TW201734329A - 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 portion, and an oil supply unit that is disposed adjacent to the bearing portion in the axial direction.

In recent years, various machine tools have been required to have a mandrel that rotates at a higher rate in order to improve machining efficiency and productivity. When the mandrel is rotated at a high speed, the lubricating properties are particularly important in the bearing portion that supports the mandrel. Therefore, there is proposed a bearing device including an oil supply unit which is provided in a spacer which is disposed adjacent to a bearing portion in the axial direction (see Japanese Patent Application Laid-Open No. 2014-219078) (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 storage tank to an 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 oil supply unit is constructed such 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 portion.

When the lubricating oil is evacuated, for example, in the bearing portion to cause a poor lubrication state, the temperature rises. Therefore, with the temperature sensor, the lubrication state in the bearing portion can be detected by detecting the rise in this temperature. 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 the lubricating oil, and therefore, the temperature rise can be suppressed.

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 constructed to measure temperature in the spacer. Therefore, in some cases, the temperature sensor cannot correctly and quickly detect changes in the temperature of the bearing portion. Accordingly, when the temperature has risen due to the shortage of oil in the bearing portion, the detection of the temperature rise can be delayed. As a result, heat build-up or the like can occur in the bearing portion.

The present invention provides a bearing device which can prevent occurrence of seizure due to shortage of oil in a bearing portion, and the like.

One aspect of the invention relates to a bearing arrangement. The bearing device includes a bearing portion including an inner ring, an outer ring, a plurality of rolling elements inserted between the inner ring and the outer ring, and an isolating ring holding the plurality of rolling elements, one of the inner ring and the outer ring rotating Ring, and the other of the inner and outer rings is fixed And a fuel supply unit configured to adjoin the bearing portion in the axial direction. The spacer ring includes a guiding portion configured to be in sliding contact with a portion of the fixing ring via the lubricating oil, and the oil supply unit includes a vibration sensor configured to detect vibration of the fixing ring, and configured to be used for Lubricating oil is supplied to the pump of the bearing part.

The bearing assembly is constructed such that the leading portion of the spacer ring is in sliding contact with a portion of the retaining ring via the lubricating oil, and the spacer ring is thereby positioned by the retaining ring. Accordingly, it is highly probable that the thermal system is generated at the sliding contact portion between the guiding portion of the spacer ring and a portion of the fixing ring. When a shortage of oil (and an indication of a shortage of oil) occurs due to depletion of the lubricating oil in the sliding contact portion, the contact state between the guiding portion of the spacer ring and the portion of the fixing ring changes, and the change appears to be fixed. The vibration of the ring. Therefore, the vibration sensor of the oil 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 heat build-up due to shortage of oil and the like.

When the shortage of oil occurs in a portion of the stationary ring, the inventors of the present invention have found that a peak vibration waveform (peak waveform) is generated in the stationary ring. Therefore, the bearing device may include a control unit 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 comparison As a result, the pump supplies lubricant. With this configuration, oil shortages (and indications of oil shortages) can be detected at an early stage. For example, in the case where the pump is configured to supply lubricating oil to the bearing portion in a given cycle, the signal used to reduce the given cycle (ie, the signal used to cause a given cycle shortage) can be used. As a control signal (i.e., the pump can be configured to supply lubricating oil to the bearing portion in a given cycle, and the control signal can be a signal for reducing a given cycle). Alternatively, a signal for increasing the amount of lubricating oil discharged by the pump may be used as the control signal (i.e., 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 a temperature of a portion of the bearing portion, a portion different from a sliding contact portion between the portion of the retaining ring and the guiding portion. When the amount of the lubricating oil is reduced due to, for example, the exhaustion of the bearing portion, the temperature inside the bearing rises. Therefore, the temperature sensor detects this rise in temperature, and accordingly, a decrease in the amount of lubricating oil can be detected. Furthermore, the temperature sensor detects a temperature different from a portion of the sliding contact portion. Therefore, in conjunction with the vibration sensor, the temperature sensor can further enhance 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 a predetermined first condition, and is used to determine whether the second detection signal of the temperature sensor satisfies the predetermined condition And a condition for outputting a control signal for causing the pump to supply the 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 portion can be further enhanced. For example, in the case where the pump is configured to supply lubricating oil to the bearing portion in a given cycle, the signal for reducing the given cycle (ie, the signal used to cause a given cycle shortage) can be used as the control signal. (That is, the pump can be configured to supply lubricating oil to the bearing portion in a given cycle, and the control signal can be a signal for reducing a given cycle). Or, for adding The signal of the amount of lubricating oil discharged by the pump can be used as a control signal (i.e., the control signal can be a signal for increasing the amount of lubricating oil discharged by the pump). The first condition that is set may be a condition that the level of the first detection signal is higher than the first threshold; and based on the second detection signal, the second condition that is set may be a level of change in temperature with time. A condition that is above a second threshold.

