US10385844B2 - Abnormal discharge detection device and abnormal discharge detection method - Google Patents
Abnormal discharge detection device and abnormal discharge detection method Download PDFInfo
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- US10385844B2 US10385844B2 US15/641,574 US201715641574A US10385844B2 US 10385844 B2 US10385844 B2 US 10385844B2 US 201715641574 A US201715641574 A US 201715641574A US 10385844 B2 US10385844 B2 US 10385844B2
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- 230000002159 abnormal effect Effects 0.000 title claims abstract description 47
- 238000001514 detection method Methods 0.000 title claims abstract description 33
- 239000012530 fluid Substances 0.000 claims abstract description 41
- 238000005259 measurement Methods 0.000 claims abstract description 39
- 238000003860 storage Methods 0.000 claims abstract description 10
- 230000007423 decrease Effects 0.000 claims abstract description 7
- 238000000034 method Methods 0.000 claims description 15
- 230000008859 change Effects 0.000 claims description 7
- 238000007599 discharging Methods 0.000 claims description 4
- 239000000314 lubricant Substances 0.000 abstract description 14
- 230000005856 abnormality Effects 0.000 description 24
- 238000005096 rolling process Methods 0.000 description 10
- 230000014509 gene expression Effects 0.000 description 8
- 230000005540 biological transmission Effects 0.000 description 7
- 230000008569 process Effects 0.000 description 5
- 230000002950 deficient Effects 0.000 description 3
- 239000000470 constituent Substances 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 238000003825 pressing Methods 0.000 description 2
- 238000004891 communication Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000010348 incorporation Methods 0.000 description 1
- 238000005461 lubrication Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
Images
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B51/00—Testing machines, pumps, or pumping installations
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B17/00—Pumps characterised by combination with, or adaptation to, specific driving engines or motors
- F04B17/03—Pumps characterised by combination with, or adaptation to, specific driving engines or motors driven by electric motors
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B43/00—Machines, pumps, or pumping installations having flexible working members
- F04B43/02—Machines, pumps, or pumping installations having flexible working members having plate-like flexible members, e.g. diaphragms
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B43/00—Machines, pumps, or pumping installations having flexible working members
- F04B43/02—Machines, pumps, or pumping installations having flexible working members having plate-like flexible members, e.g. diaphragms
- F04B43/04—Pumps having electric drive
- F04B43/043—Micropumps
- F04B43/046—Micropumps with piezoelectric drive
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C2202/00—Solid materials defined by their properties
- F16C2202/30—Electric properties; Magnetic properties
- F16C2202/36—Piezoelectric
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C2233/00—Monitoring condition, e.g. temperature, load, vibration
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C33/00—Parts of bearings; Special methods for making bearings or parts thereof
- F16C33/30—Parts of ball or roller bearings
- F16C33/66—Special parts or details in view of lubrication
- F16C33/6637—Special parts or details in view of lubrication with liquid lubricant
- F16C33/6659—Details of supply of the liquid to the bearing, e.g. passages or nozzles
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C33/00—Parts of bearings; Special methods for making bearings or parts thereof
- F16C33/30—Parts of ball or roller bearings
- F16C33/66—Special parts or details in view of lubrication
- F16C33/6637—Special parts or details in view of lubrication with liquid lubricant
- F16C33/6659—Details of supply of the liquid to the bearing, e.g. passages or nozzles
- F16C33/667—Details of supply of the liquid to the bearing, e.g. passages or nozzles related to conditioning, e.g. cooling, filtering
Definitions
- the present invention relates to abnormal discharge detection devices and abnormal discharge detection methods, and more particularly to devices and methods for detecting an abnormal fluid discharge operation in a fluid supply device using a piezoelectric element.
- Pumps using a piezoelectric element as an actuator are known in the art. Such pumps are also called diaphragm pumps. Since these pumps can discharge a very small amount of fluid, these pumps are used for fluid supply devices that are required to supply fluid with reduced frequency.
