JP2005189058A - Impact sensor unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an impact sensor unit for early detection of the anomaly of a machine part by inspecting damage-causing impact received in assembly processes, transport process, etc. for the machine part, before the machine part is built into a mechanical device. <P>SOLUTION: This impact sensor unit 10 comprises an impact sensor 11, a detection/amplifying circuit 12, an arithmetic processing part 13, a storage part 14, and an output part 15, with these being integrally housed in a case 17. An impact acting on the machine part is detected by the sensor unit 10 mounted the machine part, such as a tapered roller bearing 1. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an impact sensor unit. More specifically, the present invention relates to an assembly process and a transport process of machine parts including rotating machines, sliding members, precision parts, optical parts, etc., and a railway vehicle and a machine incorporating these machine parts. The present invention relates to an impact sensor unit capable of performing diagnosis during operation of a mechanical device such as a machine or a windmill.

  Conventionally, in a bearing device that rotatably supports an axle of a railway vehicle and the like, periodic disassembly visual inspection has been performed in order to prevent the occurrence of inconvenience due to wear or breakage of a bearing component that is a sliding member. .

  In the disassembled visual inspection, after a certain period of use of the vehicle, the bearings are removed from the vehicle and disassembled, and a trained professional inspector confirms the degree of wear and the presence or absence of scratches of each component disassembled visually. If abnormalities such as unevenness and wear that are not found in the new parts are detected by this confirmation, the parts are replaced with new ones and reassembled.

  Also, in machine devices such as machine tools, motors, and automobile axle bearing units with built-in bearings, various sensors are attached to the bearings, and vibrations, temperatures, rotational speeds, etc. during operation are detected to detect abnormal bearings. What detects the presence or absence of this is known (for example, refer to Patent Document 1 and Patent Document 2).

The piezoelectric film conversion device for a bearing disclosed in Patent Document 1 is configured to attach a piezoelectric film converter for detecting a pressure wave generated in a bearing during operation to the bearing, and to monitor whether the bearing is damaged during operation. Has been. In the sensor-equipped bearing device disclosed in Patent Document 2, various sensors such as a vibration sensor, a rotation sensor, and a temperature sensor are incorporated in a single sensor holder and attached to the bearing device. It is configured to detect the operating state and to carry out preventive maintenance of the bearing.
JP-A-8-110285 (FIG. 1) JP 2003-65835 A (FIG. 1)

  However, in the conventional disassembled visual inspection, there is a possibility that individual differences may occur in the inspection results depending on the person inspecting, or defects may be overlooked. Further, in the visual disassembly inspection, there is a possibility that a dent is made on the bearing component parts during disassembly work for removing the bearing device from the vehicle or assembly work after the inspection. In particular, since a dent at the time of assembly work after inspection is detected as an abnormality during operation of the mechanical device, abnormality detection is delayed.

  Furthermore, since the built-in scratches of the bearing components that occur during the assembly of the bearing device are also detected by disassembling visual inspection, the bearing device is shipped to the customer with the built-in scratches, and costs such as transportation costs are wasted. There was a problem of becoming. This problem is remarkable in large-sized rolling bearings and the like.

  In addition, the sensors disclosed in Patent Document 1 and Patent Document 2 both detect an abnormality of the bearing device during operation of the mechanical device, and whichever of the bearings are damaged during the assembly process or the transport process, There was no data on whether the damage occurred in such a situation, the cause of the bearing damage could not be determined, and it was difficult to take measures against the bearing damage.

  For example, even if a small-diameter bearing for a small motor or the like has fretting wear or dents due to vibration / impact caused by a rough road during transportation, it was not detected until the bearing was inspected after being incorporated in the motor.

  In addition, since these sensors monitor and detect the abnormality of the bearing by calculating the output from the sensor element externally, it is difficult to detect the abnormality directly in the assembly process and the transportation process of the bearing. It was.

  The present invention has been made in view of the above-mentioned problems, and its purpose is to provide an impact that causes damage in the assembly process, the transport process, etc. of the machine part before the machine part is incorporated into the machine apparatus. An object of the present invention is to provide an impact sensor unit that can detect abnormalities of machine parts at an early stage.