The guiding portion of the spacer ring may be configured to be in sliding contact with a portion of the fixing ring on one side in the axial direction via the lubricating oil; the oil supply unit may be disposed on one side of the bearing portion in the axial direction, so that The oil unit is adjacent to the bearing portion; and the vibration sensor can be set closer to the fixed ring in the radial direction than the rotating ring. With this configuration, the sensitivity of the fixing ring in the direction of vibration of the vibration sensor is enhanced.

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

The oil supply unit may include a spacer made of metal, the spacer is configured to be adjacent to the fixing ring; and the vibration sensor may be attached to the attachment portion made of metal Connected to the spacer, the attachment portion is attached to the spacer. As previously described, the vibration sensor detects the vibration of the stationary ring. Metals exhibit lower vibration-attenuating properties than resins. Therefore, with the configuration of the attachment portion, the vibration transmitted from the fixed ring to the vibration sensor is less reduced, and the accurate performance by the detection of the vibration sensor is enhanced.

The present invention makes it possible to detect the lubrication state of the bearing portion and prevent the occurrence of heat build-up due to shortage of oil and the like.

7‧‧‧ shaft

8‧‧‧ bearing housing

10‧‧‧ bearing device

11‧‧‧Circle space

15‧‧‧Sliding contact

17‧‧‧ Inner ring

20‧‧‧ bearing part

21‧‧‧ Inner Ring

22‧‧‧Outer Ring

23‧‧‧ rolling elements

24‧‧‧Isolation ring

25‧‧‧ Inner Ring Raceway

26‧‧‧Outer ring raceway

27‧‧‧ mouth

28a‧‧‧ring section

28b‧‧‧ring section

29‧‧‧ sticks

30‧‧‧ shoulder

30a‧‧‧ inner peripheral surface

31‧‧‧ Guide surface

32‧‧‧ lateral surface

33‧‧‧Contact surface

40‧‧‧ Oil supply unit

41‧‧‧Circular body part

42‧‧‧ storage tank

43‧‧‧

43a‧‧‧Piezoelectric components

43b‧‧‧Nozzle

44‧‧‧Control unit

44a‧‧Amplifier

44b‧‧‧First decision circuit

44c‧‧Amplifier

44d‧‧‧Second decision circuit

45‧‧‧Power unit

46‧‧‧Substrate

50‧‧‧temperature sensor

55‧‧‧Vibration sensor

61‧‧‧ Attachment

The features, advantages, and technical and industrial advantages of the exemplary embodiments are described below with reference to the accompanying drawings, wherein like numerals indicate like elements, and FIG. 1 is a cross-sectional view showing a bearing device according to an embodiment; 2 is a view of the oil supply unit seen in the axial direction; FIG. 3 is a block diagram illustrating the oil supply unit; and FIG. 4 is a graph showing how the detection signal outputted by the vibration sensor changes with time; Figure 5 is a cross-sectional view of the bearing device; Figure 6 is a cross-sectional view of the bearing device; Figure 7 is an explanatory view of the driving voltage applied to the piezoelectric element of the pump; and Figure 8 is a graph showing the output by the vibration sensor How the detection signal changes over time.