- JP 2004-108388 A Japanese Patent Application Publication No. 2004-108388 A
- JP 2012-102803 A disclose a fluid supply device using such a pump, specifically an oil supply device (oil supply unit) integral with a rolling bearing.
- fluid may not be discharged from the pump.
- the fluid supply device is an oil supply unit mounted integrally with a rolling bearing
- an abnormality may occur in the pump due to vibration etc., which may result in poor lubrication of the rolling bearing.
- an abnormal discharge detection device detects an abnormal fluid discharge operation in a fluid supply device, the fluid supply device including a drive unit that outputs a pulsed drive voltage, a piezoelectric element that is repeatedly deformed when the pulsed drive voltage is applied, and a storage unit that stores therein fluid to be supplied, and the fluid supply device discharging the fluid from the storage unit as volume of the storage unit decreases with the deformation of the piezoelectric element.
- the abnormal discharge detection device includes: a measurement unit that measures a terminal voltage of the piezoelectric element; and a determination unit that determines if the discharge operation is being performed normally or not based on whether or not the terminal voltage measured with the measurement unit has changed with time during application of a pulse of the drive voltage.
- FIG. 1 is a sectional view of a bearing device according to an embodiment, taken along a plane including a central axis of a shaft;
- FIG. 2 is a sectional view of the bearing device taken along line A-A in FIG. 1 ;
- FIG. 3 is a schematic view illustrating the configuration of a pump included in the bearing device
- FIG. 4 is a block diagram showing the configuration of an abnormal discharge detection device
- FIG. 5 is a waveform chart schematically showing a waveform of a terminal voltage during application of a pulse of drive voltage in the case where a piezoelectric element cannot be driven;
- FIG. 6 is a waveform chart schematically showing a waveform of the terminal voltage during application of a pulse of drive voltage in the case where the piezoelectric element is operating normally;
- FIG. 7 is a waveform chart showing the relationship between the terminal voltage and threshold voltages that are used for detecting an abnormality, in the case where a discharge operation is being performed normally;
- FIG. 8 is a waveform chart showing the relationship between the terminal voltage and the threshold voltages that are used for detecting an abnormality, in the case where a discharge operation is being performed abnormally;
- FIG. 9 is a flowchart illustrating a detection operation of an abnormal discharge detection device.
- FIG. 1 is a sectional view of a bearing device 100 equipped with an abnormal discharge detection device according to the present embodiment, taken along a plane including a central axis of a shaft.
- FIG. 2 is a sectional view of the bearing device 100 taken along line A-A in FIG. 1 .
- the bearing device 100 includes a power supply unit 10 , a bearing body 20 , an oil supply unit 40 that is an example of a fluid supply device, a drive unit 70 , and a control unit 80 .
- the bearing device 100 is accommodated in a bearing housing 8 in order to rotatably support, e.g., a spindle (shaft 7 ) of a machine tool.
- the bearing body 20 has an inner ring 21 , an outer ring 22 , a plurality of rolling elements (balls) 23 , and an annular cage 24 .
- the cage 24 holds the plurality of rolling elements 23 .
- the inner ring 21 is a cylindrical member that is fitted on the shaft 7 .
- the inner ring 21 has a raceway groove (hereinafter referred to as the inner ring raceway groove 25 ) in its outer periphery.
- the outer ring 22 is a cylindrical member that is fixed to an inner peripheral surface of the bearing housing 8 .
- the outer ring 22 has a raceway groove (hereinafter referred to as the outer ring raceway groove 26 ) in its inner periphery.
- the inner ring 21 and the outer ring 22 are concentrically disposed with an annular space 28 therebetween.
- the inner ring 21 rotates with the shaft 7 relative to the outer ring 22 .
- the plurality of rolling elements 23 are arranged in the annular space 28 between the inner ring 21 and the outer ring 22 and roll in the inner ring raceway groove 25 and the outer ring raceway groove 26 .
- the cage 24 is disposed in the annular space 28 .
- the cage 24 is an annular member.