The above object of the present invention can be achieved by the following constitution.
(1) An impact sensor unit comprising an impact sensor, a detection circuit, an arithmetic processing unit, and a storage unit.
(2) An impact sensor unit comprising a unit in which an impact sensor, a detection circuit, an arithmetic processing unit, a storage unit, and an output unit are integrated, and detects an impact of a mechanical part.
(3) The impact sensor unit according to (1) or (2), wherein the impact sensor is a sensor using either a piezoelectric element or a micromachine.
(4) The impact sensor unit according to (1) or (2), wherein the impact sensor is a piezoelectric sensor using either a ceramic piezoelectric element or a polymer piezoelectric element.
(5) The impact sensor unit according to (1) or (2), wherein the impact sensor is a micro acceleration sensor that forms a micromachine spring on a silicon wafer and detects acceleration from a change in capacitance of the spring. .
(6) The impact sensor includes both a piezoelectric sensor using either a ceramic piezoelectric element or a polymer piezoelectric element, and a micro acceleration sensor that forms a micromachine spring on a silicon wafer and detects acceleration based on a change in capacitance thereof. The impact sensor unit according to (1) or (2), wherein
(7) The impact sensor unit according to any one of (1) to (6), which is detachable from a mechanical part.
(8) A mechanical apparatus comprising the impact sensor unit according to any one of (1) to (7) attached to the mechanical part.
(9) The machine device according to (8), wherein the machine part performs at least one of assembly, adjustment, and packaging.
(10) A rolling bearing to which the impact sensor unit according to any one of (1) to (7) is applied.
(11) A motor to which the impact sensor unit according to any one of (1) to (7) is applied.
(12) A hub unit, wherein the impact sensor unit according to any one of (1) to (7) is applied to an automobile axle bearing unit.

  According to the impact sensor unit of the present invention, since the impact sensor, the detection circuit, the arithmetic processing unit, and the storage unit are integrated, the impact sensor unit can be configured compactly. Further, this makes it easy to mount the impact sensor unit on the machine part, and it is possible to detect an impact applied to the machine part during the assembly process, transport process, operation, etc. of the machine part.

  In addition, according to the impact sensor unit of the present invention, since the impact sensor, the detection circuit, the arithmetic processing unit, the storage unit, and the output unit are configured as a unit to detect the impact of the machine component, By mounting the impact sensor unit at any position, it is possible to detect impacts acting on the machine parts during the assembly process, transport process, operation, etc. of the machine parts.

  Various information such as the magnitude of impact acting on machine parts, the number of impacts exceeding a preset threshold, the time when the impact was applied, etc. are stored in the storage unit and output to the display unit and output unit. By doing so, it becomes possible to determine the cause of damage and to take measures against damage caused by impact. Also, this makes it possible to provide highly reliable machine parts and machines.

  According to the impact sensor unit of the present invention, since the impact sensor is a sensor using either a piezoelectric element or a micromachine, it can be detected according to impact acceleration in a low frequency band that causes damage to mechanical parts.

  According to the impact sensor unit of the present invention, since the impact sensor is a piezoelectric sensor using either a ceramic piezoelectric element or a polymer piezoelectric element, detection is performed according to impact acceleration in a low frequency band that causes damage to mechanical parts. can do. In addition, since the piezoelectric polymer element can be detected in a wide band from a low frequency band of 1 Hz or less to an ultrasonic band exceeding 1 MHz, impact acceleration, solid contact, plastic deformation, It is possible to detect an elastic wave (AE wave, ultrasonic wave) signal generated from the progress of a flaw in a mechanical component due to brittle fracture, crack propagation, or the like.

  According to the impact sensor unit of the present invention, since the impact sensor is a micro acceleration sensor that forms a micromachine spring on a silicon wafer and detects acceleration from the change in its capacitance, the impact sensor unit can be used as a mechanical component by an ultra-compact impact sensor unit. The impact in a wide frequency band from the acting DC to several kHz can be detected with high accuracy.

