration (the peak value of the acceleration wave) is obtained as the first detection signal. In a state, in The thin film is where the sliding contact portion 15 is formed by lubricating oil (that is, a good lubrication state), and the level of acceleration obtained as the first detection signal is low, in other words, the outer ring 22 The vibration is small (before time t1 in Fig. 4). However, when the thin film of lubricating oil is interrupted at the sliding contact portion 15, the level of acceleration obtained as the first detection signal becomes high (at time t1). In this way, when a shortage of oil occurs in the sliding contact portion 15, a spike vibration waveform (peak waveform) is generated in the outer ring 22. The reason for this is assumed as follows. In the case where a suitable oil film is formed on the sliding contact portion 15, sliding occurs between the shoulder 30 of the outer ring 22 and the guide surface 31 of the spacer ring 24, and the outer ring 22 hardly vibrates. However, when the oil film is interrupted at the sliding contact portion 15 (when a shortage of oil occurs), the guide surface 31 directly hinders the shoulder 30 (collision with the shoulder), and considerable vibration occurs in the outer ring 22 . Therefore, the vibration is detected by the vibration sensor 55.

When the bearing part 20 rotates, the first determination circuit 44b (see FIG. 3) of the control unit 44 continuously obtains the first detection signal (acceleration signal) of the vibration sensor 55, and executes the level of the first detection signal The comparison process with the predetermined threshold α (first threshold). When this level is higher than the threshold α (this condition will be referred to as the first condition hereinafter), the control unit 44 outputs a control signal for reducing the circulation of the discharge of lubricating oil by the pump 43 (that is, Used to cause the control signal to shorten the cycle). For example, when the first condition is met, due to the result of the comparison, the control unit 44 then outputs a control signal to the pump 43, and causes the pump 43 to discharge lubricating oil therefrom. Furthermore, the control unit 44 reduces the circulation of the control signal output to the pump 43 ring. Therefore, the shortage of oil is eliminated. The comparison process can be realized by providing the function of the control unit 44, such as a comparator.

As previously described, when the level of the first detection signal becomes higher than the threshold α once due to the result of the comparison, the condition for outputting the control signal to the pump 43 can be satisfied (see FIG. 4). However, or alternatively, as shown in FIG. 8, when the level of the first detection signal becomes higher than the threshold α multiple times, this condition may be satisfied. In this case, the control unit 44 has the function of a counter. In other words, in FIG. 8, even when the level of the first detection signal becomes higher than the threshold α (at the time t1) once, the control unit 44 cannot output the control signal, and the control unit 44 can After detecting that the level of the first detection signal has become higher than the threshold α (at time t2) twice (multiple times), it outputs a control signal. Therefore, when the level of the first detection signal becomes higher than the threshold α once due to noise, no control signal is output. Therefore, it may enhance the reliability in detecting poor lubrication conditions.

As described so far, the control unit 44 can compare the level of the detection signal of the vibration sensor 55 with the threshold α. When the level is higher than the threshold α as a result of this comparison, the control unit 44 can output a control signal for causing the pump 43 to supply lubricating oil.

As mentioned above, the pump 43 can be controlled only based on the first detection signal of the vibration sensor 55. However, in this embodiment, the pump 43 is controlled by using the second detection signal of the temperature sensor 50. That is, the second determination circuit 44d (see FIG. 3) of the control unit 44 continuously obtains the detection signal (second detection signal) of the temperature sensor 50, that is, the same temperature signal, and executes it based on the detection signal Changes in temperature over time (also That is, the comparison process between the level of the temperature gradient and the predetermined threshold (the second threshold). Then, when the level is higher than the predetermined threshold (this condition will be referred to as the second condition hereinafter), the control unit 44 can output a control signal for reducing the circulation of the discharge of lubricating oil by the pump 43 (That is, the control signal used to cause the cycle to become shorter).

In this embodiment, the control unit 44 is configured to output a control signal to cause the pump 43 to supply lubricating oil by using two conditions, namely the first condition and the second condition in each case. That is, when only one of the first condition and the second condition is satisfied, the control that causes the discharge cycle to be shorter relative to the predetermined value (that is, the control that causes the discharge cycle to be shorter than the predetermined value) is executed And when both the first condition and the second condition are met, the control that causes the discharge cycle to be still shorter than the predetermined value is executed. More specifically, when neither the first condition nor the second condition is satisfied, that is, when it is satisfied in normal time (that is, in a good lubrication state), the pump 43 operates at 1 Hz. However, when only one of the first condition and the second condition is satisfied, the pump 43 is operated at 10 Hz, and when both the first condition and the second condition are satisfied, the pump 43 is operated at 100 Hz.