- the cage 24 has a plurality of pockets 27 formed at regular intervals in the circumferential direction in order to hold the plurality of rolling elements 23 .
- the cage 24 has a plurality of annular portions 31 , 32 and a plurality of cage bars 33 .
- the pair of annular portions 31 , 32 are located on both sides in the axial direction of the rolling elements 23 .
- the cage bars 33 connect the annular portions 31 , 32 to each other.
- the plurality of cage bars 33 are formed at intervals in the circumferential direction.
- the pockets 27 are regions each surrounded by the annular portions 31 , 32 and two of the cage bars 33 which are adjacent to each other in the circumferential direction.
- a single rolling element 23 is accommodated in each pocket 27 , so that the cage 24 can hold the plurality of rolling elements 23 side by side in the circumferential direction.
- the oil supply unit 40 serving as a fluid supply device is disposed next to the annular space 28 of the bearing body 20 . Specifically, the oil supply unit 40 is disposed on one side in the axial direction of the annular space 28 of the bearing body 20 .
- the oil supply unit 40 can supply lubricant (oil) to the annular space 28 .
- Lubricant (oil) is one example of fluid.
- the oil supply unit 40 has a case 41 and a nozzle 42 . The nozzle 42 extends in the axial direction from the case 41 .
- a tank 62 and a pump 61 are disposed in the space inside the case 41 of the oil supply unit 40 .
- the tank 62 stores lubricant therein.
- the pump 61 can store lubricant therein.
- the pump 61 has a pressure chamber 63 , a diaphragm (vibrating plate) 64 ( FIG. 3 ), and a piezoelectric body 65 .
- the pump 61 supplies lubricant stored in the pressure chamber 63 .
- the diaphragm 64 is disposed so as to face the pressure chamber 63 .
- the piezoelectric body 65 is disposed on the back side of the pressure chamber 63 so as to be in contact with the diaphragm 64 .
- the piezoelectric body 65 is deformed when a voltage is applied.
- the diaphragm 64 disposed in contact with the piezoelectric body 65 is deformed with the deformation of the piezoelectric body 65 .
- the volume of the pressure chamber 63 of the pump 61 decreases with the deformation of the diaphragm 64 . That is, the diaphragm 64 transmits the deformation of the piezoelectric body 65 to the pressure chamber 63 .
- the power supply unit 10 , the drive unit 70 , and the control unit 80 are disposed in the space in the case 41 .
- the drive unit 70 drives the pump 61 mounted in the oil supply unit 40 .
- the control unit 80 is connected to the drive unit 70 and controls driving of the pump 61 by the drive unit 70 .
- the oil supply unit 40 thus performs an oil supply operation as controlled by the control unit 80 .
- the power supply unit 10 includes a battery, not shown, and supplies electric power to the control unit 80 .
- FIG. 3 is a schematic view illustrating the configuration of the pump 61 .
- the pump 61 is a diaphragm pump. Specifically, the pressure chamber 63 of the pump 61 has a suction port 63 a and a discharge port 63 b . The suction port 63 a extends to the tank 62 , and the discharge port 63 b communicates with the nozzle 42 .
- the pump 61 includes the diaphragm 64 , the piezoelectric body 65 , and a pair of electrodes 66 .
- the diaphragm 64 is disposed so as to face the pressure chamber 63 .
- the piezoelectric body 65 is disposed on the back side of the pressure chamber 63 so as to be in contact with the diaphragm 64 .
- the pair of electrodes 66 supply a voltage to the piezoelectric body 65 .
- the piezoelectric body 65 and the electrodes 66 form a piezoelectric element 69 .
- the drive unit 70 is connected to a terminal 68 of the piezoelectric element 69 by a power line 67 .
- the drive unit 70 outputs a constant pulsed drive voltage to the terminal 68 via the power line 67 .
- the terminal 68 is connected to the electrodes 66 .
- the piezoelectric body 65 is, e.g., a piezo element, and is deformed when a drive voltage is applied to the electrodes 66 .