A bearing device according to an embodiment of the present invention will be described below. 1 is a cross-sectional view showing a bearing device in accordance with an embodiment of the present invention. The bearing device 10 shown in Fig. 1 supports a spindle (shaft 7) belonging to the spindle device of the machine tool such that the spindle is rotatable and housed in the bearing housing 8 of the spindle device. In Figure 1, the shaft 7 and the bearing housing 8 are indicated by alternating long and two short dashed lines. The bearing device 10 can also be applied to devices, machines, and the like that are different from the machine tool. 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 portion 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 an isolating ring 24 that holds a plurality of balls 23 and constitutes a ball bearing (rolling bearing). Further, 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 disposed to adjoin the bearing portion 20 in the axial direction. The oil supply unit 40 according to the present embodiment has a function of supplying oil to the bearing portion 20 and also has an outer ring spacer. The organization and function of the oil supply unit 40 will be described later. Although not shown in the drawings, an annular outer ring spacer made of metal may be disposed adjacent to one side of the outer ring 22 in the axial direction (hereinafter, referred to as a "first side"), And the oil supply unit can be disposed on the inner side surface of the outer ring spacer in the radial direction.

In the present embodiment, the outer ring 22 and the oil supply unit 40 are attached to the bearing The outer casing 8 is such that the outer ring 22 and the oil supply unit 40 cannot rotate, 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 fixed to a cylindrical member at the outer periphery of the shaft 7, and a raceway (hereinafter referred to as an inner ring raceway 25) is provided on the outer periphery of the inner ring 21. In the present 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 mutually integrated (i.e., 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 an outer ring raceway 26) is attached to the inner periphery of the outer ring 22. As previously described (although not shown in the drawings), the oil supply unit 40 is a body separated by an annular outer ring spacer and is disposed in the annular outer ring spacer in the radial direction. In the case of the configuration on the side, the outer ring spacer and the outer ring 22 may be mutually integrated (i.e., may be inseparable from each other).

The ball 23 is inserted between the inner ring 21 and the outer ring 22, and rolls on the inner ring raceway 25 and the outer ring raceway 26. The spacer ring 24 is annular and a plurality of sleeves 27 are provided along its circumferential direction. 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.

In a holistic manner, the spacer ring 24 is annular and has an annular portion 28a on the first side of the ball 23 in the axial direction and the other side of the ball 23 in the axial direction (hereinafter referred to as " The annular portion 28b on the second side") and the annular portion 28a and the annular portion 28b are coupled A plurality of bar portions 29 are connected to each other. Each of the sets of ports 27 is located between the annular portions 28a and 28b and between the bar portions 29 adjoining each other in the circumferential direction. One of the balls 23 is housed in each of the sleeves 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 in the axial direction (i.e., on the side of the oil supply unit 40) is configured for sliding contact with the shoulder 30 of the outer ring 22 via the 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 by the outer ring in the bearing (i.e., guided by the raceway ring). In the present embodiment, the outer peripheral surface of the annular portion 28a is a guiding surface 31 that is configured for sliding contact with the inner peripheral surface 30a of the shoulder portion 30. Thus, the spacer ring 24 has a guiding surface 31 that is configured for sliding contact with a portion (shoulder 30) of the outer ring 22 that is a retaining 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 hereinafter be referred to as a sliding contact portion 15. The spacer ring 24 is made of a resin (for example, made of a phenol resin), and the inner ring 21 and the outer ring 22 are made of steel, such as bearing steel. The balls 23 may be made of steel, such as bearing steel, or may be made of ceramic.

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). Overall, the oil supply unit 40 has an annular shape. The oil supply unit 40 according to the embodiment includes an annular body portion 41, a storage tank 42, and a gang The pump 43, the vibration sensor 55, the temperature sensor 50, the control unit 44, and the power supply unit 45.