  According to the impact sensor unit of the present invention, the impact sensor includes a piezoelectric sensor using either a ceramic piezoelectric element or a polymer piezoelectric element, and a micromachine spring formed on a silicon wafer, and a micro sensor that detects acceleration from the capacitance change. Since both the acceleration sensors are included, it is possible to detect both impact acceleration in a relatively low frequency band up to several kHz and acceleration in a high frequency band including ultrasonic waves. As a result, it is possible to detect the possibility of scratches on machine parts in the assembly process, the transport process, and the like, and the abnormality of the bearing due to the damage. This also makes it possible to take measures against damage and provide a highly reliable impact sensor unit.

  According to the impact sensor unit of the present invention, the impact sensor unit can be attached to and detached from the machine part. For example, in the assembly process of the bearing device, the impact sensor unit is attached to the component parts such as the outer ring before the assembly. The apparatus can be assembled and adjusted, and the impact sensor unit can be removed and reused after assembly. As a result, high-quality machine parts can be manufactured at low cost.

  In addition, according to the mechanical device of the present invention, since the impact sensor unit is attached to the machine part, the magnitude of the impact load applied to the machine part, the number of times of application, the time when the impact was received, and the like are easily detected. This makes it possible to know the possibility of damage to the mechanical parts before the operation of the mechanical device, and to provide a highly reliable mechanical device.

  Further, according to the mechanical device of the present invention, since at least one of assembly, adjustment, and packaging is performed, it is possible to detect the impact received by the machine parts during assembly, adjustment, and packaging. From the data, it is possible to take a measure against the possibility that the machine part has been damaged or not. In addition, this makes it possible to provide a highly reliable mechanical device.

  Further, according to the present invention, since the impact sensor unit is applied to the rolling bearing, the impact acting on the rolling bearing in the assembly process, the transport process, etc. is detected, and the cause of the damage given to the raceway surface and the rolling element is detected. It can be known before the rolling bearing is incorporated into the mechanical device. Therefore, a highly reliable mechanical device can be provided at low cost.

  Further, according to the present invention, since the impact sensor unit is applied to the motor, it is possible to detect the impact that causes the motor abnormality, determine the cause of the failure, and prevent the motor abnormality.

  Further, according to the present invention, since the impact sensor unit is applied to an automobile axle bearing unit, it is possible to detect an impact that causes an abnormality of the automobile axle bearing unit and provide a highly reliable hub unit. it can.

  Since the impact sensor unit of the present invention integrates the impact sensor, the detection circuit, the arithmetic processing unit, and the storage unit, the impact sensor unit can be configured compactly. Further, the impact sensor unit can be easily attached to the machine part, and the impact applied to the machine part during the assembly process, the transport process, the operation, etc. of the machine part can be detected.

  Hereinafter, an impact sensor unit according to each embodiment of the present invention will be described in detail with reference to the drawings.

(First embodiment)
First, an impact sensor unit according to a first embodiment of the present invention will be described with reference to FIGS. 1 and 2.
FIG. 1 is an exploded side view showing a rolling bearing (conical roller bearing) which is a mechanical component according to the first embodiment of the present invention. 2 is an impact sensor unit in FIG. 1, (a) is a configuration diagram, and (b) is a side view.

  As shown in FIG. 1, the tapered roller bearing 1 includes an outer ring 2, an inner ring 3, a tapered roller 4 that is a rolling element, and a cage 5 as components. A conical raceway surface 2 a is formed on the inner peripheral surface of the outer ring 2, and a conical raceway surface 3 a is formed on the outer peripheral surface of the inner ring 3. Between the raceway surface 2 a of the outer ring 2 and the raceway surface 3 a of the inner ring 3, a plurality of tapered rollers 4 that are rotatably held by a cage 5 are rotatably arranged. The impact sensor unit 10 is detachably fixed to the outer peripheral surface 2b of the outer ring 2.

  As shown in FIG. 2, the impact sensor unit 10 is for detecting an impact load acting on the tapered roller bearing 1, and includes an impact sensor 11, a detection amplification circuit 12, an arithmetic processing unit 13, a storage unit 14, The output unit 15 is disposed on the circuit board 16 so as to be electrically connected.