- the piezoelectric body 65 When the drive unit 70 applies a drive voltage to the electrodes 66 , the piezoelectric body 65 is deformed (extended) to press the diaphragm 64 toward the pressure chamber 63 .
- the diaphragm 64 thus presses the pressure chamber 63 , whereby the volume of the pressure chamber 63 decreases accordingly.
- a small amount of lubricant is thus discharged from the pressure chamber 63 into the annular space 28 through the nozzle 42 . This operation is also referred to as a discharge operation.
- the piezoelectric body 65 that has been extended contracts and returns to its original position and thus stops pressing the diaphragm 64 . Since the piezoelectric body 65 stops pressing the diaphragm 64 , the volume of the pressure chamber 63 returns to its original volume, so that lubricant is introduced from the tank 62 into the pressure chamber 63 . That is, the pump 61 sucks lubricant from the tank 62 . This operation is also referred to as a suction operation.
- the pump 61 Since the drive unit 70 applies a constant pulsed drive voltage to the piezoelectric element 69 , the pump 61 alternately repeats suction and discharging operations. An operation of supplying lubricant from the oil supply unit 40 to the bearing body 20 (oil supply operation) is thus repeated.
- the control unit 80 also functions as an abnormal discharge detection device that detects an abnormal discharge operation in the oil supply unit 40 .
- FIG. 4 is a block diagram showing the configuration of the abnormal discharge detection device.
- the abnormal discharge detection device includes a measurement unit 13 in addition to the control unit 80 .
- the measurement unit 13 is connected to the power line 67 connecting the drive unit 70 and the electrodes 66 , and measures a voltage (terminal voltage) between the pair of electrodes 66 .
- the measurement unit 13 includes a converter, not shown, etc.
- the measurement unit 13 steps down the measured voltage (terminal voltage) to a voltage suitable for the control unit 80 and applies this voltage to the control unit 80 .
- the control unit 80 includes a microcomputer etc.
- the control unit 80 functions as a determination unit that determines if a discharge operation is being performed normally or not based on whether or not the measured terminal voltage has changed with time during application of a drive voltage.
- FIG. 5 is a waveform chart schematically showing a waveform of the terminal voltage during application T of a pulse of drive voltage, namely an output waveform of the drive unit 70 , in the case where the piezoelectric element 69 cannot be driven due to failure etc. of the piezoelectric element 69 .
- FIG. 6 is a waveform chart schematically showing a waveform of the terminal voltage during application T of a pulse of drive voltage in the case where the piezoelectric element 69 is operating normally. Referring to FIGS.
- the drive unit 70 outputs a voltage at certain intervals to apply a pulsed voltage E to the piezoelectric body 65 .
- the terminal voltage of the piezoelectric body 65 increases from its initial voltage EO with time during application T of a pulse of drive voltage and returns to the initial voltage EO immediately after application T of the pulse of drive voltage.
- the control unit 80 that functions as the determination unit determines that a discharge operation is being performed normally. In this case, contact of the piezoelectric body 65 with the electrodes 66 and the mechanism of the piezoelectric element 69 are normal.
- the waveform of FIG. 6 is therefore a reference waveform for determining that a discharge operation is being performed normally.
- the control unit 80 determines that a discharge operation is not being performed normally (a discharge operation is being performed abnormally). In this case, the control unit 80 classifies such an abnormal discharge operation into two types based on the waveform of the terminal voltage during application of a pulse of drive voltage.
- the control unit 80 determines that the abnormal discharge operation is due to an abnormality in a circuit in the pump 61 or an abnormality in a connection portion.
- an abnormality in the circuit in the pump 61 or an abnormality in the connection portion is an abnormality due to defective contact between the electrode 66 and the piezoelectric body 65 , defective connection between the electrode 66 and the terminal 68 , defective connection between the terminal 68 and the drive unit 70 , mechanical failure of the piezoelectric element 69 , etc.