When a shortage of oil occurs in the bearing portion 20, before the temperature detected by the temperature sensor 50 tends to rise rapidly, the acceleration wave peak in the form of a spike as described earlier (see Figure 4) is usually Will show up. According to this, when the first condition is satisfied, the control that causes the discharge cycle to become shorter with respect to the predetermined value is executed. Furthermore, when the second condition is satisfied thereafter, the control that causes the discharge cycle to be still shorter than the predetermined value is executed.

Therefore, the bearing device 10 (see FIG. 1) according to this embodiment is constructed In order to make the guide surface 31 passing through the spacer ring 24 slide into contact with the shoulder 30 of the outer ring 22 via the lubricant, the spacer ring 24 is positioned by the outer ring 22. Accordingly, heat is extremely likely to be generated in the sliding contact portion 15 between the guide surface 31 of the isolation ring 24 and the shoulder 30 of the outer ring 22. When a shortage of oil (and its signal) occurs due to, for example, the depletion of lubricant in the sliding contact portion 15, the contact state between the guide surface 31 and the shoulder 30 changes, and the change appears as the vibration of the outer ring 22. Therefore, the vibration sensor 55 detects vibration. Therefore, the shortage of oil in the bearing portion 20 (the sliding contact portion 15) (and the indication of the shortage of oil) can be detected based on the vibration of the outer ring 22. That is, the lubrication state in the bearing part 20 can be detected by the vibration sensor 55.

When a shortage of oil occurs in the sliding contact part 15, even if the temperature rise of the sliding contact part 15 is detected, it is difficult to directly detect the temperature rise because the shoulder 30 and the guide surface of the spacer ring 24 The gap between 31 is very small. In other words, because it is difficult to directly detect the temperature of the space between the guide surface 31 and the shoulder 30 by the temperature sensor, the temperature sensor detects the lateral surface of the spacer ring 24 in the axial direction The heat generated between the guide surface 31 and the shoulder 30 has been transferred to the lateral surface. However, in this case, the shortage of oil in the sliding contact portion 15 (here derived from the rise in temperature) is detected indirectly, and therefore, the reactivity and accuracy of this detection may be insufficient. Therefore, in this embodiment, the vibration originating from the change in the contact state between the guide surface 31 and the shoulder 30 caused by the shortage of oil is detected by the vibration sensor 55. Therefore, the reactivity and accuracy of detection are high, and it may increase It is important to detect the oil shortage (and the indication of the oil shortage), that is, the reliability of detecting the lubrication state in the bearing part 20.

As mentioned earlier, in this embodiment, when a shortage of oil occurs in the bearing portion 20, the peak value of the acceleration wave in the form of a spike signal as shown in FIG. 4 is based on the discovery by the vibration sensor 55 It was detected that the finding was that the peak of this wave appeared before the temperature tended to rise rapidly. Therefore, oil shortages (and indications of oil shortages) can be detected at an early stage.

Then, when the amount of lubricating oil in the bearing portion 20 decreases due to, for example, exhaustion, the temperature inside the bearing rises. Therefore, this increase in temperature is detected by the temperature sensor 50, and therefore, the decrease in the amount of lubricating oil is detected. The temperature sensor 50 is provided to detect the temperature of a part (the ball 23) different from the sliding contact part 15. Therefore, in cooperation with the vibration sensor 55, the temperature sensor 50 can further enhance the reliability of the bearing part 20 in detecting the lubrication state.

As described so far, the fuel supply unit 40 includes both the vibration sensor 55 and the temperature sensor 50. Therefore, the control unit 44 can determine whether the first detection signal of the vibration sensor 55 satisfies the first condition (predetermined first condition), and determines whether the second detection signal of the temperature sensor 50 satisfies the second condition (The second condition stipulated). Then, when one of the first condition and the second condition is satisfied, the control unit 44 outputs a control signal for causing the pump 43 to supply lubricating oil. In this embodiment, a signal for reducing the discharge cycle of lubricating oil from the pump 43 is output as a control signal. As mentioned above, the state of lubrication in the bearing part 20 can be double-checked The reliability of detection can be further enhanced.