The circuit board 16 is fixed in the case 17 by a plurality of screws 18 which are board fixing members. The case 17 is made of aluminum alloy, magnesium alloy, iron, or the like, and the mounting surface 17a of the case 17 has a radius of curvature of the outer peripheral surface 2b of the outer ring 2 so that the case 17 is fixed in close contact with the outer peripheral surface 2b of the outer ring 2. (See FIG. 2B). The screws 18 are arranged at the four corners of the circuit board 16 and also in the vicinity of the position where the impact sensor 11 is arranged.
Thereby, the impact sensor unit 10 including the impact sensor 11, the detection circuit 12, the arithmetic processing unit 13, the storage unit 14, and the output unit 15 is configured as an integral unit.

  The impact sensor 11 is made of a bimorph ceramic piezoelectric element and is surface-mounted on a circuit board 16. The impact sensor 11 detects the applied impact as an acceleration and outputs an electrical signal proportional to the acceleration. The impact sensor 11 may be a voltage-sensitive type that outputs an electric signal as a voltage with respect to the value of the gravitational acceleration G, or may be a charge-sensitive type that outputs as an electric charge. The acceleration detected by the impact sensor 11 is amplified by the detection amplification circuit 12 and converted into an appropriate voltage signal. When the charge sensitive impact sensor 11 is used, it is converted to a voltage by a charge amplifier in which a capacitor is inserted in the feedback section of the first stage operational amplifier. Although the input of the detection amplifier circuit 12 requires high impedance, it is usually set to a value of about 1 MΩ to 1 GΩ.

  The arithmetic processing unit 13 is, for example, a microcomputer (hereinafter referred to as a microcomputer), determines whether or not the impact acceleration detected by the impact sensor 11 exceeds a preset threshold value, and outputs a logical output when the threshold value is exceeded. The fact that an abnormal impact has been applied is written in the storage unit 14. Here, the threshold value is set to the magnitude of impact that may damage the tapered roller bearing 1. The storage unit 14 stores the magnitude of impact acceleration that has acted on the impact sensor unit 10, the number of times that impact acceleration greater than the threshold value has been actuated, the time at which impact acceleration has acted, and the like.

  The output unit 15 includes a liquid crystal display panel as a display unit, and displays whether or not there has been a history of abnormal impact. The output unit 15 may be any device that informs the outside of the detection result of the impact acceleration by the impact sensor 11, such as a sound generating element such as a buzzer, a light emitting element such as an LED, a wireless antenna that can communicate with the host computer, and the like. It may be configured by both a display unit and other outputs. In the case of wireless communication, the impact history is read from a host computer provided outside.

Next, the operation of the impact sensor unit of the first embodiment will be described.
As shown in FIGS. 1 and 2, for example, when detecting an impact in a manufacturing process (assembly / adjustment process) of a large tapered roller bearing 1, first, an outer ring 2, an inner ring 3, a tapered roller 4 and a cage. Each component such as 5 is completed through processes such as turning, heat treatment, polishing, and inspection. Thereafter, the impact sensor unit 10 is closely attached and fixed to the outer peripheral surface 2 b of the completed outer ring 2, and then the inner ring 3, the tapered roller 4 and the cage 5 are assembled to the outer ring 2.

  In the manufacturing process of the tapered roller bearing 1, when an impact acts on the tapered roller bearing 1, the impact sensor 11 detects the impact as an acceleration, and amplifies it by the detection amplification circuit 12, and outputs an electrical signal. The arithmetic processing unit 13 processes the electric signal and compares it with a preset threshold value, and when the detected impact acceleration is larger than the threshold value, the magnitude of the impact acceleration applied to the outer ring 2 and the impact larger than the threshold value. The number of times the acceleration is applied, the time, etc. are output to the storage unit 14 and stored as an impact history.

  The output unit 15 displays the impact history stored in the storage unit 14 on the liquid crystal display panel, and determines whether or not an impact that causes damage to the tapered roller bearing 1 is applied in the manufacturing process. The output unit 15 may be configured by a wireless antenna, and the impact history may be read from an external host computer by wireless communication. Further, based on the impact history stored in the storage unit 14, the possibility and timing of damage to the tapered roller bearing 1 may be determined by a logic circuit or MPU software.