- the control unit 80 determines that the abnormal discharge operation is due to an abnormality other than an abnormality in the circuit in the pump 61 .
- an abnormality other than an abnormality in the circuit in the pump 61 is an abnormality due to a defect in a circuit that applies a voltage to the electrodes 66 , an insufficiently charged battery, not shown, an abnormality in the electrode 66 , etc. That is, an abnormality other than an abnormality in the circuit in the pump 61 is an abnormality in the control unit.
- an abnormality other than an abnormality in the circuit in the pump 61 is an abnormality in the control unit.
- the control unit 80 determines if the terminal voltage has increased with time during application of a pulse of drive voltage or not based on at least two terminal voltages measured at at least two measurement times during application of a pulse of drive voltage. For example, measurement times t 1 , t 2 are set in advance in the control unit 80 (t 1 ⁇ t 2 ). The measurement times t 1 , t 2 are the points that divide the period of application T of a pulse of drive voltage into three approximately equal periods. Preferably, a measurement time t 3 immediately after application T of a pulse of drive voltage is also set in the control unit 80 (t 2 ⁇ t 3 ). The control unit 80 determines if terminal voltages E 1 , E 2 measured at the measurement times t 1 , t 2 by the measurement unit 13 have changed (increased) with time during the period from the measurement time t 1 to the measurement time t 2 .
- FIGS. 7 and 8 are waveform charts illustrating an example of a method for detecting an abnormal discharge operation by the abnormal discharge detection device.
- the control unit 80 stores in advance threshold voltages TA, TB corresponding to the measurement times t 1 , t 2 , respectively.
- the threshold voltage TA is higher than the initial voltage E 0 and is lower than the terminal voltage at the measurement time t 1 in the reference waveform of FIG. 6 .
- the threshold voltage TB is higher than the threshold voltage TA and is lower than the terminal voltage at the measurement time t 2 in the reference waveform of FIG. 6 .
- the control unit 80 compares the terminal voltages E 1 , E 2 with the threshold voltages TA, TB to determine if the terminal voltages E 1 , E 2 have increased with time during the period from the measurement time t 1 to the measurement time t 2 .
- FIG. 7 shows the relationship between the terminal voltage and the threshold voltages TA, TB in the case where the terminal voltage changes with time as shown in FIG. 6 .
- the terminal voltage E 1 is higher than the threshold voltage TA and is lower than the threshold voltage TB.
- the terminal voltage E 2 is higher than the threshold voltage TB.
- a terminal voltage E 3 is equal to the initial voltage and is lower than the threshold voltage TA.
- the expressions (1), (2) are herein referred to as the first condition. E3 ⁇ TA ⁇ E1 (1) TB ⁇ E2 (2)
- FIG. 8 shows the relationship between the terminal voltage and the threshold voltages TA, TB in the case where the terminal voltage does not change with time but has a rectangular waveform as shown in FIG. 5 .
- the terminal voltage E 1 and the terminal voltage E 2 are approximately the same and are higher than the threshold voltage TB.
- the terminal voltage E 3 is lower than the threshold voltage TA.
- the terminal voltages E 1 to E 3 satisfy the following expressions (3) to (6).
- the expressions (3) to (6) are herein referred to as the second condition.
- the first and second conditions are an example of conditions that are used to detect an abnormal discharge operation. That is, the first and second conditions are an example of a method for determining if the terminal voltage has changed with time during application of a pulse of drive voltage.
- the control unit 80 uses threshold voltages stored in advance therein. Whether the terminal voltage has changed with time during application of a pulse of drive voltage can thus be determined by a simple process.
- the control unit 80 may not use the terminal voltage E 3 , namely the terminal voltage immediately after application of a pulse of drive voltage, in this method. This makes the determination process simpler.
- FIG. 9 is a flowchart showing an example of a detection operation of the abnormal discharge detection device.
- the control unit 80 receives from the measurement unit 13 a voltage signal indicating a measured terminal voltage (step S 101 ).