In the previous embodiment, the control unit 44 can supply driving power (that is, can apply a predetermined voltage) to the piezoelectric element 43a (see FIG. 2) of the pump 43 as a control signal, and according to the vibration sense As a result of the detection performed by the sensor 55 (and/or the temperature sensor 50), the cycle of supplying the driving voltage is further changed (reduced). However, the control unit 44 may perform control other than this. That is, the control unit 44 can supply (apply a predetermined voltage) the driving power used as the control signal to the piezoelectric element 43a of the pump 43 (see FIG. 2), as in the previous embodiment, and can follow The result of the detection performed by the vibration sensor 55 (and/or the temperature sensor 50) is further controlled to change the magnitude of the driving voltage (that is, when the first condition and/or the second condition are satisfied Time). That is, the displacement (operation amount) of the piezoelectric element 43a is increased by increasing the driving voltage P (see FIG. 7) supplied to the piezoelectric element 43a. In FIG. 7, the waveform of the driving voltage before the change is indicated by a broken line, and the waveform of the changed driving voltage is indicated by a solid line. By increasing the displacement amount of the piezoelectric element 43a in this way, the change in the volume of the internal space of the pump 43 can be increased, and the amount of lubricating oil discharged each time can be increased. As a result, if the cycle of supplying the driving voltage is reduced (that is, the cycle system is shortened), the amount of lubricating oil supplied for a given period of time can be increased.

Also in this case, the control unit 44 can output a control signal for in each case, by using two conditions, namely the first condition and the second condition, causing the pump 43 to supply lubricating oil. In other words, control can be Implemented to output a control signal for increasing the driving voltage supplied to the piezoelectric element 43a when only one of the first condition and the second condition is satisfied, and when both the first condition and the second condition are When it is satisfied, a control signal for further increasing the driving voltage is output.

According to the result of the detection performed by the vibration sensor 55 (and/or the temperature sensor 50), the control unit 44 can perform control to increase the temperature of the lubricating oil to be discharged, which is used to increase each time Another control of the amount of lubricating oil discharged by the pump 43. To perform this control, for example, the storage tank 42 (see FIG. 2) may be provided with a heater (not shown). That is, the control unit 44 performs control of the output control signal for operating the heater according to the result of the detection performed by the vibration sensor 55 (and/or the temperature sensor 50) (that is, causing current Flow through the heater control) (that is, when the first condition and/or the second condition are met). When the temperature of the lubricating oil is increased by the heater, the viscosity of the lubricating oil is reduced. Therefore, even when the driving force of the pump 43 is constant, the discharge amount is increased. In this way, the amount of lubricating oil supplied for a given period of time can be increased. After that, the operation of the heater was stopped, and the discharge amount returned to the original amount due to natural cooling.

In the bearing portion 20 according to the present embodiment, as previously described (see FIGS. 1 and 6), the guide surface 31 of the spacer ring 24 is constructed for centering on the first side surface of the outer ring 22 in the axial direction The upper part is in sliding contact with the shoulder 30 via lubricating oil. The oil supply unit 40 is provided on the first side surface of the bearing portion 20 in the axial direction, where the shoulder 30 is presented so that the oil supply unit 40 is adjacent to the bearing portion 20. The vibration sensor 55 is closer to the outer ring 22 in the radial direction (that is, the vibration sensor 55 is closer to the outer ring 22 in the radial direction than the inner ring). The ring 21 is closer to the outer ring 22). In other words, the vibration sensor 55 is located close to the shoulder 30, and the spacer ring 24 is in contact with the shoulder in the axial direction, and is located closer to the inner ring 21 in the radial direction. The position of the outer ring 22. Therefore, with the vibration sensor 55, the sensitivity in the detection of the vibration of the outer ring 22 is enhanced.

FIG. 5 is a cross-sectional view of the bearing device 10 (a view along a cross-sectional surface different from that of FIG. 1). As previously mentioned, the bearing device 10 is used with pressure applied to it in the axial direction. In FIG. 5, the direction of the force used to apply the preload is indicated by arrows F1 and F2. In other words, the body portion 41 of the oil supply unit 40 presses the outer ring 22 of the bearing portion 20 from the first side surface in the axial direction to the second side surface in the axial direction, and the inner ring 21 of the bearing portion 20 is The second side surface in the axial direction is pressed against the first side surface in the axial direction. In this way, pressure in the axial direction is applied to the bearing portion 20.