  As a result, the possibility and timing of damage to the tapered roller bearing 1 can be determined during assembly and adjustment of the tapered roller bearing 1 or in a manufacturing inspection process before being shipped from the factory. Therefore, it is possible to supply the tapered roller bearing 1 with stable quality and high reliability. Moreover, the impact sensor unit 10 is removed from the tapered roller bearing 1 after the manufacturing inspection process before shipment, and is repeatedly used.

  Therefore, according to the impact sensor unit 10 of the present embodiment, a unit in which the impact sensor 11, the detection circuit 12, the arithmetic processing unit 13, and the storage unit 14 are integrated is configured to detect a mechanical part impact. . Thereby, the impact sensor unit 10 can be made compact, the mounting of the impact sensor unit 10 to the tapered roller bearing 1 can be facilitated, and the impact in the assembly process of the tapered roller bearing 1 can be detected.

  Further, various information such as the magnitude of the impact acting on the machine part, the number of times the impact exceeding the preset threshold is applied, and the time when the impact is applied is stored in the storage unit 14, and these information are stored in the output unit 15. , The cause of damage can be determined, and measures against the damage can be taken to provide a highly reliable tapered roller bearing 1.

  Furthermore, according to the impact sensor unit 10 of the present embodiment, the impact sensor unit 10 can be attached to and detached from the tapered roller bearing 1. For example, in the assembly process of the tapered roller bearing 1, the configuration of the outer ring 2 and the like before assembly. The impact sensor unit 10 can be attached to a part, assembled, adjusted, etc., and then the impact sensor unit 10 can be removed for reuse. Further, when a battery is used as the power source, the impact sensor unit 10 is reused after performing battery check and charging. As a result, the high-quality tapered roller bearing 1 can be produced at a low cost.

Further, according to the impact sensor unit 10 of the present embodiment, the case 17 is made of an aluminum alloy, a magnesium alloy, iron, or the like, and the mounting surface 17a of the case 17 is defined by the curvature radius of the outer peripheral surface 2b of the outer ring 2. Since the case 17 is formed in a curved surface having substantially the same radius of curvature and fixed in close contact with the outer peripheral surface 2 b of the outer ring 2, vibration, impact acceleration, elastic waves, etc. of the tapered roller bearing 1 are applied to the impact sensor 11. Reliable transmission.
The fixed position of the impact sensor unit 10 may be the side surface of the outer ring 2 or the side surface of the inner ring 3 as indicated by a broken line in FIG. 1, and is fixed at an arbitrary position suitable for detection. When fixing to the side surface of the outer ring 2 or the inner ring 3, the mounting surface of the case 17 is preferably a flat surface.

  Furthermore, since the impact sensor 11 is disposed at a position very close to the screw 18 and the screw 18 is provided in the vicinity of the impact sensor 11, vibration, impact acceleration, and the like transmitted from the tapered roller bearing 1 to the case 17 are reduced. The elastic wave is reliably transmitted to the impact sensor 11 without being affected by the natural vibration of the circuit board 16. The circuit board 16 may be fixed by filling the case 17 with an epoxy resin or the like.

In the present embodiment, the impact sensor unit 10 is detachably fixed to the tapered roller bearing 1. However, after the tapered roller bearing 1 is incorporated into a mechanical device, the impact sensor unit 10 monitors vibrations during operation. In that case, the outer ring 2 may be permanently incorporated in the outer peripheral surface 2b.
For this reason, the case 17 and the tapered roller bearing 1 may be fixed using an adhesive, a magnet, a double-sided adhesive tape, a rubber band, a spring, a screw, or the like according to the usage method of the impact sensor unit 10. You may make it fix a screw to the tap cut off for the injection hole etc. The fixing method is not particularly limited as long as it can reliably transmit the vibration, impact acceleration, and elastic wave of the tapered roller bearing 1 to the impact sensor 11.

(Second Embodiment)
Next, an impact sensor unit according to a second embodiment of the present invention will be described with reference to FIG. FIG. 3 is a schematic view for detecting an impact acting on a product during transportation when the impact sensor unit is mounted on a product packaging box.