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

As shown in Fig. 2, the body portion 41 also has the function of housing (holding) the chassis 43, the sensors 55 and 50, and the like. In other words, the hollow space is provided in the body portion 41. The reservoir 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 a hollow space. Therefore, the oil supply unit 40 including the body portion 41, the reservoir 42, the pump 43, the vibration sensor 55, the temperature sensor 50, the control unit 44, and the power supply unit 45 is constructed to be an integral unit. The vibration sensor 55, the temperature sensor 50, and the control unit 44 may be disposed on a single substrate 46. Although not shown in the drawings, the body portion 41 includes an outer cylindrical member which is made of metal and serves 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. A hollow space can be provided in the inner cylindrical member. In this case, it is preferred that the vibration sensor 55 will be fixed to the outer cylindrical member via the attachment portion 61 made of metal (see Fig. 6).

In FIG. 2, the reservoir 42 stores lubricating oil and communicates with the pump 43 through a flow passage such that lubricating oil is supplied to the pump 43. A holding body (e.g., felt or sponge) holding the lubricating oil may be provided in the reservoir 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 by the nozzle 43b (see Fig. 1). Therefore, the pump 43 can supply the lubricating oil to the bearing portion 20. When the pump 43 is operated once, several oils that are slightly raised to several nanoliters 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 the present embodiment, the vibration sensor 55 is attached to the substrate 46, and the substrate 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 preferred that the vibration sensor 55 will be secured to the body portion 41 via the attachment portion 61 as shown in Figure 6, which acts as an outer ring spacer. The attachment portion 61 according to the present embodiment is a jig that is a member separate from the body portion 41. The jig (attachment portion 61) is fixed to the body portion 41 by a small screw (not shown). The vibration sensor 55 (the substrate for the vibration sensor 55) is fixed to the jig by a small screw (not shown) (attached) Connect part 61). The attachment portion 61 can be a portion of the body portion 41 instead of a member that is separate from the body portion 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 portion 41 is provided with an attachment portion 61. The vibration sensor 55 is attached to the body portion 41 via the attachment portion 61. Further, 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. The metal exhibits a lower vibration attenuating property than the resin, and therefore, the vibration transmitted from the outer ring 22 to the vibration sensor 55 is less reduced, and the accurate performance detected by the vibration sensor 55 is enhanced.

In FIGS. 1 and 2, the temperature sensor 50 is an infrared sensor (radiation thermometer). The ball 23 is in rolling contact with the inner ring raceway 25 and the outer ring raceway 26, and is in sliding contact with the sleeve 27 of the spacer ring 24. Therefore, the temperature of the balls 23 is highly likely to rise. Thus, in the present embodiment (see FIG. 1), the detection area of the temperature sensor 50 is set in the area through which the balls 23 pass. 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 portion different from the portion where the vibration sensor 55 detects the vibration.

Figure 3 is a block diagram showing the oil supply unit 40. The control unit 44 is composed of a substrate circuit including a programmed microcomputer, an arithmetic circuit, and the like. The components are configured to obtain the detection signals 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 performs 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 decision circuit 44d that performs temperature gradient and calculation of the decision process.

The control unit 44 supplies a control signal to the pump 43. The control unit 44 supplies the driving power (applying a predetermined voltage) to the piezoelectric element 43a of the pump 43 (see Fig. 2) as a control signal. The pump 43 according to the present embodiment is constructed to discharge a given amount (minor amount) of lubricating oil when receiving a control signal (drive voltage). The control unit 44 outputs a control signal to the pump 43 in a given cycle. The cycle is set to be constant during normal time (ie, in a good lubrication state). However, as will be described later, when the set conditions are satisfied, the loop is changed.

In the bearing portion 20 (see Fig. 1), the sliding contact portion 15 between the shoulder portion 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 and between the ball 23 and the sleeve 27 of the spacer ring 24, the oil supply unit 40 constructed as described above can prevent the generation of heat build-up and the like. For this purpose, the control performed by control unit 44 will be described below.