In this way, in the bearing device 10 according to the present embodiment, as previously described, the outer ring 22 includes the outer ring raceway 26 and the shoulder 30, the balls 23 are in rolling contact with the outer ring raceway, and the shoulder 30 is tied to the shaft It is located on the first side surface of the outer ring raceway 26 in the forward direction. The oil supply unit 40 includes a body portion 41 which is arranged to adjoin the first side surface of the outer ring 22 in the axial direction, and the body portion 41 functions as a spacer. The vibration sensor 55 is mounted on the spacer (body part 41). In the case of the configuration shown in FIG. 6, the vibration sensor 55 is mounted on the attachment part 61, which is attached to the spacer (body part 41). The spacer (body portion 41) has a contact surface 33 in the axial direction in the second side surface (see Figures 2, 5 and 6). The contact surface 33 is on the first side The side surface 32 of the shoulder 30 is surface-contacted in the axial direction, and the side surface 32 is pressed when the pressure in the axial direction is applied to the spacer (body portion 41) and the bearing portion 20. Due to this configuration, although the outer ring 22 and the spacer (body part 41) are separate bodies, the vibration of the outer ring 22 is accurately transmitted to the spacer (body part 41) through the application of pressure, and is sensed by vibration The sensitivity of the vibration detection of the outer ring 22 and the outer ring 22 is enhanced.

As described above, the bearing device 10 according to the present embodiment makes it possible to detect the lubrication state in the bearing portion 20, and by enhancing the reliability in this detection, it is effective to prevent heat generation and sticking and the like on the bearing portion 20. happened.

In the bearing device 10 according to the present embodiment (see FIG. 1), the storage tank 42 (see FIG. 2) is provided in the small space of the oil supply unit 40, and therefore, the capacity of the storage tank 42 is limited. Despite the limited capacity of the storage tank 42, when the amount of lubricating oil consumed increases, it becomes necessary to replenish the storage tank 42 with lubricating oil, and every time maintenance of the replenishing tank 42 with lubricating oil is carried out, the device (machine tool ) Needs to be stopped. As a result, the operation efficiency (production efficiency) is reduced. However, in the bearing device 10 according to this embodiment, when the spike waveform (see Figures 4 and 8) generated in the outer ring 22 is detected by the vibration sensor 55, it is determined to be oily The shortage of oil (and an indication of oil shortage), and a large amount of oil is supplied by pump 43. According to this, the supply of oil does not need to be performed, and therefore the amount of lubricating oil consumed can be reduced. Therefore, there is no need to frequently perform maintenance to replenish the storage tank 42 with lubricating oil, and generally maintenance-free operations can be performed in some cases.

The embodiments disclosed above are exemplary and non-limiting in all respects of. In other words, the bearing device according to the present invention is not limited to the configuration shown in the drawings, and the bearing device according to the present invention may have other configurations within the scope of the present invention.

For example, the spacer ring 24 may have a structure different from the structure shown in the drawing. The spacer ring 24 may be configured to be in sliding contact with a portion of the inner peripheral surface of the outer ring 22. In the configuration shown in FIG. 1, the guide part configured for sliding contact with the outer ring 22 is a surface (guide surface 31 ). However, the guiding part may be a protruding part. The object in sliding contact with the spacer ring 24 may be the inner peripheral surface of the outer ring 22 that is different from the inner peripheral surface 30a of the shoulder 30, and may be a part of the outer ring raceway 26 (note that this part does not include the contact with the ball 23 point). Although not shown in the drawings, the spacer ring 24 may be constructed so that the ring-shaped portion is only provided on the first side surface of the ball 23 in the axial direction (that is, on the side surface of the oil supply unit 40) (that is, on the side surface of the oil supply unit 40). , The spacer ring 24 can be constructed to be used as a so-called raised spacer ring).

In the previous embodiment, the outer ring 22 is a fixed ring, and the outer ring 22 positions the spacer ring 24 in the radial direction, but the opposite configuration may be adopted. That is, the inner ring 21 may be a fixed ring, and the inner ring 21 may position the spacer ring 24 in the radial direction. In this case, the vibration sensor 55 detects the vibration of the inner ring 21. That is, in the bearing portion 20, one of the inner ring 21 and the outer ring 22 may be a rotating ring, and the other of the inner ring 21 and the outer ring 22 may be a fixed ring. The isolation ring 24 may include a guiding part configured to be in sliding contact with a part of the fixed ring through lubricating oil, and the vibration sensor 55 may detect the vibration of the fixed ring.

The bearing part 20 shown in Fig. 1 has an angular ball bearing, but The bearings are not limited to angular ball bearings. The bearing portion 20 may be a deep groove ball bearing. The bearing portion 20 may be a tapered roller bearing, a cylindrical roller bearing, etc. having rollers as roller elements.

In the previous embodiment, the fuel supply unit 40 includes a control unit 44 and a power supply unit 45. However, the control unit 44 and the power supply unit 45 may be installed outside the oil supply unit 40, that is, outside the bearing device 10. In this case, the fuel supply unit 40 and the outside are connected to each other via signal lines or power lines.