  As shown in FIG. 3, machine parts such as rolling bearings manufactured at the manufacturing factory 20 are stored in a packing box 21 and conveyed to a plant factory 24 or the like as a customer by a transportation means 23 such as a truck. At this time, the impact sensor unit 22 is attached to the packaging box 21. Since the configuration and mounting of the impact sensor unit 22 are the same as those of the impact sensor unit 10 of the first embodiment, the description thereof is omitted.

  When delivering or delivering to a customer, the impact history stored in the impact sensor unit 22 is confirmed, and the damage received by the mechanical component during packaging or during transportation from the magnitude and frequency of the impact received by the mechanical component (the mechanical component is In the case of a rolling bearing, it is determined whether or not fretting wear or the like is present, and whether or not delivery is possible and whether or not it is incorporated into a mechanical device in the plant factory 24 are determined. Thereby, it is possible to provide the customer with mechanical parts having stable quality. Such an inspection system can be more reliably assured by the cooperation of the customer, the transporter, and the manufacturer.

  According to the present embodiment, it is possible to detect an impact received by a machine part during packaging or transportation, and it is possible to implement a countermeasure against the possibility that the machine part has been damaged from these data. Become. In particular, since a shock that has acted on a mechanical part during packaging or transportation can be known before being incorporated into the mechanical device, a highly reliable mechanical device can be provided.

  In the present embodiment, the impact sensor unit 22 is attached to the packing box 21 to detect the impact of the mechanical parts. However, the impact sensor unit 22 is attached to a mechanical part such as a rolling bearing as in the first embodiment. You may make it perform the impact detection of the machine parts in packing or in transportation. Thereby, it is possible to detect the impact of the machine part from assembly / adjustment process of the machine part to packing / transportation process, as well as assembly when the machine part is incorporated into the machine apparatus and operation of the machine apparatus.

(Third embodiment)
Next, an impact sensor unit according to a third embodiment of the present invention will be described with reference to FIGS. 4A and 4B show an impact sensor unit according to a third embodiment of the present invention. FIG. 4A is a configuration diagram, and FIG. 4B is a longitudinal sectional side view. FIG. 5 is a longitudinal sectional side view of an impact sensor unit which is a modification of the third embodiment of the present invention. FIG. 6 is a configuration diagram of an impact sensor unit which is another modification of the third embodiment of the present invention.

As shown in FIG. 4, in the impact sensor unit 30 of the third embodiment, a piezo film 31 is affixed to the inner surface of an aluminum alloy, magnesium alloy, or iron case 17 as an impact sensor. In the case 17, a circuit board 16 is fixed, in which the detection amplifier circuit 12, the storage / arithmetic processing unit 32, and the output unit 15 are electrically connected. The storage / arithmetic processing unit 32 is an integration of the arithmetic processing unit 13 and the storage unit 14 in the first embodiment, and has an equivalent function. Further, the piezo film 31 and the detection amplifier circuit 12 are electrically connected. Therefore, the impact sensor composed of the piezo film 31, the detection amplification circuit 12, the storage / arithmetic processing unit 32, and the output unit 15 are configured as an integrated unit.
The piezo film 31 may be affixed to the outer surface of the case 17 or may be affixed to the circuit board 16 as shown in FIG. 5 to further reduce the size of the impact sensor unit 30.

  The piezo film 31 is made of a polymer piezoelectric element such as polyvinylidene fluoride (PVDF) having a piezoelectric effect, and can capture a very wide frequency band from a low frequency signal of 1 Hz or less to an ultrasonic signal significantly exceeding 1 MHz. . Further, since the piezo film 31 is thin, it does not have a specific resonance point (natural frequency), so that the transmission / reception band can be freely set by the detection amplifier circuit 12.

  In the impact sensor unit 30 of the present embodiment, the reception band is set to about several kHz or less, and the storage / arithmetic processing unit 32 sets the magnitude of impact that may damage mechanical parts as a threshold value in advance. Thus, by comparing the detected impact acceleration with a threshold value, it is possible to determine whether or not an abnormal impact has occurred in the mechanical component. Therefore, similarly to the first embodiment, it is possible to detect the impact of the mechanical component with a compact configuration in which the impact sensor unit 30 is integrated.