- the control unit 80 reads terminal voltages E 1 , E 2 , E 3 from the voltage signal and compares the terminal voltages E 1 , E 2 , E 3 with prestored threshold voltages TA, TB. If the terminal voltages E 1 to E 3 satisfy the above expressions (1), (2), namely if the terminal voltages E 1 to E 3 satisfy the first condition (Yes in step S 103 ), the control unit 80 determines that a discharge operation is being performed normally (step S 105 ).
- the control unit 80 determines that there is an abnormality in the circuit in the pump 61 or the connection portion (step S 109 ).
- the control unit 80 determines that there is an abnormality in the control unit 80 (abnormality in a circuit in the drive unit 70 etc.) (step S 111 ).
- the abnormal discharge detection device includes a transmission unit that outputs information.
- the transmission unit may be wireless communication or may be a light emitting diode (LED), a buzzer, etc.
- the control unit 80 is also connected to the transmission unit to control transmission of the transmission unit. If an abnormal discharge operation is detected in step S 109 or step S 111 , the control unit 80 preferably controls the transmission unit to send an error notification (step S 113 ).
- the error notification may be a notification that distinguishes between the determination result of step S 109 and the determination result of step S 111 .
- the abnormal discharge detection device that detects an abnormal discharge operation in the fluid supply device, namely the oil supply unit 40 , determines if a discharge operation is being performed normally or not based on whether or not the terminal voltage has changed with time during application of a pulse of drive voltage. This eliminates the need for a special device such as a sensor, whereby an abnormal discharge operation can be detected easily and accurately. This makes it possible to quickly deal with abnormal fluid supply.
- the abnormal discharge detection device measures the terminal voltage at at least two measurement times t 1 , t 2 during application of a pulse of drive voltage to determine if the terminal voltage has changed with time during application of a pulse of drive voltage or not based on at least two measured terminal voltages E 1 , E 2 . Whether a discharge operation is being performed normally or not can thus be easily determined.
- the abnormal discharge detection device stores in advance the threshold voltages TA, TB for each measurement time and compares the each of at least two terminal voltages E 1 , E 2 with a corresponding one of the threshold voltages TA, TB.
- the abnormal discharge detection device can thus easily and accurately determine if the terminal voltage has changed with time during application of a pulse of drive voltage. Accordingly, whether a discharge operation is being performed normally or not can be easily and accurately determined.
- the first and second conditions are an example of conditions that are used to detect an abnormal discharge operation. That is, the first and second conditions are an example of a method for determining if the terminal voltage has changed with time during application of a pulse of drive voltage.
- the control unit 80 uses threshold voltages stored in advance therein. Whether the terminal voltage has changed with time during application of a pulse of drive voltage can thus be determined by a simple process.
- the control unit 80 may not use the terminal voltage E 3 , namely the terminal voltage immediately after application of a pulse of drive voltage, in this method. This makes the determination process simpler.
- the control unit 80 may compare the terminal voltages E 1 , E 2 to determine if the terminal voltages E 1 , E 2 satisfy E 1 ⁇ E 2 . Whether the terminal voltage has changed with time during application of a pulse of drive voltage or not can thus be determined by a simple process. Accordingly, whether a discharge operation is being performed normally or not can be easily determined.
- the control unit 80 may store in advance a rate of change ⁇ in terminal voltage per unit time.
- the rate of change ⁇ corresponds to the rate of change (gradient) in terminal voltage which is shown in the reference waveform of FIG. 6 .
- the control unit 80 determines if the amount of increase (E 2 -E 1 ) from the terminal voltage E 1 to the terminal voltage E 2 is equal to the amount of increase ⁇ (t 2 -t 1 ) obtained from the period (t 2 -t 1 ) from the measurement time t 1 to the measurement time t 2 and the rate of change ⁇ .
- the oil supply unit 40 mounted on the bearing device 100 is shown as an example of the fluid supply device.
- the fluid supply device is not limited to the oil supply unit that supplies oil to a bearing.