In the previous embodiments, the configuration of the pump to discharge lubricating oil in a given cycle has been described as a premise, but the present invention is not limited to this. In other words, the pump can be constructed to discharge lubricating oil every time it is determined by the result of the detection performed by the vibration sensor and/or the temperature sensor, and the pump can be constructed to be used here. The lubricating oil system is required for the inside of the bearing, even when the pump does not regularly discharge the lubricating oil, the lubricating oil is discharged. The frequency of pumping out the lubricating oil can be increased according to the detection result. The amount of lubricating oil discharged during each pumping operation can be increased according to the detection result.

7: Shaft

8: bearing housing

10: Bearing device

11: Annular space

15: Sliding contact part

17: Inner ring spacer

20: Bearing part

21: inner ring

22: Outer ring

23: rolling element

24: isolation ring

25: inner ring raceway

26: Outer ring raceway

27: Sleeve

28a: ring part

28b: ring part

29: Bar section

30: Shoulder

30a: inner peripheral surface

31: Guide surface

40: oil supply unit

41: Ring body part

44: control unit

46: substrate

50: temperature sensor

55: Vibration sensor

Claims (9)

A bearing device includes: a bearing part including an inner ring, an outer ring, a plurality of rolling elements inserted between the inner ring and the outer ring, and a spacer ring holding the plurality of rolling elements, the inner ring and the One of the outer ring is a rotating ring, and the other of the inner ring and the outer ring is a fixed ring; and an oil supply unit which is arranged to adjoin the bearing part in the axial direction, wherein the spacer ring It includes a guide part configured to make sliding contact with a part of the fixed ring via lubricating oil, and the oil supply unit includes a guide part configured to detect sliding between the part of the fixed ring and the guide part A vibration sensor for the vibration of the contact part, a temperature sensor configured to detect the temperature of a part of the bearing part different from the sliding contact part, and a temperature sensor configured to supply the lubricating oil to the bearing part Of the pump. For example, the bearing device of item 1 of the scope of patent application also includes a control unit, which is constructed to compare the level and threshold of the detection signal of the vibration sensor, and output a control signal for when the position When the standard is higher than the threshold, the pump will supply the lubricating oil as a result of the comparison. Such as the bearing device of the first item in the scope of patent application, wherein the temperature sensor detects the temperature of the surface of the plurality of rolling elements. For example, the bearing device of item 1 of the scope of patent application also includes a control unit, which is constructed to determine the first detection of the vibration sensor Whether the test signal meets a predetermined first condition, is used to determine whether the second detection signal of the temperature sensor meets a predetermined second condition, and is used to output a control signal for when the predetermined first condition and When one of the prescribed second conditions is met, the pump is made to supply the lubricating oil. For example, the bearing device of item 4 of the scope of patent application, wherein when only one of the prescribed first condition and the prescribed second condition is satisfied, the control unit executes the lubricating oil produced by the pump The discharge cycle is shorter than the predetermined value; and when both of the predetermined first condition and the predetermined second condition are satisfied, the control unit executes the discharge cycle than the predetermined value. Shorter control. Such as the bearing device of any one of items 1 to 5 in the scope of the patent application, wherein the guide portion of the spacer ring is constructed for contacting the fixed ring on one side surface in the axial direction via the lubricating oil Partial sliding contact; the oil supply unit is arranged on the side surface of the bearing part in the axial direction, so that the oil supply unit is adjacent to the bearing part; and the vibration sensor is compared in the radial direction The rotating ring is set closer to the fixed ring. Such as the bearing device of any one of items 1 to 5 in the scope of patent application, wherein the fixed ring includes a raceway and a shoulder, the plurality of rolling elements are in rolling contact with the race, and the shoulder is attached to the shaft The part located on one side of the raceway in the direction; The oil supply unit includes an annular spacer, which is arranged in the axial direction to be adjacent to the side of the fixed ring, the vibration sensor is installed on the annular spacer; and the spacer has a contact A surface that contacts the lateral surface of the shoulder on the side surface in the axial direction, and presses the lateral surface when pressure in the axial direction is applied to the spacer ring and the bearing part. Such as the bearing device of any one of items 1 to 5 in the scope of patent application, wherein the oil supply unit includes a spacer made of metal, the spacer is set to adjoin the fixed ring; and the vibration sensor is It is attached to the spacer ring via an attachment part made of metal, and the attachment part is provided at the spacer ring. Such as the bearing device of any one of items 1 to 5 in the scope of patent application, wherein the temperature sensor is an infrared sensor.

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