  Further, for example, if the reception band is set to 100 kHz to 1 MHz, the AE (Acoustic Emission) generated from the progress of scratches on the rolling bearing, which is a mechanical component, is detected, the degree of wear of the rolling bearing, the degree of damage, It is possible to estimate damaged components and the like. Accordingly, it is possible to simultaneously detect the possibility of occurrence of scratches due to abnormal impacts in the assembly process, the transport process, and the like, and abnormalities during operation caused by the scratches. Furthermore, measures against damage can be taken, and a highly reliable mechanical device can be provided.

  Here, as a modified example of the present embodiment, an impact sensor unit 40 shown in FIG. 6 includes an impact sensor 41 that detects acceleration (impact acceleration) in a low frequency band up to about several kHz, both of which are made of a piezo film. An AE sensor 42 that detects acceleration in a high frequency band up to the ultrasonic wave is provided in the case 17. Thereby, the impact sensor unit 40 detects an impact causing damage to the rolling bearing or the like by the impact sensor 41 and detects an ultrasonic wave (AE) generated in the process of damage to the rolling bearing or the like by the AE sensor 42. Therefore, the cause of damage and the result of damage can be detected at the same time, and a reliable diagnosis can be performed.

In particular, when rolling bearings are installed, if there is a scratch due to a material defect, the scratch will be exposed by AE caused by visual inspection or scratches. By setting the threshold value in advance, it is possible to detect an impact that causes damage. Therefore, by using the impact sensor unit 40, it is possible to perform destructive inspection at a lower cost than non-destructive inspection.
In addition, by using the impact sensor unit 40 for machine diagnosis during transportation and operation of the rolling bearing, it is possible to simultaneously capture the AE signal generated from the impact acceleration and the progress of the flaw.

(Fourth embodiment)
Next, an impact sensor unit according to a fourth embodiment of the present invention will be described with reference to FIG. FIG. 7 is a configuration diagram of an impact sensor unit according to the fourth embodiment of the present invention.
As shown in FIG. 7, the impact sensor unit 50 includes a micro acceleration sensor 51, which is an impact sensor, a one-chip microcomputer 52 having functions of an arithmetic processing unit and a storage unit on one circuit board 16, an output. The part 15 is arranged as a unit. The circuit board 16 is fixed in the case 17 and can be mounted together with the case 17 on a mechanical part such as a rolling bearing.

  The micro acceleration sensor 51 is a micromachine, a so-called MEMS (Micro Electro Mechanical Systems) acceleration sensor, which has a spring formed on a silicon wafer by a micromachining technique, and detects acceleration by capturing the movement of the spring as a capacitance change. The micro acceleration sensor 51 also includes an A / D converter and the like and can be directly connected to a microcomputer.

  The micro acceleration sensor 51 has an advantage that it can detect acceleration of a frequency from a DC component to several kHz, which cannot be detected by a piezoelectric sensor, and has an impact resistance of 1000 G or more. Further, since the micro acceleration sensor 51 is sensitive to directionality, by using a biaxial sensor, it is possible to detect the direction of impact force and gravity simultaneously with the magnitude of impact acceleration.

  The detection signal detected by the micro acceleration sensor 51 is signal-processed by the one-chip microcomputer 52, and the detected impact acceleration is compared with a threshold value as in the first embodiment, and the magnitude of the impact acceleration exceeds the threshold value. Various information such as the number of times and the time when the impact acceleration is applied is stored.

  According to the impact sensor unit 50 of the present embodiment, the same effects as those of the impact sensor unit 10 of the first embodiment can be obtained. In addition, the impact sensor forms a micromachine spring on a silicon wafer, and Since the micro acceleration sensor 51 that detects acceleration from a change in capacitance is used, a frequency band from a DC component to several kHz can be detected. As a result, a highly reliable diagnosis can be performed regarding the possibility of scratches on machine parts in the assembly process, transport process, and the like.