- the fluid supply device may be any device that supplies fluid by using a piezoelectric body such as a piezo element, like an oil supply unit that supplies oil to a hydraulic motor, a gear, etc.
- an abnormality in a pump mounted on a fluid supply device can be accurately detected.
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- General Engineering & Computer Science (AREA)
- Reciprocating Pumps (AREA)
- Rolling Contact Bearings (AREA)
Abstract
Description
E3≤TA≤E1 (1)
TB≤E2 (2)
TB≤E1 (3)
TB≤E2 (4)
E3≤TA (5)
E1≈E2 (6)
Claims (7)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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JP2016137881A JP6772605B2 (en) | 2016-07-12 | 2016-07-12 | Discharge abnormality detection device and its detection method |
JP2016-137881 | 2016-07-12 |
Publications (2)
Publication Number | Publication Date |
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US20180017052A1 US20180017052A1 (en) | 2018-01-18 |
US10385844B2 true US10385844B2 (en) | 2019-08-20 |
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US15/641,574 Active 2038-01-05 US10385844B2 (en) | 2016-07-12 | 2017-07-05 | Abnormal discharge detection device and abnormal discharge detection method |
Country Status (4)
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US (1) | US10385844B2 (en) |
JP (1) | JP6772605B2 (en) |
CN (1) | CN107605953B (en) |
DE (1) | DE102017115219A1 (en) |
Cited By (1)
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US10557502B2 (en) * | 2017-10-16 | 2020-02-11 | Jktekt Corporation | Rolling bearing device and oil supply unit |
Families Citing this family (4)
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JP6750296B2 (en) * | 2016-05-11 | 2020-09-02 | 株式会社ジェイテクト | Rolling bearing device |
JP6772789B2 (en) * | 2016-11-29 | 2020-10-21 | 株式会社ジェイテクト | Rolling bearing equipment, lubrication unit, lubricating oil supply method, and program |
JP2018173127A (en) * | 2017-03-31 | 2018-11-08 | 株式会社ジェイテクト | Rolling bearing device and oil supply unit |
JP2019049318A (en) * | 2017-09-11 | 2019-03-28 | 日本電気株式会社 | Bearing with measurement function |
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JP2004108388A (en) | 2002-09-13 | 2004-04-08 | Koyo Seiko Co Ltd | Rolling bearing device |
US20060165328A1 (en) | 2002-09-13 | 2006-07-27 | Hiroshi Ueno | Bearing device |
JP2012102803A (en) | 2010-11-10 | 2012-05-31 | Ntn Corp | Rolling bearing unit |
US20130052044A1 (en) * | 2011-08-30 | 2013-02-28 | Seiko Epson Corporation | Fluid feeding pump, medical apparatus, and air bubble detection method for fluid feeding pump |
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KR910012538A (en) * | 1989-12-27 | 1991-08-08 | 야마무라 가쯔미 | Micro pump and its manufacturing method |
JP5000453B2 (en) * | 2007-10-19 | 2012-08-15 | アルプス電気株式会社 | Piezoelectric pump with built-in driver |
EP2469089A1 (en) * | 2010-12-23 | 2012-06-27 | Debiotech S.A. | Electronic control method and system for a piezo-electric pump |
JP6051978B2 (en) * | 2013-03-14 | 2016-12-27 | セイコーエプソン株式会社 | Printing apparatus and nozzle inspection method |
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- 2017-07-07 DE DE102017115219.9A patent/DE102017115219A1/en active Pending
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US10557502B2 (en) * | 2017-10-16 | 2020-02-11 | Jktekt Corporation | Rolling bearing device and oil supply unit |
Also Published As
Publication number | Publication date |
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CN107605953B (en) | 2021-06-04 |
DE102017115219A1 (en) | 2018-01-18 |
US20180017052A1 (en) | 2018-01-18 |
JP6772605B2 (en) | 2020-10-21 |
JP2018009620A (en) | 2018-01-18 |
CN107605953A (en) | 2018-01-19 |
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