FIG. 4 is a graph showing how the detection signal (first detection signal) output from the vibration sensor 55 changes over time. The vibration sensor 55 is an acceleration sensor as described earlier, and therefore, the acceleration (acceleration wave peak) is taken as the first detection signal. In a state, in The film is at a position where the sliding contact portion 15 is formed by the 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 system is small (before time t1 in Fig. 4). However, when the film of the 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 at the sliding contact portion 15, a spike signal 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 in the sliding contact portion 15, the sliding occurs between the shoulder 30 of the outer ring 22 and the guiding 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 guiding surface 31 directly obstructs the shoulder 30 (collision with the shoulder), and a considerable vibration occurs in the outer ring 22 . Therefore, the vibration is detected by the vibration sensor 55.

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

As described earlier, when the level of the first detection signal becomes higher than the threshold α by the result of the comparison, the condition for outputting the control signal to the pump 43 can be satisfied (see Fig. 4). However, or as shown in FIG. 8, this condition can be satisfied when the level of the first detection signal becomes higher than the threshold value a plurality of times. In this case, 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), the control unit 44 cannot output the control signal, and the control unit 44 can It outputs a control signal after detecting that the level of the first detection signal has become higher than the threshold α (at time t2) twice (multiple times). Therefore, when the level of the first detection signal becomes higher than the threshold α once due to the noise, no control signal is output. Therefore, it is possible to 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 due to the result of this comparison, the control unit 44 can output a control signal for causing the pump 43 to supply the lubricating oil.

As described above, the pump 43 can be controlled based only on the first detection signal of the vibration sensor 55. However, in the present embodiment, the pump 43 is controlled by the second detection signal of the temperature sensor 50. That is, the second determining 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 performs the detection based on the detection signal. Temperature changes over time (also That is, the process of comparing the level of the temperature gradient with the predetermined threshold (second threshold). Then, when the level is higher than a predetermined threshold (this condition will be referred to as a second condition hereinafter), the control unit 44 can output a control signal for reducing the circulation of the lubricating oil by the pump 43. (ie, the control signal used to cause the cycle to become shorter).

In the present embodiment, the control unit 44 is configured to output a control signal for causing 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 become shorter with respect to the set value (that is, the control that causes the discharge cycle to be shorter than the set value) is performed. And when both the first condition and the second condition are satisfied, the control that causes the discharge cycle to be still shorter than the set value is performed. More specifically, the pump 43 operates at 1 Hz when it is neither the first condition nor the second condition, i.e., in normal time (i.e., in a good lubrication state). However, when only one of the first condition and the second condition is satisfied, the pump 43 operates at 10 Hz, and when both the first condition and the second condition are satisfied, the pump 43 operates 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 peak value of the acceleration wave in the form of a spike signal as previously described (see Fig. 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 performed. Further, when the second condition is thereafter satisfied, the control that causes the discharge cycle to be still shorter than the set value is performed.

Therefore, the bearing device 10 (see FIG. 1) according to the present embodiment is constructed In order for the guiding surface 31 passing through the spacer ring 24 to be in sliding contact with the shoulder 30 of the outer ring 22 via the lubricating oil, the spacer ring 24 is positioned by the outer ring 22. Accordingly, the heat electrode may be generated at the sliding contact portion 15 between the guide surface 31 of the spacer ring 24 and the shoulder portion 30 of the outer ring 22. When the shortage of oil (and its signal) occurs due to the exhaustion of the lubricating oil such as in the sliding contact portion 15, the contact state between the guiding surface 31 and the shoulder portion 30 changes, and the change appears as the vibration of the outer ring 22. Therefore, the vibration sensor 55 detects the vibration. Therefore, the shortage of oil in the bearing portion 20 (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 of the bearing portion 20 can be detected by the vibration sensor 55.

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

As previously described, in the present embodiment, when a shortage of oil occurs in the bearing portion 20, the peak 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. As detected, this finding is due to the peak of the wave before the temperature tends to rise rapidly. Therefore, oil shortages (and indications of oil shortages) can be detected at an early stage.