  The impact sensor unit 40 shown in FIG. 6 may be configured by replacing the impact sensor 41 made of a piezo film with a micro acceleration sensor 51. That is, if a combination of the micro acceleration sensor 51 capable of detecting a low frequency of about 5 kHz from DC and the piezoelectric sensor 42 using a ceramic piezoelectric sensor or a polymer piezoelectric sensor capable of detecting an ultrasonic wave is used, Simultaneous detection of impact acceleration that causes damage and elastic wave (AE wave, ultrasonic) signals generated in the course of damage, such as metal contact and crack growth, plastic deformation, brittle fracture, dropout of foreign particles, etc. Can perform more reliable diagnosis

Note that the present invention is not limited to the above-described embodiments and modifications, and modifications and improvements can be made as appropriate.
In the present embodiment, the mechanical component is described as a rolling bearing, but is not limited to this, and includes, for example, a sliding member such as a ball screw and a linear guide, a rotating machine, a precision component, an optical component, and the like.

  The mechanical device of the present invention is a mechanical device incorporating a mechanical part to which an impact sensor unit is fixed, and includes a motor, a hub unit incorporating a vehicle axle bearing unit that is a mechanical part, a railway vehicle, a machine tool, and a windmill. Etc.

It is a side view which decomposes | disassembles and shows the rolling bearing (conical roller bearing) which is a machine component of 1st Embodiment of this invention. It is an impact sensor unit in FIG. 1, (a) is a block diagram, (b) is a side view. It is an impact sensor unit which concerns on 2nd Embodiment of this invention, is a schematic diagram which shows the state which the impact sensor unit is mounted | worn with the packaging box of a product, and detects the impact which acts on a product during transport. It is the impact sensor unit which is 3rd Embodiment of this invention, (a) is a block diagram, (b) is a longitudinal cross-sectional side view. It is a block diagram of the impact sensor unit of the modification of 3rd Embodiment. It is a block diagram of the impact sensor unit of the other modification of 3rd Embodiment. It is a block diagram of the impact sensor unit which is 4th Embodiment of this invention.

Explanation of symbols

1 Tapered roller bearing (rolling bearing)
10, 22, 30, 40, 50 Impact sensor unit 11 Ceramic piezoelectric element (impact sensor)
12 Detection Circuit 13 Arithmetic Processing Unit 14 Storage Unit 15 Output Unit 31 Piezo Film (Shock Sensor, Polymer Piezoelectric Element)
51 Micro acceleration sensor (impact sensor)

Claims (12)

  An impact sensor unit comprising an impact sensor, a detection circuit, an arithmetic processing unit, and a storage unit.   An impact sensor unit comprising a unit in which an impact sensor, a detection circuit, an arithmetic processing unit, a storage unit, and an output unit are integrated to detect an impact of a mechanical component.   The impact sensor unit according to claim 1, wherein the impact sensor is a sensor using any one of a piezoelectric element and a micromachine.   The impact sensor unit according to claim 1, wherein the impact sensor is a piezoelectric sensor using either a ceramic piezoelectric element or a polymer piezoelectric element.   The impact sensor unit according to claim 1 or 2, wherein the impact sensor is a micro acceleration sensor that forms a micromachine spring on a silicon wafer and detects acceleration from a change in capacitance of the spring.   The impact sensor includes both a piezoelectric sensor using either a ceramic piezoelectric element or a polymer piezoelectric element, and a micro acceleration sensor that forms a micromachine spring on a silicon wafer and detects acceleration based on a change in its capacitance. The impact sensor unit according to claim 1 or 2.   The impact sensor unit according to any one of claims 1 to 6, wherein the impact sensor unit is removable from a mechanical part.   A mechanical device comprising the impact sensor unit according to any one of claims 1 to 7 attached to the mechanical component.   The machine device according to claim 8, wherein the machine part performs at least one of assembly, adjustment, and packaging.   A rolling bearing to which the impact sensor unit according to any one of claims 1 to 7 is applied.   A motor to which the impact sensor unit according to any one of claims 1 to 7 is applied.   A hub unit, wherein the impact sensor unit according to any one of claims 1 to 7 is applied to an automobile axle bearing unit.

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