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

As described so far, the oil 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 (the first condition set), and determines whether the second detection signal of the temperature sensor 50 satisfies the second condition. (Set second condition). 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 the lubricating oil. In the present embodiment, a signal for reducing the discharge cycle of the lubricating oil from the pump 43 is output as a control signal. As described above, the lubrication state in the bearing portion 20 can be double-detected The measurement and the reliability of the detection can be further enhanced.

In the foregoing embodiment, the control unit 44 can supply the driving power (that is, a predetermined voltage can be applied) to the piezoelectric element 43a (see FIG. 2) of the pump 43 as a control signal, and according to the sense of vibration The result of the detection performed by the detector 55 (and/or the temperature sensor 50) further changes (reduces) the cycle of supplying the drive voltage. However, control unit 44 may perform control that is different therefrom. That is, the control unit 44 can supply (apply a predetermined voltage) as the driving power of the control signal to the piezoelectric element 43a of the pump 43 (see FIG. 2), as in the previous embodiment, and can follow The control of changing the magnitude of the driving voltage is further performed by the result of the detection performed by the vibration sensor 55 (and/or the temperature sensor 50) (that is, the satisfaction of the first condition and/or the second condition) Time). That is, the displacement amount (operating 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 manner, the variation in the volume of the internal space of the pump 43 can be increased, and the amount of the lubricating oil discharged each time can be increased. As a result, in the case where the cycle of supplying the driving voltage is reduced (that is, the cycle system becomes short), the amount of the lubricating oil supplied for a given period of time can be increased.

Also in this case, the control unit 44 may output a control signal for causing the pump 43 to supply the lubricating oil by using the two conditions, that is, the first condition and the second condition, in each case. In other words, control can be Executing to output a control signal for increasing a 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 satisfied, a control signal for further increasing the driving voltage is output.

According to the result of the detection by the vibration sensor 55 (and/or the temperature sensor 50), the control unit 44 can perform control for raising the temperature of the lubricating oil to be discharged, as Another control of the amount of lubricant discharged from the pump 43. To perform this control, for example, the reservoir 42 (see Fig. 2) can be provided with a heater (not shown). That is, the control unit 44 performs control of the output control signal for operating the heater in accordance with the result of the detection by the vibration sensor 55 (and/or the temperature sensor 50) (ie, causing current Flow through the control of the heater) (ie, when the first condition and/or the second condition are satisfied). When the temperature of the lubricating oil is raised 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. As such, 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 was 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 use in the axial direction on the first side of the outer ring 22. The sliding contact is made with the shoulder 30 via the lubricating oil. The oil supply unit 40 is disposed on the first side of the bearing portion 20 in the axial direction, where the shoulder portion 30 is presented such 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 in the radial direction compared to the inner Ring 21 is closer to outer ring 22). In other words, the vibration sensor 55 is disposed at a position close to the shoulder 30, and the spacer ring 24 is in contact with the shoulder in the axial direction, and is disposed closer to the inner ring 21 in the radial direction. The position of the ring 22. Therefore, by the vibration sensor 55, the sensitivity in the detection of the vibration of the outer ring 22 is enhanced.

Figure 5 is a cross-sectional view of the bearing device 10 (viewed along a different cutaway surface from Figure 1). As previously described, the bearing device 10 is used with the pressure applied thereto in the axial direction. In Figure 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 in the axial direction toward the second one of the axial directions, and the inner ring 21 of the bearing portion 20 is oriented by the axial direction The second side of the pressure is pressed toward the first side in the axial direction. As such, the pressure in the axial direction is applied to the bearing portion 20.

Thus, 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 portion 30, the ball 23 is in rolling contact with the outer ring raceway, and the shoulder portion 30 is tied to the axis. The direction is centered on the first side of the outer ring raceway 26. The oil supply unit 40 includes a body portion 41 that is disposed adjacent to the first side 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 portion 41). In the case of the configuration shown in Fig. 6, the vibration sensor 55 is mounted on the attachment portion 61 which is attached to the spacer (the body portion 41). The spacer (body portion 41) has a contact surface 33 in the axial direction in the second side (see FIGS. 2, 5 and 6). The contact surface 33 is on the first side The axial direction is in surface contact with the lateral surface 32 of the shoulder 30, and the lateral 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 (the body portion 41) are separate bodies, the vibration of the outer ring 22 is accurately transmitted to the spacer (the body portion 41) by the application of pressure, and is sensed by vibration. The sensitivity of the detection of the vibration of 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 of the bearing portion 20, and effectively prevent the occurrence of heat build-up and the like in the bearing portion 20 by enhancing the reliability in this detection. happened.

In the bearing device 10 according to the present embodiment (see Fig. 1), the reservoir 42 (see Fig. 2) is provided in the small space of the oil supply unit 40, and therefore, the capacity of the reservoir 42 is limited. Despite the limited capacity of the storage tank 42, as the amount of lubricating oil consumed increases, it becomes necessary to replenish the storage tank 42 with lubricating oil, and each time maintenance of the lubricating oil replenishing storage tank 42 is performed, the apparatus (tool machine ) needs to be stopped. As a result, the operation efficiency (production efficiency) is reduced. However, in the bearing device 10 according to the present embodiment, when the spike signal waveform (see Figs. 4 and 8) generated in the outer ring 22 is detected by the vibration sensor 55, it is determined to be oily. The shortage (and the indication of shortage of oil), and a large number of oil systems are supplied by the pump 43. Accordingly, the supply of oil does not need to be performed, and thus the amount of lubricating oil consumed can be reduced. Therefore, maintenance of the reservoir 42 with the lubricating oil need not be performed from time to time, and substantially maintenance-free operation can be performed in some cases.

The embodiments disclosed above are exemplary and non-restrictive 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 can have a configuration that is different from the configuration shown in the figures. The spacer ring 24 can be configured for partial sliding contact with one of the inner peripheral surfaces of the outer ring 22. In the configuration shown in Fig. 1, a guide portion surface (guide surface 31) for sliding contact with the outer ring 22 is constructed. However, the guiding portion may be a protruding portion. The object in sliding contact with the spacer ring 24 may be an inner peripheral surface of the outer ring 22 that is different from the inner peripheral surface 30a of the shoulder 30 and may be part of the outer ring raceway 26 (note that this portion does not include contact with the ball 23) point). Although not shown in the drawings, the spacer ring 24 may be constructed such that the annular portion is provided on the first side of the ball 23 only in the axial direction (i.e., on the side of the oil supply unit 40) (i.e., The spacer ring 24 can be constructed to act as a so-called raised isolation ring).

In the previous embodiment, the outer ring 22 is a retaining ring and the outer ring 22 positions the spacer ring 24 in a radial direction, but the opposite configuration may be employed. That is, the inner ring 21 can be a stationary ring and the inner ring 21 can 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 spacer ring 24 can include a guide portion configured to be in sliding contact with a portion of the stationary ring via the lubricating oil, and the vibration sensor 55 can detect the vibration of the stationary ring.

The bearing portion 20 shown in Figure 1 is an angular ball bearing, but Bearings are not limited to angular ball bearings. The bearing portion 20 can be a deep groove ball bearing. The bearing portion 20 may be a tapered roller bearing having a roller as a roller element, a cylindrical roller bearing or the like.

In the foregoing embodiment, the oil 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 can be mounted outside the oil supply unit 40, that is, outside the bearing unit 10. In this case, the oil supply unit 40 and the outer side are connected to each other via a signal line or a power line.

In the foregoing embodiments, the configuration in which the pump discharges the lubricating oil in a given cycle has been described as a premise, but the present invention is not limited thereto. In other words, the pump can be configured to determine the discharge of the lubricant each time it is detected by the vibration sensor and/or the temperature sensor, and the pump can be constructed for use herein. The lubricating oil is required for the inside of the bearing, and the lubricating oil is discharged even when the pump does not periodically discharge the lubricating oil. The frequency at which the pump discharges the lubricant can be increased according to the detection result. The amount of lubricant that is discharged during each pump operation can be increased according to the detection result.

7‧‧‧ shaft

8‧‧‧ bearing housing

10‧‧‧ bearing device

11‧‧‧Circle space

15‧‧‧Sliding contact

17‧‧‧ Inner ring

20‧‧‧ bearing part

21‧‧‧ Inner Ring

22‧‧‧Outer Ring

23‧‧‧ rolling elements

24‧‧‧Isolation ring

25‧‧‧ Inner Ring Raceway

26‧‧‧Outer ring raceway

27‧‧‧ mouth

28a‧‧‧ring section

28b‧‧‧ring section

29‧‧‧ sticks

30‧‧‧ shoulder

30a‧‧‧ inner peripheral surface

31‧‧‧ Guide surface

40‧‧‧ Oil supply unit

41‧‧‧Circular body part

44‧‧‧Control unit

46‧‧‧Substrate

50‧‧‧temperature sensor

55‧‧‧Vibration sensor

Claims (8)

A bearing device characterized by comprising: a bearing portion (20) comprising an inner ring (21), an outer ring (22), a plurality of rollings inserted between the inner ring (21) and the outer ring (22) An element (23), and an isolating ring (24) holding the plurality of rolling elements (23), wherein one of the inner ring (21) and the outer ring (22) is a rotating ring, and the inner ring (21) And the other of the outer ring (22) is a fixing ring; and an oil supply unit (40) is disposed adjacent to the bearing portion (20) in the axial direction, wherein the spacer ring (24) includes a guide Partially configured to be in sliding contact with a portion of the retaining ring via lubricating oil, and the oil supply unit (40) includes a vibration sensor (55) configured to detect vibration of the retaining ring, and A pump (43) for supplying the lubricating oil to the bearing portion (20) is constructed. The bearing device of claim 1, further comprising: a control unit (44) configured to compare the level and threshold of the detection signal of the vibration sensor (55), and output A control signal for causing the pump (43) to supply the lubricating oil as a result of the comparison when the level is above the threshold. The bearing device of claim 1, wherein the oil supply unit (40) further comprises a temperature sensor (50) configured to detect a temperature of a portion of the bearing portion (20), the portion being different from a sliding contact portion between the portion of the retaining ring and the guiding portion. The bearing device of claim 3, further comprising a control unit (44) configured to determine whether the first detection signal of the vibration sensor (55) satisfies the first condition set, for Determining whether the second detection signal of the temperature sensor (50) satisfies a predetermined second condition, and is configured to output a control signal for when the predetermined first condition and the set second condition are When one is satisfied, the pump (43) is supplied with the lubricating oil. The bearing device of claim 4, wherein: the predetermined first condition is a condition that a level of the first detection signal is higher than a first threshold; and the predetermined second condition is based on the second The condition that the temperature of the signal is detected to be higher than the second threshold value with time. The bearing device of any one of claims 1 to 5, wherein the guiding portion of the spacer ring (24) is configured to pass the lubricating oil on the one side in the axial direction and the retaining ring The oil supply unit (40) is disposed on the one side of the bearing portion (20) in the axial direction such that the oil supply unit (40) is adjacent to the bearing portion (20); And the vibration sensor (55) is disposed closer to the fixed ring than the rotating ring in the radial direction. A bearing device according to any one of claims 1 to 5, wherein: The retaining ring includes a raceway and a shoulder, the plurality of rolling elements (23) are in rolling contact with the raceway, and the shoulder is located in the axial direction as the portion on one side of the raceway The oil supply unit (40) includes an annular spacer which is disposed adjacent to a side of the fixing ring in the axial direction, and the vibration sensor (55) is mounted on the annular spacer; The spacer has a contact surface on which the lateral surface of the shoulder is contacted in the axial direction and is pressed when a pressure in the axial direction is applied to the spacer and the bearing portion (20) Press the lateral surface. The bearing device of any one of claims 1 to 5, wherein: the oil supply unit (40) comprises a spacer made of metal, the spacer being disposed adjacent to the fixing ring; and the vibration A sensor (55) is attached to the spacer via an attachment portion made of metal, the attachment portion being attached to the spacer.